Transcript
Flavour Chemistry
Dr Kieran KilcawleyDr Kieran KilcawleyTel: 00 353 (0)25 42245/42445Tel: 00 353 (0)25 42245/42445Kieran.kilcawley@teagasc.ieKieran.kilcawley@teagasc.ieflavour.chemistry@teagasc.ieflavour.chemistry@teagasc.ie
Flavour Chemistry
• Flavour comprises of
• ~ 75% Aroma• ~ 25% Taste
Flavour Chemistry
• Peptides, Amino acids, Organic Acids, Sugars, Salt, Nucleotides
• Chemesthesis (touch, heat, cooling, sound)
Sweet Sour Salty Bitter Umami
TASTE
Flavour Chemistry
• Alcohols, Ketones, Aldehydes, Acids, Esters, Thiols, Sulphurs, Phenols, Furans, Pyrazines
AROMA
CITRATE LACTOSE CASEINTRIGLYCERIDE
Galactose Glucose
Tagatose-6-P Glucose-6-P
Dihydroxyacetone-P Glyceraldehyde-3-P
Pyruvate
Diacetyl
Acetoin
Oxaloacetate
Acetate
Vía Leloir
Acetaldehyde
Ethanol
Hydroxy acids
Ácid
β-ketoacids
Peptides
Amino acids
TransaminationDehydrogenation
DecarboxylationReduction
Aldehydes Alcohol Organic acid Aromatic
Secondary alcohol
Methyl ketones
Lactone
Alcohols
Esters
• Biochemistry of cheese ripening
Free fatty acids
Lactate
Flavour Chemistry
Flavour Chemistry
• Aromas from Metabolism of free amino acids
Phenylalanine
Tyrosine
Trypt
opha
n
Methionine Isoleucine
Valine
Leucine
Flavour Chemistry
• State of the Art Flavour Chemistry Facility GCMS
Systems
Euro Award
Flavour Chemistry
• Automated Volatile Extraction/Concentration• Passive Headspace Technique
• Solid Phase Micro-Extraction (SPME)
Flavour Chemistry
• Automated volatile Extraction/Concentration• Dynamic Headspace Technique
• In Tube Extraction (ITEX)
Sample tube
SampleAir space
Pump
Flavour Chemistry•Dynamic Headspace
Technique•Thermal Desorption (TD)
Sample Grab – Pack Sampling
Flavour Chemistry
• Advanced Gas Chromatography Mass Spectrometry• Single & Triple Quadrupole MS Detection
Flavour Chemistry
• Advanced Gas Chromatography Mass Spectrometry
Flavour Chemistry
Cheddar
Danish Blue
Emmental
Urine Fl
oral
Buttery
Woody
Cheesy
Orange peel/Citrus/Floral
Sweet/tallow
Mushro
om-lik
e
Alcoho
l/Frui
ty
Chocolate/Green
Cabbage/Stink Bomb
Earthy/Musty
Caramel/Toffee
Vinegar
Flavour Chemistry• Odour Activity
• Detection Frequency• ~12 untrained panellists• Record duration of each odour plus description• No of detections x duration = Nasal Impact Frequency (NIF)• Resultant Aromagram
• Bigger the rectangle the more important the compound(s)
Chromatogram Aromagram
Woody/Earthy/bark/cresol
Vinegar
Cheesy/socks
cabbage
Caramel/Toffee
Citrus/orange peel
Odour Descriptors
• Sensory & Flavour Chemistry• Identify the key components responsible for
perception• A Chemometrics Approach
• Associations between sensory attributes and volatiles
Flavour Chemistry
Flavour Chemistry• Examples of On-going Dairy Studies
• Flavour potential of lactic acid bacteria• Flavour characterisation:
• cheeses, yoghurts, whey• Preference Mapping in Cheddar cheese• Assessment of volatiles in milk and dairy
produce from cows feed on grass• Reduced fat yoghurts/cheeses• Indices of auto-oxidation in dairy powders
• Flavour Profiling• Product Matching• Identification of key
odorants• Stability studies
• Oxidation• Identification of off-
odours• Identification of chemical
contaminants
Flavour Chemistry
• Service• Consultancy• Contract
Research• Collaborative
ResearchDr Kieran KilcawleyT: 025 42245kieran.kilcawley@teagasc.ieflavour.chemistry@teagasc.ie
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