Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Bulbo olfattivo
Cavità nasale
Lingua
Aroma ortonasale
Gusto Aroma retronasale
Profumi, sapori e colori: aspetti chimici e sensoriali
SAPORE = GUSTO + AROMA RETRONASLE
Possiamo dividere le tecniche applicabili allo studio del gusto e degli aromi in: CHIMICHE
cromatografia, spettrometria di massa
SENSORIALI panel di rinoanalisti/assaggiatori
COMBINATE GC-O, naso elettronico, bocca artificiale
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
Similar behavior is seen, except that the minimum apparent
size is slightly smaller and the EGCG/casein ratio at which
the minimum occurs is much higher, at approximately 10.
This matches the DLS results but not the SAXS and
viscometry results. It is striking that the two experiments in
which the solution was prefiltered give minima at a ratio of
10, while the other experiments give minima at a ratio of
approximately 0.25.
Discussion
This study is aimed at deriving a molecular description
of the interactions between proteins (particularly salivary
basic PRPs) and dietary polyphenols, which are thought to
be responsible for the astringent sensation of polyphenol-
rich foods and beverages such as red wine and tea. The
purification of single PRPs from saliva is laborious, so as a
substitute for PRPs, bovine !-casein was used. This is cheapand easily available and has a number of similarities with
PRPs: it shares a similar extended conformation, with
exposed prolines,25,26 it competes with gelatin to bind to
polyphenols,7 and it binds to wine polyphenols in a similar
way to the established model polyvinyl-polypyrrolidone,although there is a lower density of polyphenol binding
sites.45 Dephosphorylation removes the hydrophilic phos-
phates and, therefore, reduces the tendency of casein to bind
calcium and form micelles.46
Polyphenols are multidentate ligands able to bind simul-
taneously, via different phenolic groups, at more than one
point on the protein strand.1,47 It has previously been
suggested that polyphenol-protein precipitation occurs inthree stages.15 Here, we have confirmed and expanded the
three-stage model (Figure 8):
(1) The free proteins exist in a loose, randomly coiled
conformation. Simultaneous binding of the multidentate
polyphenols to several sites on the protein leads to coiling
of the protein around the polyphenols. This causes the
physical size to decrease and the structure of the protein to
become more compact and spherical. Chelated binding at
several sites increases the overall binding affinity: in support
of this statement, we note that the affinity of a full-length
PRP (70 residues) for polyphenols is much greater than that
of a 19-residue single PRP sequence.20
(2) As the polyphenol concentration rises, polyphenols
complexed onto the protein surface cross-link different
protein molecules and dimerization ensues, causing insolubil-
ity.15 This phenomenon is similar to the precipitation of
Figure 7. Hydrodynamic radius of EGCG/casein mixtures, deter-mined by NMR PGSE experiments. (A) Unfiltered solutions. The graphin the inset shows the integrated intensity of the casein NMR signalsrelative to the same concentration of free casein, which should beconstant as long as casein remains soluble. The dashed line indicatesthe ratio at which visible precipitation was first observed. (B) Filteredsolutions.
Figure 8. Proposed binding model: The original random coiled PRP binds to multidentate polyphenols on more than one site because eachproline and each aromatic ring represents a possible binding site. At a low polyphenol concentration, the protein binds in several places to thepolyphenol molecules leading to a contraction of the loose random coil and decrease in the molecular size of the protein. Upon addition of morepolyphenols, intermolecular cross-linking takes place and aggregates are formed that finally precipitate.
948 Biomacromolecules, Vol. 5, No. 3, 2004 Jobstl et al.
Molecular Model for Astringency Produced by Polyphenol/Protein Interactions
Elisabeth Jobstl,†,‡ John O’Connell,§ J. Patrick A. Fairclough,† and Mike P. Williamson*,‡
Department of Molecular Biology and Biotechnology and Department of Chemistry, University of Sheffield,Sheffield S10 2UH, United Kingdom, and Unilever Research, Colworth House, Sharnbrook,
Bedford MK44 1LQ, United Kingdom
Received December 8, 2003; Revised Manuscript Received February 6, 2004
Polyphenols are responsible for the astringency of many beverages and foods. This is thought to be caused
by the interaction of polyphenols with basic salivary proline-rich proteins (PRPs). It is widely assumed that
the molecular origin of astringency is the precipitation of PRPs following polyphenol binding and the
consequent change to the mucous layer in the mouth. Here, we use a variety of biophysical techniques on
a simple model system, the binding of !-casein to epigallocatechin gallate (EGCG). We show that at lowEGCG ratios, small soluble polydisperse particles are formed, which aggregate to form larger particles as
EGCG is added. There is an initial compaction of the protein as it binds to the polyphenol, but the particle
subsequently increases in size as EGCG is added because of the incorporation of EGCG and then to
aggregation and precipitation. These results are shown to be compatible with what is known of astringency
in foodstuffs.
Introduction
Polyphenols are widely distributed in the plant kingdom
and, therefore, commonly found in plant-based foods and
beverages.1 They are characterized by containing several
phenolic groups (often in the form of galloyl [3,4,5-
trihydroxybenzoyl] groups) and have been found to have a
variety of effects on animals including humans.2,3 Polyphe-
nols of intermediate size have the ability to bind to proteins
and precipitate them and, hence, are also known as tannins.1,2
They have been suggested to reduce the nutritional value of
some foodstuffs,4-7 but they are also important constituents
of many foods and beverages, such as red wine and tea,
because it is the astringency of the tannins in these beverages
that gives them many of their desirable qualities. It is widely
believed that salivary proteins may act as a primary defense
against harmful (mainly higher molecular weight) tannins
by forming insoluble complexes with them and preventing
their absorption from the intestinal canal and interaction with
other biological compounds.2,3,8 The interaction of polyphe-
nols with salivary proteins has long been thought to lead to
the sensation of astringency, which is generally recognized
as a feeling of puckeriness and dryness in the palate.2,5,6,9 It
is not confined to a particular region of the mouth but is a
diffuse surface phenomenon, characterized by a loss of
lubrication,10 which takes a time of the order of 15-20 s todevelop fully.11,12 It is, therefore, quite different from the
more well-known taste sensations.
A mucous layer composed of salivary proteins and
glycoproteins covers the exposed surface of the mouth to
maintain lubrication. The primary reaction leading to the
sensation of astringency is the precipitation of proteins and
mucins by polyphenolic compounds. The essential feature
is the cross-linking of polypeptides by surface-exposed
phenolic groups on the polyphenols, leading to aggregation
and precipitation and, therefore, the occurrence of the
astringent response.13-15 Saliva is produced by salivary glands
and contains a variety of proteins. The major protein
constituent of saliva is a group of proteins consisting of
multiple repeats of an unusual amino acid sequence contain-
ing a large amount of proline, commonly referred to as
proline-rich proteins (PRPs).16,17 Of the three groups of PRPs
(acidic, basic, and glycosylated), the main function of the
basic PRPs seems to be the complexation of polyphe-
nols.2,14,18
The molecular interaction of polyphenols with PRPs has
been studied using a peptide containing a typical repeat
sequence of a mouse PRP and the human basic PRP IB-
5.15,19,20 It was shown that the major requirement is for the
peptide to have an extended conformation and that the
principal binding sites on these peptides are prolines and the
preceding amide bonds together with the preceding amino
acid (see also ref 18). The pyrrolidine rings of the prolyl
groups act as potential binding sites and form “hydrophobic
sticky patches” that stack face to face with the galloyl rings
of the phenolic substrate. Other interactions including
hydrogen bonding interactions can further stabilize the
complex.21
There is, thus, a good deal known about the molecular
basis of polyphenol/protein interactions. However, the events
after binding are not as well understood, not least because
* To whom correspondence should be addressed. Fax+44 114 272 8697.E-mail [email protected].
† Department of Chemistry, University of Sheffield.‡ Department of Molecular Biology and Biotechnology, University of
Sheffield.§ Unilever Research.
942 Biomacromolecules 2004, 5, 942-949
10.1021/bm0345110 CCC: $27.50 © 2004 American Chemical SocietyPublished on Web 03/13/2004
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O
OH
OHOH
O
O
OH
OH
OH
O
O
OH
OH
OH
OO
OH
OH
OH
O
O
OH
OH
OH
O
O
OH
OH
OH
OH
O
!-1,2,3,4,6-pentagalloyl-O-D-glucose
gallic acid
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$),56)5,#"+#'#1+#1)7!!!
Copyright © 2002, 2010 by Ann E. Hagerman. All rights reserved. 2
Il colore del vino è dovuto alla presenza di composti non volatili, appartenenti alla classe delle antocianine.
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
O
OH
OH
OHOH
OH+
Cianidina: ROSSO pH < 3, VIOLA pH 7-8, BLU pH > 11
La tecnica analitica di elezione è la cromatografia liquida.
HPLC GC
composti volatili
composti volatili pesanti o polari derivatizzabili
composti non volatili
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
In generale:
Profumi, sapori e colori: aspetti chimici e sensoriali
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI CHIMICI - LA CROMATOGRAFIA
La cromatografia è il metodo attualmente più diffuso
ed efficace per operare la separazione delle sostanze
in miscela a scopo analitico e preparativo.
Particolarmente utile per la separazione dei composti
organici, la cromatografia fu introdotta nel 1901 dal
botanico italo-russo Mikhail Semyonovich Tsvet
(1872-1919), che la applicò alla separazione di
pigmenti vegetali quali le clorofille ed i carotenoidi.
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI CHIMICI - LA CROMATOGRAFIA
H. Wagner, S. Bladt, E. M. Zgainsky PLANT DRUG ANALYSIS – A Thin Layer Chromatography Atlas Springer-Verlag 1984
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI CHIMICI - LA CROMATOGRAFIA Classificazione per stato fisico delle fasi e conformazione del supporto: cromatografia liquida (LC): la fase mobile è liquida, la fase stazionaria può
essere solida, liquida o liquida supportata su solido; cromatografia in fase supercritica (SFC): la fase mobile è un fluido
supercritico, la fase stazionaria è una specie organica supportata; gascromatografia (GC): la fase mobile è gassosa, la fase stazionaria è un solido o
un liquido supportato (GLC); cromatografia su colonna: la fase stazionaria è confinata all’interno di una
struttura tubolare; cromatografia planare: la fase stazionaria è distesa su di una superficie piana.
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI CHIMICI - LA CROMATOGRAFIA Classificazione per meccanismo di interazione: cromatografia di ripartizione: si instaura tra le fasi un equilibrio analogo alla
solubilità cromatografia di adsorbimento: si instaura tra le fasi un equilibrio basato su
interazioni aspecifiche tra analiti e struttura molecolare della fase stazionaria (solida)
cromatografia ionica: si instaura tra le fasi un equilibrio basato su interazioni elettrostatiche tra analiti ionici e gruppi funzionali carichi elettricamente sulla fase stazionaria
cromatografia di esclusione dimensionale: si instaura tra le fasi un equilibrio basato sull’analogia dimensionale tra le molecole degli analiti e le cavità della fase stazionaria
es. fase inversa (RP)
es. gel di silice
es. resine a scambio ionico
es. destrani (LH-20, G-20, ecc.)
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI CHIMICI - LA CROMATOGRAFIA La cromatografia strumentale, sia preparativa che analitica, prevede che gli analiti in uscita dalla colonna cromatografica siano rivelati da opportuni dispositivi, detti rivelatori, e rappresentati graficamente su di un tracciato detto cromatogramma.
16.50 17.00 17.50 18.00 18.50 19.00 19.50
500000
1000000
1500000
2000000
2500000
3000000
3500000
4000000
4500000
5000000
Time-->
Abundance
TIC: 90316_01.DSull’asse delle ascisse è rappresentato il tempo trascorso dall ’ inizio dell’eluizione, sull’asse delle ordinate un valore proporzionale all’intensità del segnale elettrico del rivelatore. All’uscita di un analita dalla colonna, il rivelatore produce un picco di segnale che varia nel tempo con andamento gaussiano; il tempo a cui corrisponde il vertice della gaussiana è detto tempo di ritenzione.
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA GASCROMATOGRAFIA
Skoog D. A., Leary J. J. – CHIMICA ANALITICA STRUMENTALE – EdiSES 1995
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA GASCROMATOGRAFIA
Si O Si O Si
R
R
R
R
R
R
R
R
n
lunghezza: 10 – 100 metri diametro: 0.25 – 0.75 mm spessore della fase stazionaria: 5 mµ≤
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA GASCROMATOGRAFIA
http://www.gerstel.com/pdf/TDS_eng.pdf
TDS: Thermal Desorption System CIS: Cooled Injection System
Skoog D. A., Leary J. J. – CHIMICA ANALITICA STRUMENTALE – EdiSES 1995
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
RIVELATORE VANTAGGI SVANTAGGI
FID
(Flame Ionization Detector) universale, economico
distruttivo, aspecifico,
richiede due gas di alimentazione
ECD
(Electron Capture Detector)
specifico per alogenati, non distruttivo, non
richiede gas
radioattivo, specifico
PID
(PhotoIonization Detector) non richiede gas,
parzialmente specifico
distruttivo, parzialmente
specifico
TCD
(Thermal Conductivity Detector) non richiede gas, non
distruttivo poco sensibile
MSD
(Mass Spectrometric Detector) permette
l’identificazione degli analiti senza standard
molto costoso, distruttivo
Skoog D. A., Leary J. J. – CHIMICA ANALITICA STRUMENTALE – EdiSES 1995
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA GASCROMATOGRAFIA – Rivelatore spettrometro di massa (MSD)
Skoog D. A., Leary J. J. – CHIMICA ANALITICA STRUMENTALE – EdiSES 1995
Diverse tipologie di spettrometri di massa possono essere accoppiati alla gascromatografia come rivelatori. Il più diffuso è lo spettrometro di massa a quadrupolo, grazie alle dimensioni ed ai costi relativamente contenuti, ma rivestono grande importanza anche gli spettrometri a settore magnetico ed a tempo di volo.
TABLE 4.1. Common GC / MS Conditions Used for Analysis of Grape Aroma Compounds
GC column Poly(ethylene)glycol (PEG) bound - phase fused - silica capillary (30 m ! 0.25 mm i.d.; 0.25 - µ m fi lm thickness)
Carrier gas He Column head pressure 12 psi Injector Temperature 200 ° C, sample volume injected 0.5 µ L, splitless
injection Oven program 60 ° C Isotherm for 3 min, 2 ° C/min to 160 ° C, 3 ° C/min to 230 ° C,
230 ° C Isotherm for 5 min MS conditions Ionization energy 70 eV, transfer line temperature 280 ° C, SCAN
mode
OH
OH
(E,E)-2,6-Dimethylocta-2,6-dien-2,8-diol
OH
OH
8-Hydroxy-dihydrolinalool
OH
OH
Hydroxy-geraniol
OH
OH
Hydroxy-nerol
030 40 50 60 70 80 90 100 110 120 130
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
24000
30 40 50 60 70 80 90 100 110 120 130 1400
m/z-->
m/z-->m/z-->
m/z-->
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
7000
7500
8000
8500
9000Abundance
AbundanceAbundance
Abundance
43
5357
6477
93
107
97
121
137
31
44 5979
81
9695 109 111
121
55
43
71
84
68
40
31 53
93
83
43
59
69
121136
153111109
154 1751770
100002000030000400005000060000700008000090000
100000110000120000130000140000150000160000170000180000190000200000210000220000
60 80 100 120 140 160 18030
31
53
79
98
107 136
121
93
8169
59
43
40 50 60 70 80 90 100 110 120 130 1400
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
Figure 4.9. The GC/MS – EI (70 eV) mass spectra of principal terpenol and norisopren-oid compounds identifi ed in grape and not reported in the main libraries commercially available.
TABLE 4.1. Common GC / MS Conditions Used for Analysis of Grape Aroma Compounds
GC column Poly(ethylene)glycol (PEG) bound - phase fused - silica capillary (30 m ! 0.25 mm i.d.; 0.25 - µ m fi lm thickness)
Carrier gas He Column head pressure 12 psi Injector Temperature 200 ° C, sample volume injected 0.5 µ L, splitless
injection Oven program 60 ° C Isotherm for 3 min, 2 ° C/min to 160 ° C, 3 ° C/min to 230 ° C,
230 ° C Isotherm for 5 min MS conditions Ionization energy 70 eV, transfer line temperature 280 ° C, SCAN
mode
OH
OH
(E,E)-2,6-Dimethylocta-2,6-dien-2,8-diol
OH
OH
8-Hydroxy-dihydrolinalool
OH
OH
Hydroxy-geraniol
OH
OH
Hydroxy-nerol
030 40 50 60 70 80 90 100 110 120 130
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
24000
30 40 50 60 70 80 90 100 110 120 130 1400
m/z-->
m/z-->m/z-->
m/z-->
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
7000
7500
8000
8500
9000Abundance
AbundanceAbundance
Abundance
43
5357
6477
93
107
97
121
137
31
44 5979
81
9695 109 111
121
55
43
71
84
68
40
31 53
93
83
43
59
69
121136
153111109
154 1751770
100002000030000400005000060000700008000090000
100000110000120000130000140000150000160000170000180000190000200000210000220000
60 80 100 120 140 160 18030
31
53
79
98
107 136
121
93
8169
59
43
40 50 60 70 80 90 100 110 120 130 1400
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
Figure 4.9. The GC/MS – EI (70 eV) mass spectra of principal terpenol and norisopren-oid compounds identifi ed in grape and not reported in the main libraries commercially available.
104 GRAPE AROMA COMPOUNDS
The dichloromethane solution is concentrated to 2 – 3 mL by distil-lation using a 40 - cm length Vigreux column, and fi nally to 200 µ L under a nitrogen fl ow prior to GC/MS analysis . The GC/MS profi le of free aroma compounds of a Muscat grape skin extract is shown in Fig. 4.6 .
4.2.3 Analysis of Glycoside Compounds
The methanolic solution is evaporated to dryness under vacuum at 40 ° C, the residue is dissolved in 5 mL of a citrate – phosphate buffer (pH 5), then it is added to 200 mg of a glycosidic enzyme with strong glycosidase activity (e.g., AR 2000, Gist Brocades) and kept at 40 ° C overnight (15 h). The next day the solution is centrifuged, added to 200 µ L of a 1 - octanol 180 - mg/L solution as an internal standard, and the resulting solution is passed through a 1 - g C 18 cartridge previously activated by passage of 6 - mL dichloromethane, 6 - mL methanol, and 6 - mL water. After cartridge washing with 5 - mL water, the fraction containing the aglycones is eluted with 6 mL of dichloromethane, dehydrated with sodium sulfate, and concentrated to 200 µ L with a nitrogen fl ow before analysis. A last fraction, containing the poten-tially aromatic precursor compounds, is recovered from the cartridge by elution with 5 - mL methanol. The GC/MS profi le of aglycones from hydrolysis of glycoside compounds of a Prosecco grape must is shown in Fig. 4.7 .
Figure 4.6. The GC/MS – EI (70 eV) chromatogram recorded in SCAN mode of free aroma compounds of a Muscat grape skins extract. I.S., internal standard (1 - heptanol); peak 1. linalool; peak 2. trans - pyranlinalool oxide; peak 3. cis - pyranlinalool oxide; peak 4. nerol; peak 5. geraniol; peak 6. Ho - diendiol I; peak 7. Ho - diendiol II; peak 8. hydroxycitronellol; peak 9. 7 - hydroxygeraniol; peak 10. ( E ) - geranic acid.
Abundance
900,000
800,000
700,000
600,000
500,000
400,000
300,000
200,000
100,000
0Time--> 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00
I.S.1
2
3
4
5
6
7
8
9
10
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA GASCROMATOGRAFIA
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LO SPAZIO DI TESTA STATICO
www.microglass.it/3_HAMILTON/3_HAMILTON_SCHEDE/SERIE_1000.htm
CH3SSCH3
CH3SSCH3
bagno termico
spazio di testa
matrice CH3SSCH3
CH3SSCH3
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LO SPAZIO DI TESTA STATICO – SPME (Solid Phase MicroExtraction)
ulceet.com/site30.php
polidimetilsilossano (PDMS) – apolare poliacrilato (PA) – polare carbopack (carbone grafitato) – polarità intermedia carboxen/polidimetilsilossano (CAR/PDMS) – polarità
media e bassa polidimetilsilossano/divinilbenzene (PDMS/DVB) –
apolare e aromatica divinilbenzene/carboxen/polidimetilsilossano (DVB/
CAR/PDMS) – polivalente carbowax/glicole polietilenico – polare carbowax/resina templata (CW/TPR) - polare
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
SPME in matrici acquose La già trattata tecnica di microestrazione in fase solida, molto valida per l’analisi dello spazio di testa statico, è in teoria applicabile anche agli analiti organici in soluzione acquosa.
www2.mst.dk/common/Udgivramme/Frame.asp?http://www2.mst.dk/Udgiv/publikationer/2000/87-7944-147-5/html/bil02.htm
Si tratta di immergere direttamente la fibra nel campione liquido. VANTAGGI: • permette di evidenziare le sostanze meno volatili, • aumenta la sensibilità perché concentra gli analiti. SVANTAGGI: • può adsorbire sostanze fisse che non si desorbono e si decompongono sulla fibra (accorciamento della vita).
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
SBSE (Stir Bar Sorptive Extraction) E’ una tecnica appositamente sviluppata per il campionamento delle sostanze organiche in campioni liquidi; si applica quindi alle stesse problematiche della SPME in matrici acquose, rispetto alla quale tuttavia è più efficiente.
Si tratta di un agitatore magnetico esternamente rivestito di una guaina in materiale adsorbente, normalmente PDMS. L’agitatote, messo in rotazione all’interno di un campione liquido sigillato, adsorbe gli analiti organici fino alla concentrazione di equilibrio. Al termine del campionamento, le sostanze adsorbite possono essere analizzate in GC per desorbimento termico.
www.gerstel.com/en/twister-stir-bar-sorptive-extraction.htm
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LO SPAZIO DI TESTA DINAMICO
Nello spazio di testa dinamico il campione è arricchito dallo spostamento dell’equilibrio verso la fase aeriforme, come conseguenza del principio di Le Châtelier. Gli analiti sono asportati dallo spazio di testa da un flusso di azoto ed intrappolati nelle consuete fasi solide adsorbenti. LA SENSIBILITA’ RISPETTO A L L O S P A Z I O D I T E S T A S T A T I C O E ’ NOTEVOLMENTE INCREMENTATA: POSSONO ESSERE CAMPIONATI SVARIATI LITRI DI SPAZIO DI TESTA ANCHE PER CAMPIONI DI PICCOLO VOLUME. Se il campione è attraversato dal flusso di campionamento, il contributo all’arricchimento potrebbe derivare non solo dal principio di Le Châtelier ma anche dall’innalzamento della tensione di vapore degli analiti (vedi distillazione in corrente di vapore). In campioni liquidi il metodo è noto come “purge and trap”.
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI SENSORIALI AROMA ORTONASALE – La misura sensoriale dell’odore si attua tramite la valutazione di un “panel” di analisti selezionati. Qualora lo scopo dell’analisi fosse la misura della soglia di percezione olfattiva di un campione aeriforme, il panel si dovrebbe avvalere di un olfattometro a diluizione dinamica.
Il campione, all’interno di sacchetti in Nalophan, viene proposto al panel a concentrazione crescente; i volontari segnalano con un pulsante la percezione dell’odore, evitando di segnalare i “bianchi” casuali introdotti dal programma. Il risultato è una c o n c e n t r a z i o n e d ’ o d o r e , o t t e n u t a statisticamente.
http://www.ecoma.de/en/index_frameset.php?id=198
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI SENSORIALI AROMA ORTONASALE E RETRONASALE – Qualora lo scopo dell’analisi fosse una valutazione qualitativa dell’odore, il panel potrebbe procedere anche senza olfattometro, scomponendo mentalmente la percezione sensoriale in componenti descrivibili con altrettanti aggettivi detti descrittori. I descrittori e le relative intensità sono normalmente rappresentate in un grafico radiale, a dare un poligono la cui forma identifica sensorialmente il campione.
LO STESSO PROCEDIMENTO SI APPLICA A QUALUNQUE ANALISI SENSORIALE, IN PARTICOLARE AL SAPORE.
www.beverfood.com/v2/modules/smartsection/item.php?itemid=127
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
MEODI COMBINATI – IL NASO ELETTRONICO
IL NASO ELETTRONICO PERMETTE DI ASSOCIARE UN’EMISSIONE ODOROSA A D U N A S O R G E N T E , A L L ’ I N T E R N O D I U N G RU P P O D I C A M P I O N I DIFFERENZIATI.
www.alibaba.com/product-free/10822337/PEN_II_GAS_Sensor_Array_With.html
Resina di pino
basilico A
0
200
400
600
800
1000
1200
0.0 2.0 4.0 6.0 8.0 10.0
tempo (min)
mV
cromatogramma aromagramma
solfuro Erba tagliata
muffa, erbaceo
Terra bagnata
Agrumato, menta
balsamico
Sgradevole, acre
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
METODI COMBINATI La gascromatografia-olfattometria è una tecnica che combina la separazione gascromatografica delle sostanze volatili alla possibilità di percepirne l’odore in tempo reale. L’analista segnala la percezione con un pulsante, generando un grafico detto aromagramma che può essere sovrapposto al cromatogramma.
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA CROMATOGRAFIA LIQUIDA AD ALTE PRESTAZIONI (HPLC)
Skoog D. A., Leary J. J. – CHIMICA ANALITICA STRUMENTALE – EdiSES 1995
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA CROMATOGRAFIA LIQUIDA AD ALTE PRESTAZIONI (HPLC)
RIVELATORE UV-VIS
DAD (Diode Array Detector)
MS RID (Refractive Index Detector)
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
LA CROMATOGRAFIA LIQUIDA AD ALTE PRESTAZIONI (HPLC)
OSi CH3CH3
OSi CH3CH3
F
F
FF
F
OSi CH3CH3
OSi CH3CH3
F
F F
F
F
OSi CH3CH3
OSi CH3CH3
NH2
OSi
OO
OH
OSi CH3CH3
CN
OSi CH3CH3
OSiOO
OSi CH3CH3 O
Si CH3CH3
P
OSi
OP
C8
C18
X3
IBD
C18 acquoso
ammino
fenile
bifenile
Fase diretta
PFP
PFP propile fenil propile
ciano
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
SPE (Solid Phase Extraction)
www.biotage.com/DynPage.aspx?id=35833
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
Chemical components contributing to flavor
Grape and wine flavor is complex and many di!erent sensorymodalities and chemical compounds influence flavor percep-tion (Table 1).5 However, aroma (smell) is the major contri-butor to overall flavor perception and this review will focuslargely on the volatile aroma compounds that contribute togrape and wine flavor.The basic processes for producing red and white wines are
shown in Fig. 1, with the main distinction being that red winesare fermented with the skins present so that more chemicalcomponents from the skins (e.g., anthocyanins, polyphenols,flavor compounds) are extracted into the juice/wine during thefermentation. The complex aromas of the final wine aretherefore derived from the grape, the yeast fermentation(typically Saccharomyces cerevisiae), any secondary microbialfermentations that occur, and the aging/storage conditions.There are clear sensory di!erences in the aromas of most
grape varieties, however the overall volatile composition ofmost varieties is similar, with the varietal aroma derivinglargely from di!erences in relative ratios of many volatilecompounds, as further discussed below. In only a few caseshave individual character impact compounds (see Fig. 2) beenidentified and associated with specific varietal aroma attributes(Table 2) (an impact compound is a single compound thatconveys the named flavor6). Most of the impact compounds
that have been identified are present at low concentrations ingrapes and wines, however because of their very low (ng L!1)sensory thresholds they can have a large impact on the overallgrape/wine aroma.In general, the fermentation-derived volatiles make up the
largest percentage of the total aroma composition of wine.Fermentation by Saccharomyces cerevisiae leads to formationof many alcohols (predominantly ethanol and the C3–C5
straight chain and branched n-alcohols, and 2-phenylethanol)
Fig. 1 White and red wine production. 1Indicates steps that are optional and/or not done on every variety or wine style. 2If skins are removed
from red grape must, a blush or rose juice is obtained; color is dependant on grape varietal and contact time with skins.
Table 1 Sensory modalities and selected chemical components con-tributing to grape and wine flavor
Sensory modality AttributeExample chemicalcompounds in wine
Taste Sweet Glucose, fructose,glycerol, ethanol
Sour Tartaric acidSalty Sodium chloride,
potassium chlorideBitter Catechin
Smell/aroma Floral, lily-of-the valleyaroma
Linalool
Banana-like aroma Isoamyl acetateChemesthesis Mouth-warming/heat EthanolTactile Viscosity Glycerol,
polysaccharidesAstringency Tannins
Vision Red Malvidin-3-glucoside
This journal is "c The Royal Society of Chemistry 2008 Chem. Soc. Rev., 2008, 37, 2478–2489 | 2479
Pub
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n 12
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ust
2008
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by U
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4.
View Article Online
Wine flavor: chemistry in a glass
Pavla Polaskova, Julian Herszage and Susan E. Ebeler*
Received 13th May 2008
First published as an Advance Article on the web 12th August 2008
DOI: 10.1039/b714455p
Although hundreds of chemical compounds have been identified in grapes and wines, only a few
compounds actually contribute to sensory perception of wine flavor. This critical review focuses
on volatile compounds that contribute to wine aroma and provides an overview of recent
developments in analytical techniques for volatiles analysis, including methods used to identify the
compounds that make the greatest contributions to the overall aroma. Knowledge of volatile
composition alone is not enough to completely understand the overall wine aroma, however, due
to complex interactions of odorants with each other and with other nonvolatile matrix
components. These interactions and their impact on aroma volatility are the focus of much
current research and are also reviewed here. Finally, the sequencing of the grapevine and yeast
genomes in the past B10 years provides the opportunity for exciting multidisciplinary studies
aimed at understanding the influences of multiple genetic and environmental factors on grape and
wine flavor biochemistry and metabolism (147 references).
Introduction
From Pasteur’s discoveries of the role of microorganisms infermentation and his studies on the analytical separations ofchiral organic acids in grape juice1,2 to Kepler’s developmentof early calculus theories to measure wine barrel volumes,3
grapes and wines have provided a rich basis for many dis-coveries that have had fundamental impacts on mathematics,microbiology, and chemistry over the past several centuries.The chemistry of grape and wine flavor, in particular, has beenthe focus of much research due to the complexity of thevolatile aromas that contribute to flavor and the nuancedvariations that arise from di!erent grape varieties, growingregions, and vintage years. In the 19th and early part of the20th centuries, much of the focus of wine flavor chemistryresearch was on measuring the major components that
contribute to taste and aroma (ethanol, organic acids, sugars),the compounds associated with protecting wine quality,4 andon those compounds associated with ‘‘defects’’ or undesirablearomas such as acetic acid (which results in a vinegar aroma).As fermentation technology improved, the incidence of defectsdecreased, and in the mid-1900s flavor chemists turned theirfocus toward understanding the chemical components thatcontribute to specific sensory attributes associated withdi!erent grapes and wines and di!erent wine styles (e.g., tablewines, port, Sauternes-style wines, etc.). These studies wereenabled by important advances in the development of gaschromatography (GC) in the 1950s and the introduction ofcommercial capillary GC columns in the 1980s. In this reviewwe will first summarize the components that contribute to wineflavor, focusing on aroma components, then we present anoverview of more recent developments in analytical techniquesfor the analysis of wine volatiles, methods for relatingchemical composition to sensory perception of aroma, andthe emerging role of genomics and proteomics for under-standing aroma development in grapes.
Department of Viticulture and Enology, University of California,Davis, One Shields Avenue, Davis, CA 95616, USA.E-mail: [email protected]; Fax: +1 530-752-0382;Tel: +1 530-752-0696
Pavla Polaskova earned her PhD degreein Analytical Chemistry in 2003 from theMasaryk University Brno in the CzechRepublik. Later she worked for two yearsas a postdoctoral scholar in the ChemistryDepartment at the University ofCalifornia Davis. Three years ago shejoined the Viticulture and EnologyDepartment in UC Davis as a post-doctoral scholar, where she is focusingon aroma compounds and flavorinteractions in wine.
In 2001 Julian Herszage earned his PhDdegree in Chemistry from the Universidadde Buenos Aires in Argentina. Followinghis degree he worked for two years as apostdoctoral scholar at the Scripps Insti-tution of Oceanography in San Diego,California. He joined the Viticulture andEnology Department in UC Davis as apostdoctoral scholar in 2006. His researchfocuses on detection and quantification ofvolatile sulfur compounds in wine andunderstanding the factors that influenceformation of these important wine aromacompounds.
Susan Ebeler is a professor in the depart-ment of Viticulture and Enology at UCDavis. Her research is focused on thedevelopment and application of analyticalchemistry techniques to study grape andwine flavor chemistry, understanding thephysico-chemical interactions of flavorswith nonvolatile food and beverage com-ponents, and elucidating the chemicalmechanisms for observed health e!ectsof grape and wine components. She tea-ches undergraduate and graduate classeson Grape and Wine Analysis and FlavorChemistry of Foods and Beverages.
2478 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is !c The Royal Society of Chemistry 2008
CRITICAL REVIEW www.rsc.org/csr | Chemical Society Reviews
Publi
shed
on 1
2 A
ugust
2008. D
ow
nlo
aded
by U
niv
ersi
ta d
i P
avia
on 2
4/0
9/2
013 1
2:4
9:1
4.
View Article Online / Journal Homepage / Table of Contents for this issue
Chemical components contributing to flavor
Grape and wine flavor is complex and many di!erent sensorymodalities and chemical compounds influence flavor percep-tion (Table 1).5 However, aroma (smell) is the major contri-butor to overall flavor perception and this review will focuslargely on the volatile aroma compounds that contribute togrape and wine flavor.The basic processes for producing red and white wines are
shown in Fig. 1, with the main distinction being that red winesare fermented with the skins present so that more chemicalcomponents from the skins (e.g., anthocyanins, polyphenols,flavor compounds) are extracted into the juice/wine during thefermentation. The complex aromas of the final wine aretherefore derived from the grape, the yeast fermentation(typically Saccharomyces cerevisiae), any secondary microbialfermentations that occur, and the aging/storage conditions.There are clear sensory di!erences in the aromas of most
grape varieties, however the overall volatile composition ofmost varieties is similar, with the varietal aroma derivinglargely from di!erences in relative ratios of many volatilecompounds, as further discussed below. In only a few caseshave individual character impact compounds (see Fig. 2) beenidentified and associated with specific varietal aroma attributes(Table 2) (an impact compound is a single compound thatconveys the named flavor6). Most of the impact compounds
that have been identified are present at low concentrations ingrapes and wines, however because of their very low (ng L!1)sensory thresholds they can have a large impact on the overallgrape/wine aroma.In general, the fermentation-derived volatiles make up the
largest percentage of the total aroma composition of wine.Fermentation by Saccharomyces cerevisiae leads to formationof many alcohols (predominantly ethanol and the C3–C5
straight chain and branched n-alcohols, and 2-phenylethanol)
Fig. 1 White and red wine production. 1Indicates steps that are optional and/or not done on every variety or wine style. 2If skins are removed
from red grape must, a blush or rose juice is obtained; color is dependant on grape varietal and contact time with skins.
Table 1 Sensory modalities and selected chemical components con-tributing to grape and wine flavor
Sensory modality AttributeExample chemicalcompounds in wine
Taste Sweet Glucose, fructose,glycerol, ethanol
Sour Tartaric acidSalty Sodium chloride,
potassium chlorideBitter Catechin
Smell/aroma Floral, lily-of-the valleyaroma
Linalool
Banana-like aroma Isoamyl acetateChemesthesis Mouth-warming/heat EthanolTactile Viscosity Glycerol,
polysaccharidesAstringency Tannins
Vision Red Malvidin-3-glucoside
This journal is "c The Royal Society of Chemistry 2008 Chem. Soc. Rev., 2008, 37, 2478–2489 | 2479
Pu
bli
shed
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gu
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00
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/09
/20
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:49
:14
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View Article Online
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
Wine flavor: chemistry in a glass
Pavla Polaskova, Julian Herszage and Susan E. Ebeler*
Received 13th May 2008
First published as an Advance Article on the web 12th August 2008
DOI: 10.1039/b714455p
Although hundreds of chemical compounds have been identified in grapes and wines, only a few
compounds actually contribute to sensory perception of wine flavor. This critical review focuses
on volatile compounds that contribute to wine aroma and provides an overview of recent
developments in analytical techniques for volatiles analysis, including methods used to identify the
compounds that make the greatest contributions to the overall aroma. Knowledge of volatile
composition alone is not enough to completely understand the overall wine aroma, however, due
to complex interactions of odorants with each other and with other nonvolatile matrix
components. These interactions and their impact on aroma volatility are the focus of much
current research and are also reviewed here. Finally, the sequencing of the grapevine and yeast
genomes in the past B10 years provides the opportunity for exciting multidisciplinary studies
aimed at understanding the influences of multiple genetic and environmental factors on grape and
wine flavor biochemistry and metabolism (147 references).
Introduction
From Pasteur’s discoveries of the role of microorganisms infermentation and his studies on the analytical separations ofchiral organic acids in grape juice1,2 to Kepler’s developmentof early calculus theories to measure wine barrel volumes,3
grapes and wines have provided a rich basis for many dis-coveries that have had fundamental impacts on mathematics,microbiology, and chemistry over the past several centuries.The chemistry of grape and wine flavor, in particular, has beenthe focus of much research due to the complexity of thevolatile aromas that contribute to flavor and the nuancedvariations that arise from di!erent grape varieties, growingregions, and vintage years. In the 19th and early part of the20th centuries, much of the focus of wine flavor chemistryresearch was on measuring the major components that
contribute to taste and aroma (ethanol, organic acids, sugars),the compounds associated with protecting wine quality,4 andon those compounds associated with ‘‘defects’’ or undesirablearomas such as acetic acid (which results in a vinegar aroma).As fermentation technology improved, the incidence of defectsdecreased, and in the mid-1900s flavor chemists turned theirfocus toward understanding the chemical components thatcontribute to specific sensory attributes associated withdi!erent grapes and wines and di!erent wine styles (e.g., tablewines, port, Sauternes-style wines, etc.). These studies wereenabled by important advances in the development of gaschromatography (GC) in the 1950s and the introduction ofcommercial capillary GC columns in the 1980s. In this reviewwe will first summarize the components that contribute to wineflavor, focusing on aroma components, then we present anoverview of more recent developments in analytical techniquesfor the analysis of wine volatiles, methods for relatingchemical composition to sensory perception of aroma, andthe emerging role of genomics and proteomics for under-standing aroma development in grapes.
Department of Viticulture and Enology, University of California,Davis, One Shields Avenue, Davis, CA 95616, USA.E-mail: [email protected]; Fax: +1 530-752-0382;Tel: +1 530-752-0696
Pavla Polaskova earned her PhD degreein Analytical Chemistry in 2003 from theMasaryk University Brno in the CzechRepublik. Later she worked for two yearsas a postdoctoral scholar in the ChemistryDepartment at the University ofCalifornia Davis. Three years ago shejoined the Viticulture and EnologyDepartment in UC Davis as a post-doctoral scholar, where she is focusingon aroma compounds and flavorinteractions in wine.
In 2001 Julian Herszage earned his PhDdegree in Chemistry from the Universidadde Buenos Aires in Argentina. Followinghis degree he worked for two years as apostdoctoral scholar at the Scripps Insti-tution of Oceanography in San Diego,California. He joined the Viticulture andEnology Department in UC Davis as apostdoctoral scholar in 2006. His researchfocuses on detection and quantification ofvolatile sulfur compounds in wine andunderstanding the factors that influenceformation of these important wine aromacompounds.
Susan Ebeler is a professor in the depart-ment of Viticulture and Enology at UCDavis. Her research is focused on thedevelopment and application of analyticalchemistry techniques to study grape andwine flavor chemistry, understanding thephysico-chemical interactions of flavorswith nonvolatile food and beverage com-ponents, and elucidating the chemicalmechanisms for observed health e!ectsof grape and wine components. She tea-ches undergraduate and graduate classeson Grape and Wine Analysis and FlavorChemistry of Foods and Beverages.
2478 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is !c The Royal Society of Chemistry 2008
CRITICAL REVIEW www.rsc.org/csr | Chemical Society Reviews
Publi
shed
on 1
2 A
ugust
2008. D
ow
nlo
aded
by U
niv
ersi
ta d
i P
avia
on 2
4/0
9/2
013 1
2:4
9:1
4.
View Article Online / Journal Homepage / Table of Contents for this issue
Chemical components contributing to flavor
Grape and wine flavor is complex and many di!erent sensorymodalities and chemical compounds influence flavor percep-tion (Table 1).5 However, aroma (smell) is the major contri-butor to overall flavor perception and this review will focuslargely on the volatile aroma compounds that contribute togrape and wine flavor.The basic processes for producing red and white wines are
shown in Fig. 1, with the main distinction being that red winesare fermented with the skins present so that more chemicalcomponents from the skins (e.g., anthocyanins, polyphenols,flavor compounds) are extracted into the juice/wine during thefermentation. The complex aromas of the final wine aretherefore derived from the grape, the yeast fermentation(typically Saccharomyces cerevisiae), any secondary microbialfermentations that occur, and the aging/storage conditions.There are clear sensory di!erences in the aromas of most
grape varieties, however the overall volatile composition ofmost varieties is similar, with the varietal aroma derivinglargely from di!erences in relative ratios of many volatilecompounds, as further discussed below. In only a few caseshave individual character impact compounds (see Fig. 2) beenidentified and associated with specific varietal aroma attributes(Table 2) (an impact compound is a single compound thatconveys the named flavor6). Most of the impact compounds
that have been identified are present at low concentrations ingrapes and wines, however because of their very low (ng L!1)sensory thresholds they can have a large impact on the overallgrape/wine aroma.In general, the fermentation-derived volatiles make up the
largest percentage of the total aroma composition of wine.Fermentation by Saccharomyces cerevisiae leads to formationof many alcohols (predominantly ethanol and the C3–C5
straight chain and branched n-alcohols, and 2-phenylethanol)
Fig. 1 White and red wine production. 1Indicates steps that are optional and/or not done on every variety or wine style. 2If skins are removed
from red grape must, a blush or rose juice is obtained; color is dependant on grape varietal and contact time with skins.
Table 1 Sensory modalities and selected chemical components con-tributing to grape and wine flavor
Sensory modality AttributeExample chemicalcompounds in wine
Taste Sweet Glucose, fructose,glycerol, ethanol
Sour Tartaric acidSalty Sodium chloride,
potassium chlorideBitter Catechin
Smell/aroma Floral, lily-of-the valleyaroma
Linalool
Banana-like aroma Isoamyl acetateChemesthesis Mouth-warming/heat EthanolTactile Viscosity Glycerol,
polysaccharidesAstringency Tannins
Vision Red Malvidin-3-glucoside
This journal is "c The Royal Society of Chemistry 2008 Chem. Soc. Rev., 2008, 37, 2478–2489 | 2479
Pu
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Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
HIGHER ALCOHOLS AND ESTERS FORMED FROM YEASTS 121
TABLE 5.2. Wine Volatiles Detectable by HS – SPME Using a CAR – PDMS – DVB Fiber and Their Principal m / z Signals a
Compound m/z Compound m/z
( E ) - 2 - Nonenal 70;41;83 Ethyl octanoate 88;101;127 ( E,E ) - 2,4 - Decadienal 81;41;39 Ethyl propanoate 29;57;27 1,1,6 - Trimethyl - 1,2 -
dihydronaphthalene 157;142;172 Ethyl lactate 45;29;75
1 - Hexanol 56;43;69 Geranyl ethylether 69;93;121 1 - Octen - 3 - ol 72;57;85 Hexanoic acid 60;73,87 2 - Methyl - 1 - butanol 57;41;70 Hexyl acetate 43;56;61 2 - Octanone 43;58;71 Isoamyl acetate 43;70;55 2 - Phenylethanol 91;92;122 Isoamyl alcohol 55;42;70 2 - Phenylethyl acetate 104;43;91 Isoamyl octanoate 70;127;43 3 - Methyl - 1 - butanol 55;42;70 Isobutyl alcohol 43;41;42 Acetic acid 43;45;60 Linalool 71;93;55 cis - 3 - Hexenol 67;41;55 Linalyl ethylether b 71;43;99 cis - Furanlinalool oxide 59;94;111 Methyl decanoate 74;87;155 Decanoic acid 60;73;129 Methyl heptanoate
(I.S.) 74;43;87
Diethylsuccinate 101;129;55 Methyl hexanoate 74;87;99 Ethyl 2 - methylbutanoate 102;85;74 Methyl octanoate 74;87;127 Ethyl 3 - hexenoate 69;41;68 Octanoic acid 60;73;101 Ethyl 9 - decenoate 41;55;88 Propanol 31;29;42 Ethyl acetate 61;70;73 trans - Furanlinalool
oxide 59;43;68
Ethyl butanoate 71;43;88 Vitispiranes 192;177;121 Ethyl decanoate 88;61;155 ! - Ionone 121;93;192 Ethyl dodecanoate 88;101;183 ! - Terpineol 59;93;136 Ethyl hexanoate 88;99;60 " - Damascenone 69;121;190 Ethyl isobutanoate 43;29;71 " - Ionone 177;178;135 Ethyl isovalerate 29;57;88 Furfural 96;95;39
a EI 70 eV. Versini et al., 2008 ; Ferreira and de Pinho, 2003 ; Bosch - Fust é , 2007. b Data kindly provided by Prof. R. Di Stefano.
TABLE 5.3. Wine Volatiles Detectable by HS – SPME Using a 100 - µ m PDMS Fiber and Their Principal m / z Signals a
Compound m/z Compound m/z
( E ) - 2 - Nonenal 70;41;83 Ethyl hexanoate 88;99;60 ( E ) - Cinnamaldehyde 131;103;51 Ethyl
isobutanoate 43;29;71
( E ) - " - Ocimene 93;91;73 Ethyl isovalerate 29;57;88 ( E,E ) - 2,4 - Decadienal 81;41;39 Ethyl lactate 45;29;75 ( Z ) - 3 - Hexen - 1 - ol 67;41;55 Ethyl nonanoate 88;101;73 ( Z ) - " - Ocimene 93;91;79 Ethyl octanoate 88;101;127 1,2 - Dihydro - 1,1,6 -
trimethylnaphthalene 157;142;172 Ethyl propanoate 29;57;27
1,3 - Butanediol 43;45;57 Ethyl sorbate 67;95;41
HIGHER ALCOHOLS AND ESTERS FORMED FROM YEASTS 119
example, by synthesis of ethyl esters by reaction of the corresponding organic acid with d 5 - ethanol (Siebert et al., 2005 ). Polydimethylsiloxane (PDMS) fi bers have high affi nity for high molecular weight nonpolar compounds, such as ethyl esters and higher alcohols (Bonino et al., 2003 , Vianna and Ebeler, 2001 ; Mart í et al., 2003 ), a mixed - fi ber carbowax – divinylbenzene (CW/DVB) for C 6 and higher aliphatic alcohols and monoterpenols (Bonino et al., 2003 ). The triphase CAR/PDMS/DVB fi ber is suitable for sampling of both lower molecular weight and more polar compounds (Howard et al., 2005 ), overcoming the lack of selectiv-ity toward some compounds of the one - or two - phase fi bers (Ferreira and de Pinho, 2003 ). The HS – SPME – GC/MS chromatogram relative to analysis of wine volatiles by triphase fi ber is shown in Fig. 5.1 , the experi-mental conditions are reported in Table 5.1 . A list of wine volatiles detectable by this method is reported in Table 5.2 .
Figure 5.1. HS (headspace) – SPME – GC/MS chromatogram recorded in the analysis of a Gew ü rztraminer wine volatiles performed using a CAR – PDMS – DVB fi ber and the experimental conditions reported in Table 5.1 . ( 1 ) ethyl hexanoate; ( 2 ) 2 - and 3 - methyl - 1 - butanol (isoamyl alcohols); ( 3 ) ethyl lactate; ( 4 ) 1 - hexanol; ( 5 ) ethyl octanoate; ( 6 ) 1 - heptanol (internal standard); ( 7 ) benzaldehyde; ( 8 ) linalool; ( 9 ) ethyl decanoate; ( 10 ) diethyl succinate; ( 11 ) ! - terpineol; ( 12 ) 2 - phenylethyl acetate; ( 13 ) 2 - phenylethanol; ( 14 ) octanoic acid.
1
2
34
5
6
78
9
10
11
1314
12
Abundance
8,000,000
8,500,000
7,500,000
7,000,000
6,500,000
6,000,000
5,500,000
5,000,000
4,500,000
4,000,000
3,500,000
3,000,000
2,500,000
2,000,000
1,500,000
1,000,000
500,000
0Time--> 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 (min)
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali TABLE 5.8. Mean Contents of Carbonyl Compounds Identifi ed in Chardonnay and Cabernet Sauvignon Wines a and Grappa Samples b
Compound ( µ g/L) c
Wine Grappa
Cabernet Sauvignon Chardonnay Cabernet Sauvignon Chardonnay Before MLF After MLF Before MLF After MLF ( µ g/100 mL a.e.) ( µ g/100 mL a.e.)
( E ) - 2 - Hexenal 3.43 0.58 0.82 1.09 71.2 73.3 ( E ) - 2 - Nonenal trace 0.18 0.18 0.29 8.7 12.8 ( E ) - 2 - Octenal n.f. 4.4 ( E ) - 2 - Pentenal 15.7 28.5 ( E,E ) - 2,6 - Nonadienal 13.78 0.27 n.f. n.f. 2,3 - Butanedione 250 2820 50 940 179.2 189.4 3 - Hydroxy - 2 - butanone 1620 4560 5030 10910 892.1 384.9 Acetaldehyde (mg/L) 52.01 5.02 46.54 67.04 33.2 20.8 Benzaldehyde 1117.2 699.5 Butyraldehyde 12.36 19.99 8.48 5.08 Decanal 0.34 1.56 1.84 4.13 Glycolaldehyde d 48.43 391.6 38.51 110.87 6.1 6.0 Glyoxal 41.33 106.01 49.11 95.92 0.2 0.1 Heptanal 3.36 0.56 0.35 1.99 52.3 116.2 Hexanal 94.63 91.67 10.79 89.94 1093.5 1563.2 Isovaleraldehyde+ 50.6 148.6 2 - Methylbutyraldehyde 25.69 45.51 45.85 24.46 11.5 18.2 Methylglyoxal d 10.96 14.37 34.73 71.55 0.3 0.2 Nonanal 1.30 1.85 1.05 2.92 11.2 32.5 Octanal 0.82 0.77 0.39 0.80 4.7 13.6 Propanal 53.8 90.4 Vanillin 1.30 1.8
a Before and after Malolactic fermentation. b Not found, n.f., a.e., anhydrous ethanol. c Amounts expressed as internal standard o - chlorobenzaldehyde (I.S.). d Quantifi ed on basis of one of the two PFBOA syn – anti oxime peaks.
132
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali 98 GRAPE AROMA COMPOUNDS
Figure 4.1. Principal monotepenes in grape and wine. ( 1 ) The cis - and trans - linalool oxide (5 - ethenyltetrahydro - ! , ! ,5 - trimethyl - 2 - furanmethanol) (furanic form); ( 2 ) lin-alool (3,7 - dimethyl - 1,6 - octadien - 3 - ol); ( 3 ) ! - terpineol ( ! , ! ,4 - trimethyl - 3 - cycloexene - 1 - methanol); ( 4 ) cis - and trans - ocimenol [( E - and Z - )2,6 - dimethyl - 5,7 - octen - 2 - ol]; ( 5 ) cis - and trans - linalool oxide (6 - ethenyltetrahydro - 2,2,6 - trimethyl - 2H - pyran - 3 - ol) (pyranic form); ( 6 ) hydroxycitronellol (3,7 - dimethyloctane - 1,7 - diol); ( 7 ) 8 - hydro-xydihydrolinalool (2,6 - dimethyl - 7 - octene - 1,6 - diol); ( 8 ) 7 - hydroxygeraniol [( E ) - 3,6 - dimethyl - 2 - octene - 1,7 - diol]; ( 9 ) 7 - hydroxynerol [( Z ) - 3,6 - dimethyl - 2 - octene - 1,7 - diol]; ( 10 ) cis - and trans - 8 - hydroxylinalool [( E - and Z - ) 2,6 - dimethyl - 2,7 - octadiene - 1,6 - diol];
OOH
521OH
4OH
O
HOHO
3
* **
*
**
OH
7
OH
6
OH
OH
8 9 10
OH
OHOH
OH
OH
OH**
*
*
OH
14
OH
15
*
13
OH
11
OH
OH
12
OH
OH
**
*
O
OOH
O*
O
O
OH
OH
2019181761
**
**
21
OH
OH
*
O
OH
O
OH
OHOH
OH
*
O
*
*
22 23 24 25
*
*
OH
OH
OH
26
OH
*
27
OH
28
*
*
100 GRAPE AROMA COMPOUNDS
Figure 4.2. Principal norisoprenoid compounds in grape and wine. ( 29 ) TDN (1,1,6 - trimethyl - 1,2 - dihydronaphthalene); ( 30 ) ! - damascone; ( 31 ) ! - damascenone; ( 32 ) vom-ifoliol; ( 33 ) dihydrovomifoliol; ( 34 ) 3 - hydroxy - ! - damascone; ( 35 ) 3 - oxo - " - ionol; ( 36 ) 3 - hydroxy - 7,8 - dihydro - ! - ionol; ( 37 ) " - ionol; ( 38 ) ! - ionol; ( 39 ) " - ionone; ( 40 ) ! - ionone; ( 41 ) actinidols; ( 42 ) vitispiranes (spiro [4.5] - 2,10,10 - trimethyl - 6 - methylene - 1 - oxa - 7 - decene); ( 43 ) Riesling acetal (2,2,6 - tetramethyl - 7,11 - dioxatricyclo[6.2.1.0 1,6 ]undec - 4 - ene).
OO
O
OH
OH
O
OH
OH
3332313029
* * **
OO
O*
** **
O
OH O
OH
OH
OH
363534
**
*
*
O
OH OH
3837
39 40 41 42 43
*
** *
O
O OH**
*
Figure 4.3. Principal fl avoring benzenoid compounds in grape. ( 44 ) zingerone; ( 45 ) zingerol; ( 46 ) vanillin; ( 47 ) ethyl vanillate; and ( 48 ) methyl salicylate.
HO HO
OCH3
CH3
O
OCH3
CH3
OH
OH
OCH3
O
OH
OCH3
O O CH3 O
OH
OH3C
4544
484746
reported in Fig. 4.3 (Williams et al., 1983; 1989 ; Winterhalter et al., 1990 ; L ó pez et al., 2004 ).
3 - Alkyl - 2 - methoxypyrazines are compounds present in skin, pulp, and bunch stems of grape, and contribute with very characteristic vegetative, herbaceous, bell pepper, or earthy notes to the aroma of Cabernet Sauvignon , Sauvignon blanc , Semillon , and other wines
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
100 GRAPE AROMA COMPOUNDS
Figure 4.2. Principal norisoprenoid compounds in grape and wine. ( 29 ) TDN (1,1,6 - trimethyl - 1,2 - dihydronaphthalene); ( 30 ) ! - damascone; ( 31 ) ! - damascenone; ( 32 ) vom-ifoliol; ( 33 ) dihydrovomifoliol; ( 34 ) 3 - hydroxy - ! - damascone; ( 35 ) 3 - oxo - " - ionol; ( 36 ) 3 - hydroxy - 7,8 - dihydro - ! - ionol; ( 37 ) " - ionol; ( 38 ) ! - ionol; ( 39 ) " - ionone; ( 40 ) ! - ionone; ( 41 ) actinidols; ( 42 ) vitispiranes (spiro [4.5] - 2,10,10 - trimethyl - 6 - methylene - 1 - oxa - 7 - decene); ( 43 ) Riesling acetal (2,2,6 - tetramethyl - 7,11 - dioxatricyclo[6.2.1.0 1,6 ]undec - 4 - ene).
OO
O
OH
OH
O
OH
OH
3332313029
* * **
OO
O*
** **
O
OH O
OH
OH
OH
363534
**
*
*
O
OH OH
3837
39 40 41 42 43
*
** *
O
O OH**
*
Figure 4.3. Principal fl avoring benzenoid compounds in grape. ( 44 ) zingerone; ( 45 ) zingerol; ( 46 ) vanillin; ( 47 ) ethyl vanillate; and ( 48 ) methyl salicylate.
HO HO
OCH3
CH3
O
OCH3
CH3
OH
OH
OCH3
O
OH
OCH3
O O CH3 O
OH
OH3C
4544
484746
reported in Fig. 4.3 (Williams et al., 1983; 1989 ; Winterhalter et al., 1990 ; L ó pez et al., 2004 ).
3 - Alkyl - 2 - methoxypyrazines are compounds present in skin, pulp, and bunch stems of grape, and contribute with very characteristic vegetative, herbaceous, bell pepper, or earthy notes to the aroma of Cabernet Sauvignon , Sauvignon blanc , Semillon , and other wines
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
and esters (predominantly ethyl acetate and isoamyl acetate).The ester 3-methylbutyl acetate appears to be an importantaroma component of many varieties18,27 however, in general,most of the fermentation-derived compounds have relativelyhigh sensory thresholds and therefore do not individuallycontribute significantly to the aroma of wines. Combined,however, their impact may be important as shown in modelsystems.28
In addition to the primary yeast fermentation, some wines(e.g., Chardonnay in the US) undergo a secondary microbialfermentation with Oenococcus oeni (also called malolacticfermentation) and as a result may contain high concentrations
of diacetyl (2,3-butanedione), which contributes a butteryaroma to these wines. The e!ects of fermentation conditionsand reviews of the biochemical processes involved information of the fermentation-derived aromas have beenreviewed by others.29–31
Finally, changes in concentrations of many aromacompounds occur during storage and wine aging. Many winesare stored or fermented in oak barrels and one of the mostimportant volatiles extracted from the wood is b-methyl-g-octalactone (known as oak- or whiskey-lactone) which con-tributes a woody, oaky, coconut-like aroma to the wine. Thiscompound occurs as two isomers, cis- and trans-, and likemany isomeric compounds, the sensory properties are depen-dent on the isomeric structure. As reviewed by Waterhouseand Towey,32 the cis-oak lactone isomer has an aromathreshold reported as 92 mg L!1, compared to 460 mg L!1
for the trans-isomer and the ratio of the two isomers varieswith oak species and origin. Interestingly, several studies haveshown that the wood can also adsorb some aroma compounds(2-phenylethanol, ethyl decanoate)33–35 changing their concen-tration in solution. These adsorption reactions appear to be afunction of the ratio of wood surface area/solution volumeand are driven by acid–base and polar characteristics of thewood rather than solubility and hydrophobicity of the studiedaroma compounds.33 Wines can also be fermented and aged instainless steel tanks leading to wines that have simpler sensoryproperties mostly due to the lack of the compounds found inwine aged in oak barrels such as lactones and some phenoliccompounds.36,37
In addition to extraction of flavor compounds from oak,chemical and microbial (e.g., Acetobacter) oxidative reactionscan make significant contributions to the flavor of aged winesas a result of formation of compounds such as acetaldehyde(nutty, sherry-like aroma) and acetic acid (vinegar aroma).While acetaldehyde can contribute desirable characteristicaromas to aged wines and Sherries, if oxidative reactions areuncontrolled they can lead to very high concentrations ofacetaldehyde and acetic acid and the overall sensory impactis undesirable.
Fig. 2 Structures of compounds from Table 2: (a) linalool, (b) geraniol,
(c) nerol, (d) IBMP, (e) cis-Rose oxide, (f) Wine lactone, (g) oaminoaceto-
phenone, (h) 4-methyl-4-mercaptopentan-2-one, (i) 4-methyl-4-
mercaptopentan-2-one, (j) 3-mercapto-1-hexanol, (k) rotundone.
Table 2 Impact odorants contributing to varietal aromas of selected wines
Varietya Characteristic odorants Odor quality Sensory threshold Ref.
Muscat Linalool, Floral 170 ng L!1 (in water) 7,8Terpenols, e.g. geraniol, nerol Citrus, floral
Riesling TDN (1,1,6-trimethyl-1,2-dihydronaphthalene) Kerosene, bottle age 20 mg L!1 9,10Cabernet Sauvignon, Sauvignon blanc,Cabernet franc, Merlot, Carmenere
3-Isobutyl-2-methoxypyrazines (IBMP) Bell pepper 2 ng L!1 (in water) 11–14
Gewurztraminer cis-Rose oxide Geranium oil, carrotleaves
200 ng L!1 15–20
Wine lactone Coconut, woody, sweet 0.02 pg L!1 (in air)Vitis labrusca, Vitis rotundifolia o-Aminoacetophenone Foxy, sweet 400 ng L!1 21,22Sauvignon blanc, Scheurebe 4-Methyl-4-mercaptopentan-2-one Blackcurrant 0.6 ng L!1 in
water–ethanol(90 : 10, w/w)
16,18
Grenache rose, Sauvignon blanc,Semillon
3-Mercapto-1-hexanol Grapefruit/citrus peel(R isomer)
50 ng L!1 23
Passion fruit (S isomer) 60 ng L!1 24Shiraz Rotundone Black pepper 16 ng L!1 (in wine) 25,26a All varieties are Vitis vinifera except where indicated.
2480 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is "c The Royal Society of Chemistry 2008
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Wine flavor: chemistry in a glass
Pavla Polaskova, Julian Herszage and Susan E. Ebeler*
Received 13th May 2008
First published as an Advance Article on the web 12th August 2008
DOI: 10.1039/b714455p
Although hundreds of chemical compounds have been identified in grapes and wines, only a few
compounds actually contribute to sensory perception of wine flavor. This critical review focuses
on volatile compounds that contribute to wine aroma and provides an overview of recent
developments in analytical techniques for volatiles analysis, including methods used to identify the
compounds that make the greatest contributions to the overall aroma. Knowledge of volatile
composition alone is not enough to completely understand the overall wine aroma, however, due
to complex interactions of odorants with each other and with other nonvolatile matrix
components. These interactions and their impact on aroma volatility are the focus of much
current research and are also reviewed here. Finally, the sequencing of the grapevine and yeast
genomes in the past B10 years provides the opportunity for exciting multidisciplinary studies
aimed at understanding the influences of multiple genetic and environmental factors on grape and
wine flavor biochemistry and metabolism (147 references).
Introduction
From Pasteur’s discoveries of the role of microorganisms infermentation and his studies on the analytical separations ofchiral organic acids in grape juice1,2 to Kepler’s developmentof early calculus theories to measure wine barrel volumes,3
grapes and wines have provided a rich basis for many dis-coveries that have had fundamental impacts on mathematics,microbiology, and chemistry over the past several centuries.The chemistry of grape and wine flavor, in particular, has beenthe focus of much research due to the complexity of thevolatile aromas that contribute to flavor and the nuancedvariations that arise from di!erent grape varieties, growingregions, and vintage years. In the 19th and early part of the20th centuries, much of the focus of wine flavor chemistryresearch was on measuring the major components that
contribute to taste and aroma (ethanol, organic acids, sugars),the compounds associated with protecting wine quality,4 andon those compounds associated with ‘‘defects’’ or undesirablearomas such as acetic acid (which results in a vinegar aroma).As fermentation technology improved, the incidence of defectsdecreased, and in the mid-1900s flavor chemists turned theirfocus toward understanding the chemical components thatcontribute to specific sensory attributes associated withdi!erent grapes and wines and di!erent wine styles (e.g., tablewines, port, Sauternes-style wines, etc.). These studies wereenabled by important advances in the development of gaschromatography (GC) in the 1950s and the introduction ofcommercial capillary GC columns in the 1980s. In this reviewwe will first summarize the components that contribute to wineflavor, focusing on aroma components, then we present anoverview of more recent developments in analytical techniquesfor the analysis of wine volatiles, methods for relatingchemical composition to sensory perception of aroma, andthe emerging role of genomics and proteomics for under-standing aroma development in grapes.
Department of Viticulture and Enology, University of California,Davis, One Shields Avenue, Davis, CA 95616, USA.E-mail: [email protected]; Fax: +1 530-752-0382;Tel: +1 530-752-0696
Pavla Polaskova earned her PhD degreein Analytical Chemistry in 2003 from theMasaryk University Brno in the CzechRepublik. Later she worked for two yearsas a postdoctoral scholar in the ChemistryDepartment at the University ofCalifornia Davis. Three years ago shejoined the Viticulture and EnologyDepartment in UC Davis as a post-doctoral scholar, where she is focusingon aroma compounds and flavorinteractions in wine.
In 2001 Julian Herszage earned his PhDdegree in Chemistry from the Universidadde Buenos Aires in Argentina. Followinghis degree he worked for two years as apostdoctoral scholar at the Scripps Insti-tution of Oceanography in San Diego,California. He joined the Viticulture andEnology Department in UC Davis as apostdoctoral scholar in 2006. His researchfocuses on detection and quantification ofvolatile sulfur compounds in wine andunderstanding the factors that influenceformation of these important wine aromacompounds.
Susan Ebeler is a professor in the depart-ment of Viticulture and Enology at UCDavis. Her research is focused on thedevelopment and application of analyticalchemistry techniques to study grape andwine flavor chemistry, understanding thephysico-chemical interactions of flavorswith nonvolatile food and beverage com-ponents, and elucidating the chemicalmechanisms for observed health e!ectsof grape and wine components. She tea-ches undergraduate and graduate classeson Grape and Wine Analysis and FlavorChemistry of Foods and Beverages.
2478 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is !c The Royal Society of Chemistry 2008
CRITICAL REVIEW www.rsc.org/csr | Chemical Society Reviews
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View Article Online / Journal Homepage / Table of Contents for this issue
Chemical components contributing to flavor
Grape and wine flavor is complex and many di!erent sensorymodalities and chemical compounds influence flavor percep-tion (Table 1).5 However, aroma (smell) is the major contri-butor to overall flavor perception and this review will focuslargely on the volatile aroma compounds that contribute togrape and wine flavor.The basic processes for producing red and white wines are
shown in Fig. 1, with the main distinction being that red winesare fermented with the skins present so that more chemicalcomponents from the skins (e.g., anthocyanins, polyphenols,flavor compounds) are extracted into the juice/wine during thefermentation. The complex aromas of the final wine aretherefore derived from the grape, the yeast fermentation(typically Saccharomyces cerevisiae), any secondary microbialfermentations that occur, and the aging/storage conditions.There are clear sensory di!erences in the aromas of most
grape varieties, however the overall volatile composition ofmost varieties is similar, with the varietal aroma derivinglargely from di!erences in relative ratios of many volatilecompounds, as further discussed below. In only a few caseshave individual character impact compounds (see Fig. 2) beenidentified and associated with specific varietal aroma attributes(Table 2) (an impact compound is a single compound thatconveys the named flavor6). Most of the impact compounds
that have been identified are present at low concentrations ingrapes and wines, however because of their very low (ng L!1)sensory thresholds they can have a large impact on the overallgrape/wine aroma.In general, the fermentation-derived volatiles make up the
largest percentage of the total aroma composition of wine.Fermentation by Saccharomyces cerevisiae leads to formationof many alcohols (predominantly ethanol and the C3–C5
straight chain and branched n-alcohols, and 2-phenylethanol)
Fig. 1 White and red wine production. 1Indicates steps that are optional and/or not done on every variety or wine style. 2If skins are removed
from red grape must, a blush or rose juice is obtained; color is dependant on grape varietal and contact time with skins.
Table 1 Sensory modalities and selected chemical components con-tributing to grape and wine flavor
Sensory modality AttributeExample chemicalcompounds in wine
Taste Sweet Glucose, fructose,glycerol, ethanol
Sour Tartaric acidSalty Sodium chloride,
potassium chlorideBitter Catechin
Smell/aroma Floral, lily-of-the valleyaroma
Linalool
Banana-like aroma Isoamyl acetateChemesthesis Mouth-warming/heat EthanolTactile Viscosity Glycerol,
polysaccharidesAstringency Tannins
Vision Red Malvidin-3-glucoside
This journal is "c The Royal Society of Chemistry 2008 Chem. Soc. Rev., 2008, 37, 2478–2489 | 2479
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and esters (predominantly ethyl acetate and isoamyl acetate).The ester 3-methylbutyl acetate appears to be an importantaroma component of many varieties18,27 however, in general,most of the fermentation-derived compounds have relativelyhigh sensory thresholds and therefore do not individuallycontribute significantly to the aroma of wines. Combined,however, their impact may be important as shown in modelsystems.28
In addition to the primary yeast fermentation, some wines(e.g., Chardonnay in the US) undergo a secondary microbialfermentation with Oenococcus oeni (also called malolacticfermentation) and as a result may contain high concentrations
of diacetyl (2,3-butanedione), which contributes a butteryaroma to these wines. The e!ects of fermentation conditionsand reviews of the biochemical processes involved information of the fermentation-derived aromas have beenreviewed by others.29–31
Finally, changes in concentrations of many aromacompounds occur during storage and wine aging. Many winesare stored or fermented in oak barrels and one of the mostimportant volatiles extracted from the wood is b-methyl-g-octalactone (known as oak- or whiskey-lactone) which con-tributes a woody, oaky, coconut-like aroma to the wine. Thiscompound occurs as two isomers, cis- and trans-, and likemany isomeric compounds, the sensory properties are depen-dent on the isomeric structure. As reviewed by Waterhouseand Towey,32 the cis-oak lactone isomer has an aromathreshold reported as 92 mg L!1, compared to 460 mg L!1
for the trans-isomer and the ratio of the two isomers varieswith oak species and origin. Interestingly, several studies haveshown that the wood can also adsorb some aroma compounds(2-phenylethanol, ethyl decanoate)33–35 changing their concen-tration in solution. These adsorption reactions appear to be afunction of the ratio of wood surface area/solution volumeand are driven by acid–base and polar characteristics of thewood rather than solubility and hydrophobicity of the studiedaroma compounds.33 Wines can also be fermented and aged instainless steel tanks leading to wines that have simpler sensoryproperties mostly due to the lack of the compounds found inwine aged in oak barrels such as lactones and some phenoliccompounds.36,37
In addition to extraction of flavor compounds from oak,chemical and microbial (e.g., Acetobacter) oxidative reactionscan make significant contributions to the flavor of aged winesas a result of formation of compounds such as acetaldehyde(nutty, sherry-like aroma) and acetic acid (vinegar aroma).While acetaldehyde can contribute desirable characteristicaromas to aged wines and Sherries, if oxidative reactions areuncontrolled they can lead to very high concentrations ofacetaldehyde and acetic acid and the overall sensory impactis undesirable.
Fig. 2 Structures of compounds from Table 2: (a) linalool, (b) geraniol,
(c) nerol, (d) IBMP, (e) cis-Rose oxide, (f) Wine lactone, (g) oaminoaceto-
phenone, (h) 4-methyl-4-mercaptopentan-2-one, (i) 4-methyl-4-
mercaptopentan-2-one, (j) 3-mercapto-1-hexanol, (k) rotundone.
Table 2 Impact odorants contributing to varietal aromas of selected wines
Varietya Characteristic odorants Odor quality Sensory threshold Ref.
Muscat Linalool, Floral 170 ng L!1 (in water) 7,8Terpenols, e.g. geraniol, nerol Citrus, floral
Riesling TDN (1,1,6-trimethyl-1,2-dihydronaphthalene) Kerosene, bottle age 20 mg L!1 9,10Cabernet Sauvignon, Sauvignon blanc,Cabernet franc, Merlot, Carmenere
3-Isobutyl-2-methoxypyrazines (IBMP) Bell pepper 2 ng L!1 (in water) 11–14
Gewurztraminer cis-Rose oxide Geranium oil, carrotleaves
200 ng L!1 15–20
Wine lactone Coconut, woody, sweet 0.02 pg L!1 (in air)Vitis labrusca, Vitis rotundifolia o-Aminoacetophenone Foxy, sweet 400 ng L!1 21,22Sauvignon blanc, Scheurebe 4-Methyl-4-mercaptopentan-2-one Blackcurrant 0.6 ng L!1 in
water–ethanol(90 : 10, w/w)
16,18
Grenache rose, Sauvignon blanc,Semillon
3-Mercapto-1-hexanol Grapefruit/citrus peel(R isomer)
50 ng L!1 23
Passion fruit (S isomer) 60 ng L!1 24Shiraz Rotundone Black pepper 16 ng L!1 (in wine) 25,26a All varieties are Vitis vinifera except where indicated.
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and esters (predominantly ethyl acetate and isoamyl acetate).The ester 3-methylbutyl acetate appears to be an importantaroma component of many varieties18,27 however, in general,most of the fermentation-derived compounds have relativelyhigh sensory thresholds and therefore do not individuallycontribute significantly to the aroma of wines. Combined,however, their impact may be important as shown in modelsystems.28
In addition to the primary yeast fermentation, some wines(e.g., Chardonnay in the US) undergo a secondary microbialfermentation with Oenococcus oeni (also called malolacticfermentation) and as a result may contain high concentrations
of diacetyl (2,3-butanedione), which contributes a butteryaroma to these wines. The e!ects of fermentation conditionsand reviews of the biochemical processes involved information of the fermentation-derived aromas have beenreviewed by others.29–31
Finally, changes in concentrations of many aromacompounds occur during storage and wine aging. Many winesare stored or fermented in oak barrels and one of the mostimportant volatiles extracted from the wood is b-methyl-g-octalactone (known as oak- or whiskey-lactone) which con-tributes a woody, oaky, coconut-like aroma to the wine. Thiscompound occurs as two isomers, cis- and trans-, and likemany isomeric compounds, the sensory properties are depen-dent on the isomeric structure. As reviewed by Waterhouseand Towey,32 the cis-oak lactone isomer has an aromathreshold reported as 92 mg L!1, compared to 460 mg L!1
for the trans-isomer and the ratio of the two isomers varieswith oak species and origin. Interestingly, several studies haveshown that the wood can also adsorb some aroma compounds(2-phenylethanol, ethyl decanoate)33–35 changing their concen-tration in solution. These adsorption reactions appear to be afunction of the ratio of wood surface area/solution volumeand are driven by acid–base and polar characteristics of thewood rather than solubility and hydrophobicity of the studiedaroma compounds.33 Wines can also be fermented and aged instainless steel tanks leading to wines that have simpler sensoryproperties mostly due to the lack of the compounds found inwine aged in oak barrels such as lactones and some phenoliccompounds.36,37
In addition to extraction of flavor compounds from oak,chemical and microbial (e.g., Acetobacter) oxidative reactionscan make significant contributions to the flavor of aged winesas a result of formation of compounds such as acetaldehyde(nutty, sherry-like aroma) and acetic acid (vinegar aroma).While acetaldehyde can contribute desirable characteristicaromas to aged wines and Sherries, if oxidative reactions areuncontrolled they can lead to very high concentrations ofacetaldehyde and acetic acid and the overall sensory impactis undesirable.
Fig. 2 Structures of compounds from Table 2: (a) linalool, (b) geraniol,
(c) nerol, (d) IBMP, (e) cis-Rose oxide, (f) Wine lactone, (g) oaminoaceto-
phenone, (h) 4-methyl-4-mercaptopentan-2-one, (i) 4-methyl-4-
mercaptopentan-2-one, (j) 3-mercapto-1-hexanol, (k) rotundone.
Table 2 Impact odorants contributing to varietal aromas of selected wines
Varietya Characteristic odorants Odor quality Sensory threshold Ref.
Muscat Linalool, Floral 170 ng L!1 (in water) 7,8Terpenols, e.g. geraniol, nerol Citrus, floral
Riesling TDN (1,1,6-trimethyl-1,2-dihydronaphthalene) Kerosene, bottle age 20 mg L!1 9,10Cabernet Sauvignon, Sauvignon blanc,Cabernet franc, Merlot, Carmenere
3-Isobutyl-2-methoxypyrazines (IBMP) Bell pepper 2 ng L!1 (in water) 11–14
Gewurztraminer cis-Rose oxide Geranium oil, carrotleaves
200 ng L!1 15–20
Wine lactone Coconut, woody, sweet 0.02 pg L!1 (in air)Vitis labrusca, Vitis rotundifolia o-Aminoacetophenone Foxy, sweet 400 ng L!1 21,22Sauvignon blanc, Scheurebe 4-Methyl-4-mercaptopentan-2-one Blackcurrant 0.6 ng L!1 in
water–ethanol(90 : 10, w/w)
16,18
Grenache rose, Sauvignon blanc,Semillon
3-Mercapto-1-hexanol Grapefruit/citrus peel(R isomer)
50 ng L!1 23
Passion fruit (S isomer) 60 ng L!1 24Shiraz Rotundone Black pepper 16 ng L!1 (in wine) 25,26a All varieties are Vitis vinifera except where indicated.
2480 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is "c The Royal Society of Chemistry 2008
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and esters (predominantly ethyl acetate and isoamyl acetate).The ester 3-methylbutyl acetate appears to be an importantaroma component of many varieties18,27 however, in general,most of the fermentation-derived compounds have relativelyhigh sensory thresholds and therefore do not individuallycontribute significantly to the aroma of wines. Combined,however, their impact may be important as shown in modelsystems.28
In addition to the primary yeast fermentation, some wines(e.g., Chardonnay in the US) undergo a secondary microbialfermentation with Oenococcus oeni (also called malolacticfermentation) and as a result may contain high concentrations
of diacetyl (2,3-butanedione), which contributes a butteryaroma to these wines. The e!ects of fermentation conditionsand reviews of the biochemical processes involved information of the fermentation-derived aromas have beenreviewed by others.29–31
Finally, changes in concentrations of many aromacompounds occur during storage and wine aging. Many winesare stored or fermented in oak barrels and one of the mostimportant volatiles extracted from the wood is b-methyl-g-octalactone (known as oak- or whiskey-lactone) which con-tributes a woody, oaky, coconut-like aroma to the wine. Thiscompound occurs as two isomers, cis- and trans-, and likemany isomeric compounds, the sensory properties are depen-dent on the isomeric structure. As reviewed by Waterhouseand Towey,32 the cis-oak lactone isomer has an aromathreshold reported as 92 mg L!1, compared to 460 mg L!1
for the trans-isomer and the ratio of the two isomers varieswith oak species and origin. Interestingly, several studies haveshown that the wood can also adsorb some aroma compounds(2-phenylethanol, ethyl decanoate)33–35 changing their concen-tration in solution. These adsorption reactions appear to be afunction of the ratio of wood surface area/solution volumeand are driven by acid–base and polar characteristics of thewood rather than solubility and hydrophobicity of the studiedaroma compounds.33 Wines can also be fermented and aged instainless steel tanks leading to wines that have simpler sensoryproperties mostly due to the lack of the compounds found inwine aged in oak barrels such as lactones and some phenoliccompounds.36,37
In addition to extraction of flavor compounds from oak,chemical and microbial (e.g., Acetobacter) oxidative reactionscan make significant contributions to the flavor of aged winesas a result of formation of compounds such as acetaldehyde(nutty, sherry-like aroma) and acetic acid (vinegar aroma).While acetaldehyde can contribute desirable characteristicaromas to aged wines and Sherries, if oxidative reactions areuncontrolled they can lead to very high concentrations ofacetaldehyde and acetic acid and the overall sensory impactis undesirable.
Fig. 2 Structures of compounds from Table 2: (a) linalool, (b) geraniol,
(c) nerol, (d) IBMP, (e) cis-Rose oxide, (f) Wine lactone, (g) oaminoaceto-
phenone, (h) 4-methyl-4-mercaptopentan-2-one, (i) 4-methyl-4-
mercaptopentan-2-one, (j) 3-mercapto-1-hexanol, (k) rotundone.
Table 2 Impact odorants contributing to varietal aromas of selected wines
Varietya Characteristic odorants Odor quality Sensory threshold Ref.
Muscat Linalool, Floral 170 ng L!1 (in water) 7,8Terpenols, e.g. geraniol, nerol Citrus, floral
Riesling TDN (1,1,6-trimethyl-1,2-dihydronaphthalene) Kerosene, bottle age 20 mg L!1 9,10Cabernet Sauvignon, Sauvignon blanc,Cabernet franc, Merlot, Carmenere
3-Isobutyl-2-methoxypyrazines (IBMP) Bell pepper 2 ng L!1 (in water) 11–14
Gewurztraminer cis-Rose oxide Geranium oil, carrotleaves
200 ng L!1 15–20
Wine lactone Coconut, woody, sweet 0.02 pg L!1 (in air)Vitis labrusca, Vitis rotundifolia o-Aminoacetophenone Foxy, sweet 400 ng L!1 21,22Sauvignon blanc, Scheurebe 4-Methyl-4-mercaptopentan-2-one Blackcurrant 0.6 ng L!1 in
water–ethanol(90 : 10, w/w)
16,18
Grenache rose, Sauvignon blanc,Semillon
3-Mercapto-1-hexanol Grapefruit/citrus peel(R isomer)
50 ng L!1 23
Passion fruit (S isomer) 60 ng L!1 24Shiraz Rotundone Black pepper 16 ng L!1 (in wine) 25,26a All varieties are Vitis vinifera except where indicated.
2480 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is "c The Royal Society of Chemistry 2008
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Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali
on a point interval scale as it elutes from the GC column. Anadvantage of the TI methods relative to other GC-O methodsis that more sni!ers/assessors can evaluate the same sample ina given time span since intensity is measured during a singleGC run while the dilution methods require multiple analysesof the same sample over several dilutions to calculate thearoma dilution or Charms values. In addition, the intensityratings from multiples assessors can be statistically evaluatedusing TI methods.Another final variation, the Detection Frequency Method,
is based on the frequency of odorant detection by a panel of8–12 persons who separately sni! the GC eluent of thenondiluted extract. The individual aromagrams are recordedand the odor’s intensity is estimated based on the number ofpanelists who detect the odor (detection frequency).87–89
Limitations to the GC-O methods have been reviewed.90
Most importantly, the GC-O techniques are based onseparation of mixtures into individual components, whilehuman sensory perception of the overall aroma of a wine orother food sample is integrative and takes into account thecombined sensations of all components, including any additiveor masking e!ects that may occur when the aroma of complexmixtures is smelled. In addition, odor quality of some
compounds can change with changing concentration so thatperceptual di!erences may occur as peaks elute from the GCcolumn and as odorant concentrations in solution change. Ifpeaks are poorly resolved, odor perception may be dependenton relative concentrations of the unresolved odorants as theyelute. Finally significant di!erences in individual sensitivitiesto odorants occur, requiring careful training and standardiza-tion of GC-O protocols.91–93 However, GC-O remains apowerful tool for identifying important odorants that contri-bute to grape and wine aroma and for relating the contribu-tions of individual odorants to the di!erences among di!erentwines samples (Table 3).
Reconstitution and omission tests
As discussed previously, one of the principal drawbacks ofGC-O approaches for identifying important odorants, is thatthey consider only the impact of isolated aroma compoundsand they overlook the additive (or masking) e!ects of aromacompounds in a mixture. Therefore, once a set of potentiallyimportant odorants are identified by GC-O, additional recon-stitution tests are often performed by mixing together theseodorants at the concentrations at which they are present in the
Table 3 Important odorants in several varietal wines identified using GC-O techniques as reported in selected literature sources
Variety Most important odorants identified by Various GC-O methods Ref.
Scheurebe 4-Mercapto-4-methylpentan-2-one, ethyl 2-methylbutyrate, 3-methylbutanol,2-phenylethanol, 3-ethylphenol, 3-hydroxy-4,5-dimethyl-2(5H)-furanoneand wine lactone
16
Gewurztraminer cis-Rose oxide, ethyl 2-methylbutyrate, 3-methylbutanol, 2-phenylethanol,3-ethylphenol, 3-hydroxy-4,5-dimethyl-2(5H)-furanone and wine lactone
16
Grenache rose 3-Mercapto-1-hexanol, furaneol, homofuraneol 23Chardonnay Ethyl butanoate, octanoic acid, 2-phenylacetaldehyde, 4-vinyphenol,
d-decalactone, 2-methyltetrahydrothiophen-3-one, 3-methylbutyl acetate,decanoic acid, 4-vinyl-2-methoxyphenol and linalool
94,95
Spanish Rioja (blend of Tempranillo,Grenache and Graciano grape varieties)
4-Ethylguaiacol, (E)-whiskey lactone, 4-ethylphenol, b-damascenone,fusel alcohols, isovaleric and hexanoic acids, eugenol, fatty acid ethyl esters,ethyl esters of isoacids, furaneol, 2-phenylacetic acid and (E)-2-hexenal
96
Zalema Mainly fatty acids and their ethyl esters, b-damascenone andb-ionone, isoamyl alcohol and 2-phenylethanol, 4-mercapto-4-methyl-2-pentanone,3-mercaptohexyl acetate, 3-mercapto-1-hexanol, acetaldehyde and 2-phenylacetaldehyde
97
Castanal b-Ionone, 3-methyl-1-butanol, benzyl alcohol, 2-phenylethanol,ethyl acetate, isoamyl acetate, ethyl lactate, ethyl butyrate, ethyl hexanoateand ethyl octanoate
98
Pinot Noir 2-Phenylethanol, 3-methyl-1-butanol, 2-methylpropanoate,ethyl butanoate, 3-methylbutyl acetate, ethyl hexanoate, benzaldehyde,
70
Cabernet Sauvignon and Merlotfrom Bordeaux
Methylbutanols, 2-phenylethanol, 2-methyl-3-sulfanylfuran,acetic acid, 3-(methylsulfanyl)propanal, methylbutanoic acids,b-damascenone, 3-sulfanylhexan-1-ol, furaneol, homofuraneol
99
Cabernet Sauvignon and Merlotfrom USA and Australia
3-Methyl-1-butanol, 3-hydroxy-2-butanone, octanal, ethyl hexanoate,ethyl 2-methylbutanoate, b-damascenone, 2-methoxyphenol,4-ethenyl-2-methoxyphenol, ethyl 3-methylbutanoate, acetic acid and 2-phenylethanol
100
Madeira (Malvazia, Boal, Verdelhoand Sercial varieties)
Sotolon, 2-phenylacetaldehyde, (Z)-whiskey lactone 101
Riesling (from Croatia) 2-Phenylethanol, 3-methyl-1-butanol, 3-(methylthio)-1-propanol,ethyl propanoate, ethyl butanoate, ethyl 3-methylbutanoate, 3-methyl-1-butanol acetate,ethyl hexanoate, ethyl octanoate, ethyl 3-hydroxybutanoate, 2-phenylethyl acetate,hexanoic acid, 3-methylbutanoic acid, butanoic acid, b-damascenone,g-undecalactone and 4-vinylguaiacol
102
Riesling (from US) b-Damascenone, 2-phenylethanol, linalool, fatty acids,ethyl 2-methyl butyrate, trans-2-hexenol, cis-3-hexenol, geraniol, ethyl butyrate, carvone,ethyl hexanoate, isoamyl acetate
103
Seyval blanc o-Aminoacetophenone, b-damascenone, C4 fatty acids,linalool, 1-octen-3-ol, vanillin
103
Vidal blanc b-Damascenone, 2-phenylethanol, methyl anthranilate, vanillin 103Cayuga White b-Damascenone, vanillin, 2-phenylethanol, geraniol, hexanal 103
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Wine flavor: chemistry in a glass
Pavla Polaskova, Julian Herszage and Susan E. Ebeler*
Received 13th May 2008
First published as an Advance Article on the web 12th August 2008
DOI: 10.1039/b714455p
Although hundreds of chemical compounds have been identified in grapes and wines, only a few
compounds actually contribute to sensory perception of wine flavor. This critical review focuses
on volatile compounds that contribute to wine aroma and provides an overview of recent
developments in analytical techniques for volatiles analysis, including methods used to identify the
compounds that make the greatest contributions to the overall aroma. Knowledge of volatile
composition alone is not enough to completely understand the overall wine aroma, however, due
to complex interactions of odorants with each other and with other nonvolatile matrix
components. These interactions and their impact on aroma volatility are the focus of much
current research and are also reviewed here. Finally, the sequencing of the grapevine and yeast
genomes in the past B10 years provides the opportunity for exciting multidisciplinary studies
aimed at understanding the influences of multiple genetic and environmental factors on grape and
wine flavor biochemistry and metabolism (147 references).
Introduction
From Pasteur’s discoveries of the role of microorganisms infermentation and his studies on the analytical separations ofchiral organic acids in grape juice1,2 to Kepler’s developmentof early calculus theories to measure wine barrel volumes,3
grapes and wines have provided a rich basis for many dis-coveries that have had fundamental impacts on mathematics,microbiology, and chemistry over the past several centuries.The chemistry of grape and wine flavor, in particular, has beenthe focus of much research due to the complexity of thevolatile aromas that contribute to flavor and the nuancedvariations that arise from di!erent grape varieties, growingregions, and vintage years. In the 19th and early part of the20th centuries, much of the focus of wine flavor chemistryresearch was on measuring the major components that
contribute to taste and aroma (ethanol, organic acids, sugars),the compounds associated with protecting wine quality,4 andon those compounds associated with ‘‘defects’’ or undesirablearomas such as acetic acid (which results in a vinegar aroma).As fermentation technology improved, the incidence of defectsdecreased, and in the mid-1900s flavor chemists turned theirfocus toward understanding the chemical components thatcontribute to specific sensory attributes associated withdi!erent grapes and wines and di!erent wine styles (e.g., tablewines, port, Sauternes-style wines, etc.). These studies wereenabled by important advances in the development of gaschromatography (GC) in the 1950s and the introduction ofcommercial capillary GC columns in the 1980s. In this reviewwe will first summarize the components that contribute to wineflavor, focusing on aroma components, then we present anoverview of more recent developments in analytical techniquesfor the analysis of wine volatiles, methods for relatingchemical composition to sensory perception of aroma, andthe emerging role of genomics and proteomics for under-standing aroma development in grapes.
Department of Viticulture and Enology, University of California,Davis, One Shields Avenue, Davis, CA 95616, USA.E-mail: [email protected]; Fax: +1 530-752-0382;Tel: +1 530-752-0696
Pavla Polaskova earned her PhD degreein Analytical Chemistry in 2003 from theMasaryk University Brno in the CzechRepublik. Later she worked for two yearsas a postdoctoral scholar in the ChemistryDepartment at the University ofCalifornia Davis. Three years ago shejoined the Viticulture and EnologyDepartment in UC Davis as a post-doctoral scholar, where she is focusingon aroma compounds and flavorinteractions in wine.
In 2001 Julian Herszage earned his PhDdegree in Chemistry from the Universidadde Buenos Aires in Argentina. Followinghis degree he worked for two years as apostdoctoral scholar at the Scripps Insti-tution of Oceanography in San Diego,California. He joined the Viticulture andEnology Department in UC Davis as apostdoctoral scholar in 2006. His researchfocuses on detection and quantification ofvolatile sulfur compounds in wine andunderstanding the factors that influenceformation of these important wine aromacompounds.
Susan Ebeler is a professor in the depart-ment of Viticulture and Enology at UCDavis. Her research is focused on thedevelopment and application of analyticalchemistry techniques to study grape andwine flavor chemistry, understanding thephysico-chemical interactions of flavorswith nonvolatile food and beverage com-ponents, and elucidating the chemicalmechanisms for observed health e!ectsof grape and wine components. She tea-ches undergraduate and graduate classeson Grape and Wine Analysis and FlavorChemistry of Foods and Beverages.
2478 | Chem. Soc. Rev., 2008, 37, 2478–2489 This journal is !c The Royal Society of Chemistry 2008
CRITICAL REVIEW www.rsc.org/csr | Chemical Society Reviews
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Chemical components contributing to flavor
Grape and wine flavor is complex and many di!erent sensorymodalities and chemical compounds influence flavor percep-tion (Table 1).5 However, aroma (smell) is the major contri-butor to overall flavor perception and this review will focuslargely on the volatile aroma compounds that contribute togrape and wine flavor.The basic processes for producing red and white wines are
shown in Fig. 1, with the main distinction being that red winesare fermented with the skins present so that more chemicalcomponents from the skins (e.g., anthocyanins, polyphenols,flavor compounds) are extracted into the juice/wine during thefermentation. The complex aromas of the final wine aretherefore derived from the grape, the yeast fermentation(typically Saccharomyces cerevisiae), any secondary microbialfermentations that occur, and the aging/storage conditions.There are clear sensory di!erences in the aromas of most
grape varieties, however the overall volatile composition ofmost varieties is similar, with the varietal aroma derivinglargely from di!erences in relative ratios of many volatilecompounds, as further discussed below. In only a few caseshave individual character impact compounds (see Fig. 2) beenidentified and associated with specific varietal aroma attributes(Table 2) (an impact compound is a single compound thatconveys the named flavor6). Most of the impact compounds
that have been identified are present at low concentrations ingrapes and wines, however because of their very low (ng L!1)sensory thresholds they can have a large impact on the overallgrape/wine aroma.In general, the fermentation-derived volatiles make up the
largest percentage of the total aroma composition of wine.Fermentation by Saccharomyces cerevisiae leads to formationof many alcohols (predominantly ethanol and the C3–C5
straight chain and branched n-alcohols, and 2-phenylethanol)
Fig. 1 White and red wine production. 1Indicates steps that are optional and/or not done on every variety or wine style. 2If skins are removed
from red grape must, a blush or rose juice is obtained; color is dependant on grape varietal and contact time with skins.
Table 1 Sensory modalities and selected chemical components con-tributing to grape and wine flavor
Sensory modality AttributeExample chemicalcompounds in wine
Taste Sweet Glucose, fructose,glycerol, ethanol
Sour Tartaric acidSalty Sodium chloride,
potassium chlorideBitter Catechin
Smell/aroma Floral, lily-of-the valleyaroma
Linalool
Banana-like aroma Isoamyl acetateChemesthesis Mouth-warming/heat EthanolTactile Viscosity Glycerol,
polysaccharidesAstringency Tannins
Vision Red Malvidin-3-glucoside
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Profumi, sapori e colori: aspetti chimici e sensoriali
INTRODUCTION 227
TABLE 7.1. The GC / MS Qualitative and Semiquantitative Data of Volatile Compounds Identifi ed in 50% Hydroalcohol Extract of Different Types of Wood Used in Making Barrels for Wine and Spirits Aging a
Compound Acacia Chestnut Cherry Mulberry Oak
Aldehydes and Ketones
Furfural * * * Benzaldehyde * * Methylbenzaldehyde * Hydroxybenzaldehyde * * Anisaldehyde * Cinnamaldehyde * Vanillin * * * * * * * * * * Syringaldehyde * * * * * * * * * * * Coniferaldehyde * * * * * * * Acetophenone * * * * * * * Benzophenone * * Acetovanillone * * * * 3 - Methoxyacetovanillone * * 2 - Butanone - 4 - guaiacol * * 2,4 - Dihydroxybenzaldeide * * * * * 3 - Buten - 2 - one - 4 - phenyl * *
Alcohols and Phenols
! - Terpineol * * * * * * 3 - Oxo - ! - ionol * * * * * * " - Phenylethanol * * * * * Benzenepropanol * ! - Methylbenzenepropanol * * Coniferyl alcohol * Benzotriazole * * * * * * * 4 - Methylphenol * 4 - Ethylphenol * 4 - Methylguaiacol * Ethylguaiacol * Vinylguaiacol * tr * Eugenol * * * tr tr * * * Methoxyeugenol * * * * * * * 3 - Methoxyphenol * Dimethoxyphenol * * Trimethoxyphenol * * * * * * * 1,2,3 - Trimethoxybenzene * *
and furan compounds (Puech et al., 1999 ; P é rez - Coello et al., 1999 ; Guichard et al., 1995 ; Feuillat et al., 1997 ; Masson et al., 1996 ; 2000 ; Matricardi and Waterhouse, 1999 ; Hale et al., 1999 ; Sauvageot and Feuillat, 1999 ; Ibern - G ó mez et al., 2001 ; Chatonnet et al., 1992 ). Main compounds characterized by sensorial proprieties are vanillin (45)
228 COMPOUNDS RELEASED IN WINE FROM WOOD
Compound Acacia Chestnut Cherry Mulberry Oak
Acids and Esters
Ethyl benzoate * 2,5 - Dihydroxy ethyl benzoate * * Methyl salicylate * trans - ! - Methyl - " - octalactone * * * cis - ! - Methyl - " - octalactone * * * Homovanillic acid * * * * * Capronic acid * * * * * * * * Caprylic acid * * * * * * Lauric acid * * * * * * * Myristic acid * * * * * * * * * Pentadecanoic acid * * * * * * * * Palmitic acid * * * * * * * * * * * * * * Margaric acid * * * * * * * Stearic acid * * * * * * * * * * Oleic acid * * * * * * * * Linoleic acid * * * * * * * * * * Linolenic acid * * *
a (Not subjected to any toasting treatment). Data expressed as µ g/g of 1 - heptanol (internal standard). * 0.1 – 0.9 µ g/g wood; * * 1 – 10 µ g/g wood; * * * > 10 µ g/g wood; tr, trace (De Rosso et al., 2008 ).
TABLE 7.1. (Continued)
(vanilla note; sensory threshold 0.3 ppm) and eugenol (35) (clove, spicy; sensory threshold 0.5 ppm; Boidron et al., 1988 ). Toasting of wood made for making barrels induces formation of a great number of vola-tile and odoriferous compounds. In general, furan and pyran deriva-tives formed with heating wood are characterized from a toasty caramel aroma (Cutzach et al., 1997 ; Chatonnet, 1999 ). Among the compounds formed with toasting were ( 1 ) 3,5 - dihydroxy - 2 - methyl - 4 H - pyran - 4 - one, ( 2 ) 3 - hydroxy - 2 - methyl - 4 H - pyran - 4 - one or maltol, ( 3 ) 2,3 - dihydro - 3,5 - dihydroxy - 6 - methyl - 4 H - pyran - 4 - one (DDMP), ( 4 ) 4 - hydroxy - 2,5 - dimethylfuran - 3(2 H ) - one (furaneol), ( 5 ) 2,3 - dihydro - 5 - hydroxy - 6 - methyl - 4 H - pyran - 4 - one (dihydromaltol), ( 6 ) 2 - hydroxy - 3 - methyl - 2 - cyclopenten - 1 - one (or cyclotene) and 5 - (acetoxymethyl)furfural. The structures of com-pounds 1 – 6 are shown in Fig. 7.1 . Formation of these molecules in the presence of proline infers that Maillard reactions occur. The GC/MS – EI (70 eV) mass spectra of some of them are reported in the Table 7.2 . A complete list of compounds identifi ed in toasted oak wood extracts is reported in Table 7.3 .
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
INTRODUCTION 229
Figure 7.1. Structures of volatile compounds characterized from “ toasty caramel ” aroma released in wine from toasted woods during aging. ( 1 ) 3,5 - dihydroxy - 2 - methyl - 4 H - pyran - 4 - one; ( 2 ) 3 - hydroxy - 2 - methyl - 4 H - pyran - 4 - one; ( 3 ) 2,3 - dihydro - 3,5 - dihydroxy - 6 - methyl - 4 H - pyran - 4 - one (DDMP); ( 4 ) 4 - hydroxy - 2,5 - dimethylfuran - 3(2 H ) - one (furaneol); ( 5 ) 2,3 - dihydro - 5 - hydroxy - 6 - methyl - 4 H - pyran - 4 - one (dihydro-maltol); ( 6 ) 2 - hydroxy - 3 - methyl - 2 - cyclopenten - 1 - one (or cycloteme) (Cutzach et al., 1997 ).
CH3
CH3CH3
O
O
1 2 3
4 5 6
O
O
OHHO
HO
CH3O
O
OHHO
CH3 CH3
O
O O
OHOH
CH3O
O
OH
TABLE 7.2. Principal Fragments Observed in the GC / MS – EI (70 eV) Mass Spectra of Compounds in Fig. 7.1 With Their Relative Abundance a
Compound ( m/z )
3,5 - Dihydroxy - 2 - methyl - 4 H - pyran - 4 - one ( 1 ) 142(100), 55(37), 68(30), 43(29), 85(18), 96(11)
2,3 - Dihydro - 3,5 - dihydroxy - 6 - methyl - 4 H - pyran - 4 - one ( 3 ) 43(100), 144(36), 101(32), 73(21), 55(18)
4 - Hydroxy - 2,5 - dimethylfuran - 3(2 H ) - one ( 4 ) 43(100), 128(71), 57(64), 85(21), 55(21)
2,3 - Dihydro - 5 - hydroxy - 6 - methyl - 4 H - pyran - 4 - one ( 5 ) 43(100), 128(76), 72(26), 57(24), 85(8)
a Cutzach et al., 1997 .
Some compounds from wood may induce defects to the wine. Carbonyl compounds, such as ( E ) - 2 - nonenal, ( E ) - 2 - octenal, 3 - octen - 1 - one, and 1 - decanal are responsible for the sawdust smell sometimes found in the wine after ageing in new 225 - L oak wood barrels (bar-riques); ( E ) - 2 - nonenal is reputed as being mainly responsible for the sawdust smell of wine (Chatonnet and Dubourdieu, 1998 ).
Gianluca Gilardoni Riccagioia, 16 ottobre 2013
Profumi, sapori e colori: aspetti chimici e sensoriali 124 VOLATILE AND AROMA COMPOUNDS IN WINES
Figure 5.2. Volatile sulfur compounds of wines: ( 15 ) dimethyl sulfi de, ( 16 ) ethylmer-captan, ( 17 ) diethyl sulfi de, ( 18 ) methyl thioacetate, ( 19 ) dimethyl disulfi de, ( 20 ) ethyl thioacetate, ( 21 ) diethyl disulfi de, ( 22 ) 2 - mercaptoethanol, ( 23 ) 2 - (methylthio) - 1 - ethanol, ( 24 ) 3 - (methylthio) - 1 - propanol, ( 25 ) 4 - (methylthio) - 1 - butanol, ( 26 ) 3 - mercap-tohexan - 1 - ol, ( 27 ) 4 - methyl - 4 - mercaptopentan - 2 - one, ( 28 ) 3 - mercaptohexanol acetate, ( 29 ) benzothiazole, ( 30 ) 5 - (2 - hydroxyethyl) - 4 - methylthiazole, ( 31 ) trans - 2 - methylthio-phan - 3 - ol, ( 32 ) 2 - methyltetrahydrothiophen - 3 - one.
S HS S S
O
SS
S
O
SS
OHHS S
OH
SOH
S OH
OHS
O
O SH
HO
SH
N
S
N
SOH
S
OH
CH3
SO
15 16 17 18
20 21 22 23
19
262524
292827
323130
addition of 5 - g Na 2 SO 4 to 50 mL of the sample, extraction was per-formed with 2 ! 5 mL of ethyl acetate. The GC/MS – EI (70 eV) mass spectrum of bis(2 - hydroxyethyl)disulfi de is reported in Fig. 5.3 .
5.2.2 HS – SPME – GC / MS Analysis of Volatile Sulfur Compounds
The carboxen – polydimethylsiloxane – divinylbenzene (CAR/PDMS/DVB) 50 : 30 µ m and 2 - cm length resulted in the more effi cient fi ber for the extraction of sulfur compounds with the simple sampling condi-tions (e.g., ionic strength, sample temperature, and adsorption time) (Fedrizzi et al., 2007a ). A suitable HS – solution volumes ratio is 1 : 2 (Mestres et al., 2000 ). Figure 5.4 reports the HS – SPME – GC/MS chro-matograms relative to analyses of compounds used as internal stan-dards (a) and of analytes (b) using the SPME conditions reported
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
MASS SPECTROMETRY IN GRAPE AND WINE CHEMISTRY
RICCARDO FLAMINICRA, Centro di Ricerca per la Viticoltura, Conegliano (TV), Italy
PIETRO TRALDICNR, Istituto di Scienze e Tecnologie Molecolari, Padova, Italy
A JOHN WILEY & SONS, INC., PUBLICATION
THE SPME–GC/MS/MS ANALYSIS OF TCA AND TBA IN WINE 253
8.2.2 The GC / MS Analysis
Chloroanisoles (2,4 - dichloroanisole, TCA, 2,3,4,6 - tetrachloroanisole, pentachloroanisole, TCP, 2,3,4,6 - tetrachlorophenol, pentachlorophe-nol) in wines or cork stopper extracts are usually analyzed using a 5% diphenyl – 95% dimethyl polysiloxane GC column (e.g., 30 m ! 0.25 mm i.d., 0.25 - µ m fi lm thickness). By using a singular quadrupole mass spec-trometer recording signals in SIM mode, TCA is quantifi ed on the sum of signals m/z 195+197+199+210+212+214, with the last two coming from molecules containing one or two 37 Cl atoms, respectively.
The signals recorded for analysis of TCP are at m/z 196, 198 and 200, for tetrachlorophenol at m/z 229, 231, 244 and 246. By performing SPME - GC/MS - SIM single quadrupole analysis the LOD and LOQ achieved for TCA are 0.2 and 0.4 ng/L, respectively (Lizarraga et al., 2004 ). The GC/MS – electron impact (EI 70 eV) fragmentation spectra of TCA is reported in Fig. 8.7 .
A GC/MS – EI chromatogram recorded in the analysis of TCA and TCP in wine is shown in Fig. 8.8 ; below the chromatographic conditions used are reported.
The TCA can be determined using an ion trap system performing collision - induced dissociation (CID). Quantifi cation is based on the daughter ion signals of the M + • species at m/z 210 and 212 used as precur-sor ions. Depending on the system used, CID can be performed in either resonant or non - resonant mode. In the former condition, the most intense daughter ions are at m/z 195 and 197, in non - resonant mode the principal signals are at m/z 167 and 169. The CID of a wine spiked with
Figure 8.7. The GC/MS – EI fragmentation spectrum (70 eV) of 2,4,6 - trichloroanisole.
230m/z
Rel
ativ
e ab
unda
nce
2202102001901801701601501401301201101009080706050403020
OCl Cl
Cl
H3C100
50
2936
49
62 74
83
97
109
132 145160
167
181
195
210
0
258 COMPOUNDS RESPONSIBLE FOR WINE DEFECTS
Figure 8.11. The GC/MS – EI (70 eV) mass spectrum of geosmin [octahydro - 4,8 a - dimethyl - 4 a (2 H ) - naphthalenol, C 12 H 22 O, MW 82.30248]. (Reproduced from Journal of Agricultural and Food Chemistry , 2000, 48 p. 4837, Darriet et al., with permission of American Chemical Society.)
50 75 100 125 150 175 m/z
Relativeintensity
100%
4155
67 8397
125
135 149 167 182
112
HO
at m/z 58 (Darriet et al., 2000 ). Performing MS/MS analysis of the signal at m/z 112 quantifi cation of geosmin is done on the daughter ion at m/z 97. The SPME – GC/MS analysis using geosmine - d 5 as internal standard gave a LOD of 5 ng/L (Dumoulin et al., 2004 ).
8.4 ANALYSIS OF 1 - OCTEN - 3 - ONE
1 - Octen - 3 - one is a compound that can be present in relevant levels in the must obtained from mildew - infected grapes. This compound is characterized by very low sensory thresholds that can be responsible for the fungus odor in the must (Darriet et al., 2002 ). Normally, during fermentation the molecule is completely reduced to the lesser powerful 3 - octanone by the yeasts, but it was found to be present in dry wines (Culle r e et al., 2006 ).
A method proposed for determination of 1 - octen - 3 - one in wines is by performing an on cartridge derivatization of the sample followed by GC/MS/MS analysis (Culler é et al., 2006 ). A 90 - mL volume of wine is passed through a 90 - mg ethylvinylbenzene – divinylbenzene copolymer SPE cartridge and, after removing the major volatiles by washing with 9 mL of a 40% methanol/water solution containing 1% NaHCO 3 , the analyte adsorbed on the stationary phase is derivatized by passing through the cartridge 2 mL of an O - (2,3,4,5,6 - pentafl uorobenzyl) hydroxylamine (PFBOA) 5 mg/mL aqueous solution. To allow the reaction to occur, the cartridge is kept imbibed with the reagent for 15 min at room
150 VOLATILE AND AROMA COMPOUNDS IN WINES
Figure 5.11. Mechanism of AAP formation proposed by Hoenicke ( 2002b ) . (Reprinted from Journal of Chromatography A 1150, Schmarr ( 2007 ) Analysis of 2 - aminoaceto-phenone in wine using a stable isotope dilution assay and multidimensional gas chromatography – mass spectrometry, p. 79, Copyright © 2006, with permission from Elsevier.)
Figure 5.12. The MS – EI (70 eV) mass spectrum of 2 ! - aminoacetophenone (AAP).
n - heptane as a cosolvent, then dichloromethane is evaporated at room temperature in order to have a residual extract in n - heptane (Schmarr et al., 2007 ).
Alternatively, a direct - immersion SPME method with DVB/CAR/PDMS fi ber (50/30 µ m, 2 cm length) has been proposed. An aliquot of 15 mL of wine is transferred into a 20 - mL vial and equilibrated at 30 ° C for 5 min, then the fi ber is immerged into the solution for 30 min under stirring. The fi ber is then desorbed into the GC injection port at 250 ° C (Fan et al., 2007 ).
ETHYL AND VINYL PHENOLS IN WINES 145
Couto et al., 2006 ). Figure 5.10 shows a scheme for formation of ethylphenols from hydroxycinnamic acids.
Volatile phenols greatly infl uence the aroma of wine, the most important are 4 - vinylphenol (4 - VP), 4 - vinylguaiacol (4 - VG), 4 - ethylphenol (4 - EP), and 4 - ethylguaiacol (4 - EG) (Chatonnet et al., 1992 ). The 4 - EP compound was reported in wine for the fi rst time in 1967 by Webb and co - workers and its presence, together with the other phenols cited, was confi rmed in 1970 by Dubois and Brul é (Webb, 1967 ; Dubois and Brul è , 1970 ).
Oligomer proanthocyanidins inhibit Saccharomyces cerevisiae cin-namate decarboxylase (Chatonnet et al., 1990 ), justifying the very low amounts of vinylphenols in red wines; on the contrary, Brettanomyces decarboxylase is not inhibited by proanthocyanidines (Chatonnet et al., 1993 ). Formation of stable vinylphenol – anthocyanin adducts can arrest the successive formation of ethylphenols in red wines (Fulcrand et al., 1996 ). Also, derivates of vinylcatechol (Schwarz et al., 2003 ; Hayasaka and Asenstorfer, 2002 ), were found in wine.
White wines can contain vinylphenols in concentrations up to several hundreds of a microgram per liter, but they usually lack ethylphenols. On the contrary, in red wine ethylphenols can reach some milligrams per liter (Chatonnet et al., 1992; 1993 ; Chatonnet, 1993 ).
In red wines, high levels of 4 - EP are associated with disagreeable odors described as “ phenolic ” , “ leather ” , “ horse sweat ” , “ stable ” , or
Figure 5.10. Formation of ethylphenols from hydroxycinnamic acids.
OHO
OH OH
CH3OCH3OCH3O
OH
OHO
OH OH OH
Ferulic acid 4-Vinylguaiacol 4-Ethylguaiacol
p-Coumaric acid 4-Vinylphenol 4-Ethylphenol
Hydroxycinnamatedecarboxilase
Vinylphenolreductase
Hydroxycinnamatedecarboxilase
Vinylphenolreductase
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