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The Canadian Society for Bioengineering The Canadian society for
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La Société Canadienne de Génie Agroalimentaire et de
Bioingénierie La société canadienne de génie agroalimentaire, de la
bioingénierie et de l’environnement
Paper No. CSBE17142
Performance of Palm Olein During Repeated Frying of Tortilla
Chips
Andrea García-Pérez Abel Cerón-García César Ozuna María Elena
Sosa-Morales
Departamento de Alimentos, División de Ciencias de la Vida,
Campus Irapuato-Salamanca, Universidad de Guanajuato. Carretera
Irapuato-Silao km 9, Ex Hacienda El Copal. Irapuato, Guanajuato,
MEXICO 36500. [email protected]
Written for presentation at the CSBE/SCGAB 2017 Annual
Conference Canada Inns Polo Park, Winnipeg, MB
6-10 August 2017 ABSTRACT Fried products are very appreciated by
the consumers, such as tortilla chips, which are very popular in
North America. The oil employed for the frying of these products is
used in repeated occasions, affecting the quality of the final
product. In order to improve the performance of the oils/fats,
antioxidants are added. Synthetic antioxidants (for example,
butylated hydroxytoluene, BHT) are being replaced by natural
antioxidants; the replacement should be assuring that the
performance will be the similar than the synthetic compound. The
aim of this work was to evaluate the performance of palm olein with
different antioxidants during the repeated frying of tortilla
chips. The tested antioxidants were BHT at 200 ppm (synthetic) and
ascorbyl-palmitate (AP) at 100 ppm (natural) and their blend.
Tortilla dough included 2% sesame. This was sheeted, cut, baked and
fried. Batches of 80 g of tortillas were deep-fat fried at 190°C
for 2 min to produce the chips. Chemical indices, such as free
fatty acids (FFA) and peroxide value (PV), as well as physical
parameters (color) was evaluated. After 20 batches, the values for
olein+BHT were PV=29.6 meq/kg, and FFA=0.19%; for olein+AP were
PV=,13.3 meq/kg and FFA=0.27%; olein+BHT+AP, PV=11.81 meq/kg and
FFA=0.29%. Due to PV was higher than 20 meq/kg, the performance of
olein with BHT as antioxidant is poor, only 1 day of use. The use
of natural antioxidant AP improved the performed of palm olein.
Keywords: palm olein; tortilla chips; frying.
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INTRODUCTION Tortilla chips is a fried product very popular in
North America (Morales-Pérez & Velez-Ruiz, 2010), which are
corn dough-based foods, baked and fried. In the United States is
one of the most popular snack (Kawas & Moreira, 2001). Deep fat
frying is a common process at the industrial, catering and domestic
scales for coking food. Fried foods are very appreciated by
consumers and the food industry, the main reason for this is that
frying is a fast process and different final products can be
prepared, besides gives to food unique organoleptic characteristics
taste, flavor, color, texture and palatability (Saguy & Dana,
2003). The frying process is complex and involves many factors, for
the processing environment itself, characteristics of food and the
type of oil used. Quality of deep-frying food is inseparably of the
quality of the used deep-frying oils (Weisshaar, 2014).
The frying process may be considered as a dehydration process,
when the water and other materials out to the food into the
surrounding oil and the oil take a place into the food. Also a heat
and mass transfer between the oil and the food occur, these
phenomena and the temperature which is mostly between 150 and 190
°C (Gertz, 2014) can promote deteriorative chemical process as
oxidation, polymerization and hydrolysis of mainly unsaturated but
also saturated fatty acids (Matthaus, 2007). Lipid oxidation is one
of the major problem during frying process and in storage of fried
products (Guo, et al., 2016). Palm olein is used extensively in
food industry. It has a competitive price and is more stable at
high temperatures than other edible oils and desirable
physico-chemical properties, as texture, melting point and content
of a relativity high saturated fatty acids (Siddique, 2010)
Autoxidation of lipids is carried out in a free radical chain
mechanism. This chain involves three steps: initiation, propagation
and termination, being cyclical. The primary oxidation products are
formed by the reaction of radical lipids (R∙) with atmospheric
oxygen, called peroxy radical (ROO∙), which react into secondary
oxidation products as aldehydes, ketones, lactones, alcohols, and
acids. These compounds are often related to undesirable odors and
flavors, described as rancidity (Saad, et al., 2007). On the other
hand, the hydrolysis is caused by evaporation of water of food into
the oil, breaking the bond of triacylglycerols, leading
diglycerides, monoglycerides, free fatty acids and glycerol (Saguy
& Dana, 2003) increasing the oil acidity.
In order to retard, reduce or prevent oxidative deterioration,
antioxidants are added to oil. Antioxidants may be classified as
primary and secondary. Primary antioxidant, also called of type I,
are chain-braking antioxidants they can act delay or inhibit the
initiation step or interrupt the propagation step of autoxidation,
some of them are Butylated Hydroxyanisole (BHA), Butylated
Hydroxytoluene (BHT), Tertiary-butylhydroquinone (TBHQ) and
gallates. Secondary antioxidants, are also called of class II, they
act as chelators for prooxidant or catalyst metal ions, provide H
to primary antioxidants, decompose hydroperoxide to nonradical
species, or act as oxygen scavengers. The secondary antioxidants
often enhance the antioxidant activity of primary antioxidants
(Wanasundara & Shahidi, 2005).
The aim of this study was evaluated the performance of palm
olein added with BHT 200 ppm; Ascorbyl-palmitate (AP) 100 ppm, with
synergist effect (Masson et al., 2002); and their blend to improve
the stability of palm olein in frying process to tortilla chips.
Different analytical methods are used to monitoring the changes
which decreased the quality of frying oil (Navas et al., 2007).
MATERIALS AND METHODS Materials. Palm olein added with two
different antioxidants, Butylated Hydroxy Toluene (BHT) 200 ppm,
ascorbyl-palmitate (AP) 100 ppm and their blend, were supplied by
Aarhus Karlshamn, Mexico.
Tortillas chips were made with corn commercial flour and sesame
seed 2% w/w, using for 1 kg of flour, 20 g of sesame blended and
1.83 mL of water, all the ingredients were mixed until obtain a
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homogeneous dough; tortillas were made in a metal press, then
were cut in circles of 4 cm of diameter and finally baked in a
griddle for 60 s. Tortillas chips baked and frying are show in
figure 1. They were storage at fridge until their use.
Figure1. Tortilla chips elaborated with 2% of sesame seed.
Repeated frying procedure. In a commercial electric deep fat
fryer (T-fal) with 3 L of capacity, fresh palm olein was heated
until 190°C, then tortilla chips were fried for 120 s. There was a
total of 25 batches. One batch was 80 g of tortilla. These
conditions were modified from Abdulkarim et al. (2007). The
procedure was repeated for each antioxidant.
Samples. Samples of oil and tortilla chips, were collected at
beginning and from the batches 10, 15, 20 and 25 to each cycle of
frying.
Oil samples analysis. Samples of oil were analyzed for measure
the oxidation and hydrolysis behavior and physical parameters.
Peroxide Value. (PV) The peroxide value is based on the
quantitation of the primary oxidation products, mainly
hydroperoxides, from unsaturated fatty acids. It was determinate
according to the Mexican Standard, NMX-F-154-1987. 1 g of used palm
olein was added with 1 g of potassium iodide (KI) and 20 mL of
acetic acid and chloroform (mixture 2:3) and were shaken until
dissolve, the mix was heated in a water bath for 1 minute and added
0.5 mL of a solution of KI 5%. After a minute, 30 mL of hot water
(18-20 °C) and 2 mL of starch 2% indicator solution were added. The
mix was colored brown, then added sodium thiosulphate (Na2S2O3)
until distinguish visual end-point when the mix turn to a white
color or light yellow. Each test was done in duplicate. The results
are expressed according the next equation
(1) 𝐼𝑃 #$%&'
=)*+,-,./∗1∗233
'
p-Anisidine Value. (AnV) The p-anisidine value, measures the
secondary oxidation products as 2-alkenals and another aldehydes.
It was carried according the manual of the Food Lab Touch Junior
(CDR Foodlab., Florence, Italy), an instrument for rapid methods.
The results were expressed as p-anisidine value according to the
reference AOCS (Cd 18-90).
Free Fatty Acids (FFA)The free fatty acids were carried
according to the standard method AOAC (1984). 3 g of used palm
olein were taken in a flask, 30 mL of isopropyl alcohol were added
to it followed by 2 drops of phenolphthalein. Sodium hydroxide was
added until colored. Each test was done in duplicate. The results
were expressed as % palmitic acid, according the next equation
(2) 𝐴𝐺𝐿 = )*+.7∗1∗3.9:;'
𝑥100.
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Color. The color test was carried in ColorFlex EZ 45/0
spectrophotometer (Hunter Associates Lab., Inc. Reston, VA. Unites
States) at 25°C. The results were expressed as CIE L*a*b* scale.
Each test was done in triplicate.
RESULTS AND DISCUSSION Oxidative deterioration The PV is one of
the most widely used test, and the Mexican Standard stablish as
maximum limit for this parameter 20 meq/kg, after to reach this
value the oil must be discarded. The initial value for the olein
with AP, BHT and AP+BHT were respectively 0, 1.95 and 2.7 meq/kg.
Palm olein with BHT after 20 batches has the highest value 29.612
meq/kg. PV decrease after 25 batches; this is a normal behavior for
PV, as reported by Rady & Madkour (1995), due to after a
maximum level, new secondary compounds are formed. Palm olein with
AP+BHT had lower peroxide values than oleins containing individual
antioxidants.
As oil deterioration continues, the peroxides method is useful
just in the first step of oxidation, does not give information
about the next step. The appropriated method to evaluate secondary
oxidation is p-anisidine reaction Guo et al., 2016). Three
different samples of fresh palm olein have the same AnV of 1.2, the
AnV was increasing through the time in all the samples, the final
values after 25 batches were 4.3 for AP, 4.4 for BHT and 4,5 for
the blended. Guo et al, (2016) reported 1.7 as initial value for
palm olein and palm olein+BHA and values after 5h of frying
potatoes at 180°C of 15.4 y 8.6 respectively. Table 1 shows the
values for oxidative deterioration parameters
Hydrolytic deterioration For Free Fatty Acids (FFA), the maximum
limit is 3% as Mexican Standars establishes. FFA are reported as a
percentage of the majority fraction of fatty acid, in palm olein is
palmitic acid. Palm olein+BHT has lower values than other
antioxidants and olein+BHT+AP has higher. The initial FFA values
were 0.01% for olein+BHT and 0.08% for olein+AP and olein+BHT+AP;
after 25 batches has values of 0.19%, 0.27% an 0.29% respectively,
Figure 2 shows the initial values and after batches 10,15 20 and
25.
Table 1. Oxidative deterioration values for palm olein after
different batches during repeated frying of tortilla chips with 2%
sesame.
Characteristic
Batch
Antioxidant BHT AP BHT+AP
Peroxide value
(meq/kg)
0 1.95 0 2.7
10 13.532±1.3 10.238±1.47 5.390±1.52
15 15.066±1.78 11.920±0.59 8.076±0.63
20 29.612±1.21 13.378±0.64 11.815±1.37
25 12.491±1.39 11.278±0.36 12.160±0.98
p-anisidine value
AnV
0 1.2 1.2 1.2
10 2.7 3.7 2.1
20 3.0 3.7 2.9
25 4.4 4.3 4.5
*PV shows an average of three replicates and their standard
deviation. AnV not has replicates.
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Figure 2. Free fatty acids for palm olein after different
batches during repeated frying of tortilla chips
with 2% sesame.
Color. Color is an important physical characteristic of an oil.
It was measured to evaluated the darkening in oil through frying
time, table 2 shows values for parameters L* (lightness), a*
(redness) and b* (yellowness) for each olein, after batches 10,15,
20 and 25. As well know, in frying process the color of oil becomes
darker, and increases the intensity of red and yellow colors (Rady
& Madkour, 1995). Thus, a* and b* parameters increase and L*
value, which measured lightness, decreases.
Table 2. Hunter parameters of color of palm olein after
different batches during repeated frying of tortilla chips with 2%
sesame.
Parameter
Batch
Antioxidant
BHT AP BHT/AP
L*
10 72.5166±0.45 67.12±1.40 69.56±3.51
15 67.8233±5.19 62.2866±6.98 70.1466±1.59
20 70.7966±0.74 68.5166±3.20 59.4766±2.13
25 71.2633±1.53 59.5666±4.49 63.0366±4.13
a*
10 -4.46±0.18 -3.84±0.28 -4.3±0.67
15 -3.44±1.04 -2.4866±1.68 -4.1266±0.20
20 -3.8966±0.12 -3.86±0.61 -1.7633±0.49
25 -4.02±0.16 -1.6466±1.12 -2.21±0.83
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b*
10 49.7166±1.5 46.6866±1.16 46.1166±1.02
15 50.0533±1.67 47.7266±1.27 46.8433±0.99
20 46.5066±5.62 47.35±0.72 48.2533±0.70
25 49.9066±0.81 49.0966±0.99 48.5333±0.34
*Values show an average of three replicates and their standard
deviation.
CONCLUSION. The best performance of palm olein was observed when
a blend of antioxidants 200 ppm BHT + 100 pm ascorbyl palmitate
were used for the repeated frying of tortilla chips, made by corn
flour and 2% of sesame seed. When 200 ppm of BHT was employed as
antioxidant, the peroxide values exceeded the permitted value for
this index. More antioxidants should be studied in order to extend
the performance of palm olein when is used for repeated frying of
tortilla chips, as these chips are a valuable product in the
market.
Acknowledgements. Authors thank to EDUCAFIN, CONACYT and
Presidency of Campus Irapuato-Salamanca for financial support.
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