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Philippine Journal of Science 148 (4): 587-595, December 2019 ISSN 0031 - 7683 Date Received: 24 April 2019

Physicochemical Characterization of Used from Vacuum of (Artocarpus heterophyllus Lam) Pulp EVIARC Sweet Variety as Affected by Frying Cycle

Jason D. Braga1, Roberta D. Lauzon2, and Lorina A. Galvez2*

1Institute of Food Science and Technology College of , Food, Environment, and Natural Resources Cavite State University, Indang, Cavite, Philippines 2Department of Food Science and Technology College of Agriculture and Food Science, Visayas State University Baybay City, Leyte, Philippines

This study was conducted to determine the quality of (CO) used in a 2-h jackfruit pulp vacuum frying for 20 frying cycles. The % free (FFA), acid value (AV), peroxide value (PV), moisture content (MC), and color of the CO used in vacuum frying was determined for unheated oil and oil after the 1st, 5th, 10th, 15th, and 20th cycle of frying. The FFA (0.273–0.554%), AV (0.543–1.102 NaOH/kg oil), PV (4.983–45.739 meq oxygen/kg), and MC (1.016–1.079%) showed significant increase (p < 0.05) in the oil as the number of frying cycle increased that dictated the quality of the used CO. Hunter L and b showed significant (p < 0.05) effect on oil as the number of frying cycle increases, while Hunter a indicated insignificant effect. Based on the standard set by the Codex Alimentarius Commission (CAC) for refined CO (10 meq O2/kg oil), the oil quality is still safe after the third frying cycle, which conforms with the set standards for PV and AV. The pairing of these two tests is a good measure of oil quality assessment.

Keywords: coconut oil, moisture content, physicochemical quality, recycling of oil

INTRODUCTION which consist of three fatty acids and one molecule of glycerol. The minor components of are Vegetable oil (crude, refined, bleached, and deodorized) FFAs, -soluble vitamins, pigments, phospholipids, is one of the main dietary components in the day-to-life , sterols, and fatty alcohols (Foster et al. 2009). food consumption and is used in nearly all types of food Vegetable contain different kinds of fatty acids and their preparations – including frying, , sautéing, dressing, compositions are widely varied; however, one type of fatty marinating, and extrusion . They are generally acid is generally predominant over the other fatty acids. obtained from oilseeds (i.e., , sunflower, cottonseed, The physical and chemical characteristics of vegetable oils corn, and coconut); food legumes (i.e., , ); are influenced by the quantity of fatty acid and the place, nuts (i.e., ); or the soft substances of fruits (i.e., where it is positioned on the glycerol moiety (AOCS 2006). olives). They are primarily composed of triacylglycerols, Although conventionally named as oil, CO is actually *Corresponding Author: [email protected] a fat as it is majorly composed of saturated fatty acids

587 Philippine Journal of Science Braga et al.: Physico-chemical Characterization Vol. 148 No. 4, December 2019 of Used Coconut Oil

(92%), from which 62% corresponds to fatty acids with and preserves nutritional compounds such as vitamins carbon number between 8 and 12 (Eyres et al. 2016). and minerals (Da Silva and Moreira 2008). CO belongs to a unique group of named lauric oils, where (12:0) is the major fatty acid present in However, the most popular issue in frying is the repeated its composition. oil and are also heating of cooking oil and using it several times. part of this group. Some researchers believe that lauric oils Consumption of oxidized products, as a result of repeated have unique properties, once they behave very differently use of oils in frying processes, causes potential health in the metabolism compared with fats majorly composed hazards (Gotoh et al. 2007). Repeatedly heating of oil may by long-chain fatty acid (Dayrit 2014). not be common to some household cooking; nevertheless, it is more common in business establishments such as fast- A portion size of 100 g of CO contains 890 kcal and food chains, restaurants, and food companies because it can 82.5 g of (Mansor et al. 2012). , , help reduce production expenses and earns more profit. and present a much lower concentration of this type of fatty acid (51.2, 39, and 49 g, respectively) and Since there is little information of oil quality assessment fewer calories (717, 900, and 884 kcal, respectively) for of frying under vacuum condition; hence, this study was the same portion size (Mansor et al. 2012). In addition, conducted to determine the quality of CO used in a 2-h CO lacks essential fatty acids, which are present in other jackfruit pulp vacuum frying for 20 frying cycles. vegetable oils used in cooking such as (7% linolenic acid and 51% ), flaxseed oil (53% linolenic acid and 13% linoleic acid), and (9.1% linolenic acid and 18.6% linoleic acid) (Mansor MATERIALS AND METHODS et al. 2012). Also, compared with palm oil, CO is low on bioactive compounds. Crude palm oil contains a total Procurement of Raw Materials carotenoid content of 500–700 mg/l (Posada et al. 2007), Mature (120-d old) jackfruit (Artocarpus heterophyllus which is not present in virgin CO. Regarding , Lam.) – specifically the EVIARC Sweet variety – used virgin CO contains around 38 mg/kg whereas palm oil in the production vacuum fried pulp was procured at has 600–1260 mg/kg (Mansor et al. 2012). Mahaplag, Leyte, Philippines. The fruit was stored in a dry area with ambient temperature (25–30 °C) for 7 d prior to Frying is a commonly used method in food preparation. processing. Refined, bleached, and deodorized (RBD) CO Nowadays, fried foods are popular from household to produced by International Pharmaceuticals Incorporated restaurants and even in goods available in the supermarket was purchased from Ormoc City, Leyte, Philippines. shelves. of foods at high temperature creates the welcoming special flavor, golden brown color, and crispy texture – making the food appealing, good smelling, Production of Vacuum-fried Jackfruit and very palatable. It is noted that frying causes the oil The fruit was washed, brushed, and rinsed with 10 ppm to undergo hydrolysis, oxidation, and thermal reaction; sanitizing solution; cut into half; de-pulped; and de- consequently, numerous by-products such as FFAs, seeded. The pulp (4 kg) was blanched for 1 min at alcohols, cyclic compounds, dimers, and polymers (Tabee temperature. The blanched sample was cooled and then et al. 2009) can be produced. stored in the freezer –18 °C overnight. RBD CO (21 L) was heated first until 120 °C in a vacuum frying system Vacuum frying offers an alternative way to improve (KVF – 5K – GH of P. Kuizon Enterprises, Philippines) the quality of fried fruit and vegetables other than by before placing 4 kg of unthawed frozen pulp in the oil atmospheric frying (Dueik and Bouchon 2011). The and then vacuum fried at 89 ˚C at 28–30 in-Hg vacuum main factors that influence fried products are the frying (Brand-Speroni) for 2 h and 10 min. The temperature was time-temperature combination of the cooking process, the maintained using the fryer’s thermostat, which controls the correct combination of which is necessary to produce a solenoid valve. After that, the vacuum fried jackfruit pulps food product with acceptable physical attributes (Andrés- were spin-dried to remove excess oil. Finally, the vacuum Bello et al. 2010). Dueik and Bouchon (2011) showed that fried pulp was band-sealed and packed in aluminum foils. vacuum frying significantly lowered the final oil content The frying protocol was continued without a cooling in comparison to atmospheric fried vegetables, and it also period for three cycles of 4 kg fruit per cycle per day for slowed the rancidity of the oil. Most of the benefits of a total of 20 cycles. Some oil was lost when it is absorbed vacuum frying from the low temperatures used and the by the product and some went to the condenser during minimal exposure to oxygen, which reduces the adverse boiling. The oil that was lost was not replenished. Samples effects on the oil quality (Shyu et al. 1998), preserves (oil) for each frying cycle were taken for analysis. the natural color and flavor (Shyu and Hwang 2001), decreases the acrylamide content (Granda et al. 2004),

588 Philippine Journal of Science Braga et al.: Physico-chemical Characterization Vol. 148 No. 4, December 2019 of Used Coconut Oil

Sample Collection and Preparation of oxygen per kg. Forty (40) mL of fresh (unused) CO and used oils from vacuum frying cycles 1, 5, 10, 15, and 20 were kept in a Statistical Analysis covered amber glass bottle and stored in the refrigerator A triplicate reading in every analysis of each treatment (4 °C) to maintain the quality of the oils. Oil samples was carried out. Data was analyzed statistically through from cycles 1, 5, 10, 15, and 20 of vacuum frying were one-way ANOVA with Tukey’s Honestly Significant collected hot, right after each frying cycle, and cooled Differences post hoc test for differences between pairs of down in covered bottle for 5 min before storage. means using the commercially available software, SPSS 17 software program (SPSS Inc., Chicago, IL, USA). A MC Determination p-value of less than 0.05 (p < 0.05) indicates statistical The MC was determined using AOAC method (1990) significance. by measuring 2 g of the CO sample into an already dried and pre-weighed crucible. The crucible containing the oil was placed in a hot air oven at 105 °C for 4 h. It was then cooled and placed in a desiccator and re-weighed. RESULTS AND DISCUSSION The MC on wet basis was calculated using the formula:

mass (g) of sample before drying MC The MC of food can, therefore, be determined accurately Moisture (%) = – mass (g) of sample after drying x 100 mass (g) of sample before drying by measuring the number or mass of water molecules present in a known mass of sample. The MC of the oil samples ranged from 1.018 ± 0.002 % to 1.079 ± 0.003 Color Measurement %, which shows significant (p ≤ 0.05) effect. The MC of Colorimeter application was used to determine the unused, (cycles 1, 5, and 10) oils were not significantly difference in the color of oil samples from different frying different (p ≤ 0.05) from each other, while cycle 10, 15, cycles. The color was expressed in terms of L* value and 15 oil samples were significantly different (p ≤ 0.05) [lightness, ranging from zero (black) to 100 (white)]; a* from each other (Table 1). There was a fluctuation on the value [ranging from +60 (red) to −60 (green)]; and b* MC of oil samples as the frying cycle progressed. This value [ranging from +60 (yellow) to −60 (blue)]. may be due to the actual sampling of oil directly from the vacuum fryer wherein the water and/or moisture left at the nozzle of the oil outlet has been collected before AV and FFA Determination the oil passed through it; possibly, the container was not FFA content was determined using the method of AOCS tight enough to create a relatively vacuum environment (1993). A 25 mL mixture of diethyl ether was mixed for the collected oil samples and, lastly, the series of with 25 mL ethanol and 1 mL of 1% phenolphthalein opening and closing of the sampling container after the and carefully neutralized with 0.1 N sodium hydroxide oil had been collected. (NaOH) solution. About 2 g of the oil sample was weighed into an Erlenmeyer flask and was added with neutralized The increasing MC of the oil used in vacuum frying was diethyl ether: ethanol mixture. The solution was titrated due to moisture coming from the jackfruit pulp being with aqueous 0.1 N NaOH to a faint pink endpoint that vacuum-fried, with 4 kg of jackfruit pulp per vacuum persisted for 15 s. The FFA was expressed as % frying cycle with no addition of oil being used since first while AV was expressed as % FFA multiplied by 1.99. vacuum frying cycle. A 100-g portion of the jackfruit pulp contains 72–94 grams water or moisture (Haq 2006). Determination of PV The PV was evaluated according to the method of AOAC Color (1995) with slight modification. A 20 mL of solvent Hunter lightness (L) value. The Hunter L value is a mixture (two volumes of glacial acetic acid + one volume critical parameter in the frying process and is considered as of chloroform) was added to 1 g of the oil sample in a 125 a primary quality factor evaluated by the consumer when mL Erlenmeyer flask with vigorous swirling. Thereafter, considering the product quality. The Hunter L values with 0.5 mL of saturated potassium iodide solution was added respect to different frying cycles are shown in Table 1. The to the flask with vigorous shaking and was allowed to L value of fresh (unheated) oil sample was 75.2 ± 2.8 and stand for at least a minute. Afterward, 30 mL of distilled for cycle 20, the L value was 49.6 ± 9.9. This decrease water was added and the solution was titrated against 0.1 in value is statistically significant (p ≤ 0.05) as shown in N sodium thiosulfate solution with 5 mL starch solution Table 5. The 20th frying cycle oil sample was the only as indicator. The PV was expressed as milli-equivalent one significant (p ≤ 0.05) between and among all other

589 Philippine Journal of Science Braga et al.: Physico-chemical Characterization Vol. 148 No. 4, December 2019 of Used Coconut Oil

Table 1. MC and color of CO used in vacuum frying of jackfruit pulp as influenced by frying cycle. Color Treatment % MC* L* ans b* Cycle 0 (unused) 1.020 ± 0.002d 75.2 ± 2.8a –3.8 ± 0.5 9.5 ± 0.7c Cycle 1 1.022 ± 0.002d 69.7 ± 2.7a –3.7 ± 0.8 9.2 ± 2.1c Cycle 5 1.018 ± 0.002d 74.1 ± 1.5a –4.5 ± 1.0 15.2 ± 0.9b Cycle 10 1.016 ± 0.002cd 71.4 ± 3.5a –4.5 ± 1.0 21.8 ± 0.6a Cycle 15 1.046 ± 0.003b 67.2 ± 0.4a –3.8 ± 0.1 21.9 ± 2.7a Cycle 20 1.079 ± 0.003a 49.6 ± 9.9b –2.5 ± 1.0 18.500 ± 3.6ab Mean ± standard deviation of replicate analysis (n = 3) Values with the same superscripts within the column are not significantly different (p < 0.05). *Significant at p < 0.05; nsnot significant at p ≤ 0.05 oil samples (Table 1). Low lightness values resulted in a towards positive (+), which means that the yellowness dark color and are formed due to non-enzymatic browning of the oil tends to intensify as the number of frying cycle reactions. The lightness values above 60 were referred increases (Figure 1). to as excellent; 56–60 as acceptable and below 50–55 as marginally acceptable (Pangloli et al. 2002). This change The unused CO was colorless since it was refined and in lightness values may be attributed to the loss of MC bleached. The possible cause of the color change of the oil and browning that took place during frying as a result is due to the presence of carotenoid in jackfruit pulp that of acrylamide formation and non-enzymatic browning gives its characteristic yellow color. Jackfruit contains many reaction (Pedreschi et al. 2005, 2007). carotenoids, including all-trans-β-carotene – an important antioxidant for human health. The main carotenoids in Hunter redness (a*) value. The redness value of the jackfruit were shown to be all-translutein (24–44%), all-trans- oil samples ranged from –2.5 ± 1.0 to –4.5 ± 1.0. It was β-carotene (24–30%), all-transneoxanthin (4–19%), 9-cis- found out that the redness increased initially followed by a neoxanthin (4–9%), and 9- cis-violaxanthin (4–10%) (De decrease (Table 1) as the number of frying cycle increases Faria et al. 2009). Thermal processing may result in losses of but is not significant (p ≤ 0.05). The color of the oil samples all-trans-carotenes and the formation of cis isomers. In fact, from unused form until cycle 20 went in the direction of a in the percentage of all-trans-β-carotene with the becoming green since the a* value of the 20th frying cycle concomitant increase of 13-cis and 9-cis isomers had been oil is –2.5 ± 1.0 based from the reference scaling of a* value observed during processing (Chandler and Schwartz 1988). [ranging from +60 (red) to −60 (green)]. Carotenes can be found in many dark green and yellow Hunter yellowness (b*) value. The Hunter b value, which leafy vegetables and appear as fat-soluble pigments, ranges from 9.167 ± 2.120 to 21.933 ± 2.656, was found while β-carotene can be found in yellow, orange, and to be significant. There was no specific trend of change red-colored fruits and vegetables (Holden et al. 1999). in Hunter yellowness value with respect to the number Naturally, β-carotene is mostly found as all-trans isomers of frying cycles (Table 1). The color of the oils is going and lesser as cis-isomers, with the relative abundances

Figure 1. Color of oil used in vacuum frying of jackfruit pulp as influenced by frying cycle.

590 Philippine Journal of Science Braga et al.: Physico-chemical Characterization Vol. 148 No. 4, December 2019 of Used Coconut Oil in the following order: all-trans > 9-cis > 13-cis > 15-cis factor that significantly affects the use of oil for industrial (Guo et al. 2008). applications or human nutritional purposes (Akinyeyea et al. 2011). The AV ranges from 0.543 ± 0.012 to 1.102 ± All-trans-β-carotene is very unstable and can be easily 0.022 mg NaOH/g oil. According to the CAC standard of isomerized into cis-isomers when exposed to heat and refined oils, the CO used in this study should be 0.6 mg light. Isomerization energy is involved in the relocation NaOH/g oil (CAC 2006). The sample from the 20th frying of the single or double bond of one form of carotenoid cycle did not conform to the standard. The significance into another (Kuki et al. 1991). A study had been carried of the oil samples followed the same trend with the % out to determine the isomerization energy of carotenoids, FFA wherein the oil sample from cycle 20 was found to especially neurosporene, spheroidene, and spirilloxanthin be statistically significant (p ≤ 0.05) among all samples (Niedzwiedzki et al. 2009), but the excited energy stages (Table 2). As the number of frying cycle progresses, the are not well understood. Besides, processing of fruit could acid value of oil also progressively increases. result in significant cis-trans isomerization of β-carotene, which was shown by the formation of 13-cis-β-carotene (Vásquez-Caicedo et al. 2007). Table 2. Chemical analysis of oil used in vacuum frying of jackfruit In regard to the effect of processing and isomerization of pulp as influenced by frying cycle. carotenoids in fruits and vegetables, 13-cis-β-carotene is PV (meq Treatment % FFA* AV* the main product of geometric isomerization (Lozano- oxygen/kg)* Alejo et al. 2007); 9-cis-β-carotene is formed when Cycle 0 exposed to light (Schieber and Carle 2005, Lozano-Alejo 0.273 ± 0.006a 0.543 ± 0.012a 4.983 ± 1.000a et al. 2007); while 13-cis-α- and β-carotene isomers are (unused) formed during storage (Tang and Chen 2000). A study Cycle 1 0.274 ± 0.001a 0.545 ± 0.010a 7.528 ± 0.521a on the effect of β-carotene isomerization due to reflux Cycle 5 0.276 ± 0.005a 0.548 ± 0.002a 14.587 ± 2.271b heating has exhibited that degradation occurs to all- Cycle 10 0.276 ± 0.006a 0.549 ± 0.011a 20.062 ± 1.47c trans-β-carotene, with a significant increase in 13-cis- Cycle 15 0.279 ± 0.002a 0.555 ± 0.003a 24.484 ± 1.018d β-carotene (Chen and Huang 1998). Marx et al. (2003) b b e have revealed that in pasteurized and sterilized samples, Cycle 20 0.554 ± 0.011 1.102 ± 0.022 45.739 ± 2.018 13- cis-β-carotene was the only isomer formed during Mean ± standard deviation of replicate analysis (n = 3) Values with the same superscripts within the column are not significantly different pasteurization and sterilization of carrot juice, while (p < 0.05) 9-cis-β-carotene was probably formed during *Significant at p <0.05; nsnot significant at p ≤ 0.05 of sterilized carrot juice. Moreover, 9-cis- and 13-cis-β- carotenes were thought to originate independently from cis precursors by non-enzymatic isomerization of all-trans In the study of Basuny et al. (2012), acid value during forms (Breitenbach and Sandmann 2005). vacuum frying of samples increased slightly with frying time compared with atmospheric frying On the other hand, cis-β-carotene has been shown to sunflower oil which increased strongly significantly (p < isomerize into all-trans-isomer when heated and exposed 0.05) with frying time. to air (Qiu et al. 2009). It shows that the isomerization of β-carotene occurs instead of degradation. The isomerization During frying, fats and oils are oxidized to form process was also known to occur when a crystalline hydroperoxides that can decompose further to yield the β-carotene is heated at 90 °C and 140 °C in a nitrogen secondary oxidation products such as alcohols, ketones, environment, which might be due to the partially melted aldehydes, and acids. In deep-fat frying, however, acids β-carotene that has increased the probability of cis- to all- are also produced by hydrolysis – the reaction of fat with trans-β-carotene isomerization (Qiu et al. 2009). Carotene water was to form FFAs (Shyu et al. 1998). in all-trans form has higher bioavailability than its cis FFA content is an index of lipase activity and an indicator counterpart, while β-carotene and β-apo-12’-carotenal have of freshness, storage time, and stability of many fat-rich the highest bioconversion rate at 100% and 120% (on a foods. It is a known fact that FFAs are more susceptible to weight basis), respectively (Castenmiller and West 1998). lipid oxidation, leading to reduced , rancidity, and production of off-odor compared to intact fatty acids AV and FFA in the triglycerides. FFA has been reported to play a very AV is the number of milligrams of KOH required to important role in the aroma and flavor, and also contributes neutralize the FFAs present in 1 g of edible oil. It is used to the organoleptic quality of foods when present in for detection of hydrolytic rancidity because it measures adequate concentration (Rosa et al. 1994). the amount of FFAs present (Yadav 2018). The AV is also a

591 Philippine Journal of Science Braga et al.: Physico-chemical Characterization Vol. 148 No. 4, December 2019 of Used Coconut Oil

As shown in Table 2, the lowest % FFA is 0.273 ± 0.006, 1998). The unsaturated fatty acids present in the oils easily which is from the fresh (unused) form of oil, while the react with atmospheric oxygen and form hydroperoxides. highest is 0.554 ± 0.011 from the oil of the 20th frying cycle. There was no significant difference (p ≤ 0.05) on oil Normally, COs exhibit high oxidative stability due to the samples of cycles 0 (unused), 1, 5, 10, and 15. However – presence of large amounts of saturated fatty acids (> 91%). as the oil had been used for up to 20th times – the % FFA However, the PV of all samples ranges from 4.983 ± 1.000 gradually increased, which makes cycle 20 significantly to 45.739 ± 2.018 meq oxygen/kg oil. Statistically, unused different (p ≤ 0.05) from the rest of the samples. and 1st frying cycle sample are not significantly different (p < 0.05) since the PVs are not far from each other. These The increase in FFA (0.273–0.554%) could be attributed two (fresh and cycle 1) PVs (Table 2) were the only values to oxidation and hydrolysis. FFA contents in frying oil that fall within the acceptable PV, which is 10 meq oxygen/ increase with the number of frying cycles (Chung et al. kg of refined oils as set by the CAC (2006). Basically, these 2004). Moreover, the % FFA increased with an increase are the only samples that are safe quality-wise. Interpolating in time of deep-frying, which was attributed to hydrolysis the given values of 1st and 5th frying cycle in terms of the (Naz et al. 2005). During cooking, hydrolysis of oil occurs PV and the acceptable 10 meq oxygen/kg of refined oils, in the beginning when moist food is fried in hot oil. This the oil should be used until the 3rd frying cycle only. reaction enhances the AV of oil because of fatty acid production from triglycerides. Oxidation of oil during On the other hand, oil samples from cycles 5, 10, 15, and frying is the key of concern. Oxidation occurs due to 20 (Table 2) were found to exceed the allowable PV set for reaction with the atmospheric oxygen. Auto-oxidation can quality safety. These samples were significantly different also occur even though the oil is not heated; this process (p ≤ 0.05) from each other. The PVs of cycles 5, 10, 15, is supported by external temperature or exposed to UV and 20 increase abruptly as the number of frying cycle light (Gotoh et al. 2007). increases. These variations can arise from different factors such as the degree of saturation of the fatty acids present The amount of FFA in fats and oils is a good indicator in the particular oil, storage, exposure to light, and the of the extent of its deterioration due to hydrolysis of content of metals or other compounds that may catalyze exposed triglycerides and oxidation of fatty acid double the oxidation processes (Choe and Min 2006). bonds during frying process (Abdulkarim et al. 2007). It is known that CO is predominantly saturated oil due The PV showed significant correlations with the to its high percentages of lauric, myristic, and palmitic concentration of the five aldehydes (t-2-heptenal; acids (Dayrit 2003). Increase in FFA could be attributed t-2-octenal; t-2-decenal; t,t-2,4-decadienal; and t-2- to MC of jackfruit pulp that accelerates the hydrolysis undecenal) and the total concentration of odorants under of oil. It is known that water can promote the hydrolysis different storage conditions (Shiozawa et al. 2007). It was of triacylglycerols to form a combination of mono and found that the five unsaturated aldehydes in oxidized oils diacylglycerols, glycerol, and FFAs (Velasco et al. 2008). are highly cytotoxic. Based on their chemical structures, these aldehydes may show similar extents of toxicity. In Heating cooking oil beyond a particular temperature may fact, t-2-decenal; t,t-2,4-decadienal; and t-2-undecenal change its physicochemical characteristics (Oboh et al. have been reported to be harmful to the skin – while t,t-2,4- 2014, Falade and Oboh 2015). However, the resistance decadienal shows mucosal toxicity (Müller et al. 1996). and stability of different cooking oils to thermal oxidation varies as this is dependent on their fatty acid compositions, wherein oils with higher polyunsaturated fatty acids are more prone to thermal oxidation (Vaskova and Buckova CONCLUSION 2015); those with higher saturated fat such as palm oil The quality of oil used in the production of vacuum fried are capable of withstanding heat at high temperatures jackfruit pulp was significantly affected by the number (Matthäus 2007). Falade and Oboh (2015) discovered that of frying cycles. The % FFA, AV, and PV – as the indices thermal oxidation induced lipid peroxidation and caused for oil quality evaluation – have a significant effect on the changes in the physicochemical properties (AV, PV, and quality changes of CO used in vacuum frying. PV is one iodine value) and β-carotene content of arachis oil. of the most important indices for quality evaluation of oil since the values significantly affect between and among all PV other oil samples as the number of frying cycle increases. PV is one of the most widely used chemical tests for the Based on the standard set by the CAC for refined CO, determination of the quality of fat and oil. The PV is a the quality of oil after three cycles of vacuum frying the measure of rancidity in its early stage and shows good jackfruit still conforms to the set standards for PV and AV. correlation with organoleptic flavor scores (O’Brien This is important for the welfare of the consuming public.

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