Quality parameters of sunflower oil and palm olein during multiple frying (original) (raw)
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Heliyon, 2021
The behaviour of high oleic sunflower oil in deep frying process of purple potato Purple Majesty has been evaluated simulating a fast food cooking process. This oil was used for 8h/day for 6 days, filling up from the 2nd day. A discontinuous and prolonged procedure was tested. Free Fatty Acidity (FFA), Peroxide Value (PV), Total Polar Compounds (TPC), Fatty Acid (FA) composition, Volatile Organic Compounds (VOC) have been determined at different times in thermo-oxidized (T-OX) oil, and in frying oil. The FFA in T-OX oil samples showed values in the range 0.09%-0.24%, whereas in the frying oil values varied in a range between 0.09% and 0.16%. TPCs values varied from 1.76% to 38.24% in T-OX oils, whereas in frying oil used for frying purple potatoes (FOPP) showed values in the range from 1.76 to 29.13%. The peroxides values did not follow a regular pattern, both during thermo-oxidation and during frying. Among the Long Chain Fatty Acids (LCFAs), oleic acid was the most represented (84.13%). Short chain fatty acids (SCFAs) amount was 0.34% (octanoic acid). Medium chain fatty acids (MCFA) amount was 4.45% (palmitic acid). During the thermo-oxidation, the poly-unsaturated fatty acids (PUFA) amount decreased during the 48 h of heat treatment, reaching an amount of 6.21%. This determined the increase in short chain fatty acids (SCFA). Trans fatty acids increased with the frying time. Unsaturated fatty acids (UFA) reached the value of 90.19%; SFA was 9.79%, and octanoic acid was 0.20%. A correlation between TPC vs UFA/ SFA and TPC vs C18:2/C16:0 was observed in the frying oil. The most abundant volatile compounds in frying oil (from 0 to 48 h) were the aldehydes produced by decomposition of hydroperoxides of oleic and linoleic acids.
Effect of Frying Process on Physicochemical Characteristics of Corn and Sunflower Oils
This study has been conducted to explore the effect of frying on the physical and chemical characteristics of corn and sunflower oils. For the purpose of this study, corn and sunflower oils and potatoes were obtained from the local market; the oils were reused for frying five days consecutively. After each frying process a sample of oil was taken daily after it cools. The samples were physically and chemically tested, all the physicochemical characteristics were changed. The colour of corn and sunflower oils increased from 0.9 to 6.4 and from 0.4 to 5.1, respectively. Whereas the refractive index of corn and sunflower oils increased from1.4750 to1.4820, and from 1.4750 to 1.4810, respectively. On the other hand, the viscosity of corn oil and sunflower oil increased from 28.7 to 31.0, viscosity of sunflower oil increased from 28.7 to 31.0. The free fatty acids increase in corn oil from 0.125 to 200.0 whereas in sunflower oil they increased from 0.110 to 0.150. In case of peroxide value in both oils the study showed that it was not constant. It worth mentioning here that the frying process followed in this study is the same that is usually used at homes.
Quality Changes of Common Edible Frying Oils during Frying of Traditional Foods
Asian Food Science Journal
This study aimed to examine the impact of the frying process on the physical and chemical properties of widely consumed edible oils. Soybean, palm, and mustard oils, as well as raw dulpuri and singara products, were procured from the nearby marketplace. The oils underwent five consecutive frying cycles at temperatures exceeding 160°C and were subjected to five hours of heating. Analyses including determination of free fatty acid (FFA), peroxide value (PV), saponification value (SV), iodine value (IV), and optical density (OD) at a wavelength of 425 nm were performed. Following multiple rounds of frying and heating, the levels of FFA, PV, and oxidative stability index exhibited an increase, whereas the IV demonstrated a decrease across all three types of oils. The OD of soybean and palm oils exhibited an upward trend, whereas that of mustard oil initially displayed a decline, followed by a gradual ascent. In comparison to soybean and mustard oils, palm oil exhibited the most notewort...
2000
A comprehensive study on the feasibility of use of natural antioxidants, namely rosemary and sage, together with citric acid acting as a synergist during repeated deep-fat frying process of potato chips in palm olein was carried out. The study was inclusive of evaluation of oxidative behaviour of these antioxidants, monitoring of physico-chemical changes of oil during frying, development of some new instrumental methods for detecting quality parameters of used oil, effect of addition of the antioxidants on organoleptic properties of fried product and relationship between quality indices of the oil and sensory acceptability of the fried product.Results showed that rosemary and sage extracts are feasible to be used in retarding the palm olein deterioration during repeated deep-fat frying of potato chips. The two natural antioxidants were proven to significantly (P<0.05) lower the rate of oxidation of the oil during frying, while having very good thermal resistance. Organoleptically...
2013
Background. Understanding of oil deterioration during heating/frying process is important as oils are normally kept hot at commercial food outlets during intermittent frying cycles. An increased level of consumer awareness toward fat composition and its impact on human health could have an effect on selection of fats in the food industry. The rate of quality deterioration during heating depends on fatty acid composition and also the content and composition of minor components. Therefore, the use of more stable frying oils would be desirable. The present study compares the heat stability at frying temperature of regular sunfl ower oil (RSFO) with that of high-oleic acid sunfl ower oil (HSFO). Material and methods. Heating test was carried out at 185 ±5°C for the samples RSFO and HSFO using electric fryer for 8 h/day for 3 consecutive days. The samples were collected every 4 h. The changes in physicochemical properties of the samples were monitored by analytical and instrumental metho...
The study of palm and rapeseed oil stability during frying
Journal of applied botany and food quality, 2018
Palm oil is characterized by high oxidation stability, high smoke point, low foam making properties, limited penetration into the product, what makes it ideal for processes requiring thermal treatment such as frying. The aim of the study was to investigate the chemical composition and thermooxidative stability of red palm olein, rapeseed oil and their mixtures during deep-frying of French fries. Analysis of fatty acids composition and basic parameters of fresh oils (acid number, peroxide value, polar compounds content, induction time) were performed. During frying, changes in acid number, polar compounds in oils as well as consumers’ acceptance of the fries fried in these oils were investigated. During the 32-hour of frying, the lowest chemical changes occurred in palm olein, what was confirmed by low acid values (0.99 mg KOH/g) and low polar content (14.4%). At the end of the experiment, the oil mixture had the highest polar fraction value of 25.0%. In the opinion of consumers, fri...
Journal of the American Oil Chemists' Society, 2009
The effect of repeated deep frying of potatoes versus repeated heating/quenching on the chemical profile of palm oil was investigated. The novelty of the work is that the frying and heating/quenching experiments were conducted under similar time-temperature profiles. The effects of the frying load (potato-to-oil ratio: 1/7 and 1/35 kg potatoes /l oil) and of the time-temperature profile were examined. Whole palm oil and its polar fraction were analyzed using high pressure size exclusion chromatography. Both repeated frying and repeated heating/quenching generated polar and polymerization products in palm oil. Interestingly, no hydrolysis or other decomposition products were generated under any of the examined conditions. The presence of potatoes during frying in palm oil increased the concentration of polymerization products and polar compounds compared to oils without potatoes significantly. The effects of frying load on oil quality depended on frying time. No significant effect of frying load was observed up to frying times of 13 h (or 10 frying batches). However, frying oil quality was affected by frying load once frying times exceeded 24 h (or 20 batches).
STUDY ON THE COMPOSITION AND OXIDATION STABILITY OF SUNFLOWER OIL -OLEIC TYPE DURING HEAT TREATMENT
STUDY ON THE COMPOSITION AND OXIDATION STABILITY OF SUNFLOWER OIL -OLEIC TYPE DURING HEAT TREATMENT, 2021
The monitoring of physicо-chemical changes in the oleic type of sunflower oil when frying potatoes in restaurant conditions by using a professional MModular fryer at 180 °C and comparison with the use of the linoleic typeof sunflower oil was researched. In the oleic type of sunflower oil, there was a slight increase of the AV (acid value) observed till the second frying, after which there was detention within the limits of 0.15 to 0.20 % till the tenth frying.The peroxide value (PV, mеqО 2 /kg) increased significantly in both types of oil-oleic and linoleic, reaching the maximum at the fourth frying, and the value was close to the limiting value for vegetable oils from the linoleic type of sunflower oil-10 mеqО 2 /kg. The induction period in the oleic type of sunflower oil was long-22 hours, but it gradually decreased and after the tenth frying, it was 5 hours. In the linoleic type of sunflower oil, the induction period in the beginningwas 8.55 hours, and after the fourth frying, it decreased to 4 hours.The color numbers according to Lovibondon 10 oil samplesfrom repeated frying of products were determined and this indicator increased with the number of fryings over time.Chlorophyll content was not been established.Theoleic type of sunflower oil produced in Bulgaria, when frying fresh potatoes, was more stable to the oxidation than the traditionally used sunflower oil-linoleic type. Itshowedstability during storage and long frying time of the used products in real working conditions. This made it more suitable for the preparation of food products, culinary items, main courses, starters and garnishes that require longer thermal treatment. This type of product can be recommended for use when frying in the restaurant business and in the area of nutrition. The methods in our research can be used to control the degree of oxidation of frying oils with vegetable origin in their repeated use, by taking samples on the first, fourth and tenth day of frying at different loads of fryers and to test for acidity, peroxide number and color number.
Degradation and Nutritional Quality Changes of Oil During Frying
Journal of The American Oil Chemists Society, 2009
The changes in regular canola oil as affected by frying temperature were studied. French fries were fried intermittently in canola oil that was heated for 7 h daily over seven consecutive days. Thermo-oxidative alterations of the oil heated at 185 ± 5 or 215 ± 5 °C were measured by total polar components (TPC), anisidine value (AV), color components formation, and changes in fatty acid composition and tocopherols. Results showed that TPC, AV, color and trans fatty acid content increased significantly (P < 0.05) as a function of frying temperature and time. The oil polyunsaturated fatty acids (PUFA) decreased in direct proportion to frying temperature and time. After 7 days of frying, the amount of PUFA was reduced by half and the trans isomers contribution increased 2.5 times during frying at 215 °C. Of the parameters assessed, total polar component and color had the highest correlation, with correlation coefficients of 0.9650 and 0.9302 for frying at 215 and 185 °C, respectively. TPC formation correlated inversely with the reduction of tocopherols.
Investigation of the Effects of Repeated Frying on the Quality of Vegetable Oil
American Journal of Applied Chemistry, 2020
Refined vegetable oil (Kings brand), was purchased from Mile 3 Market, Port Harcourt, Nigeria and was repetitively used in frying Akara balls for a period of 24 hours, at intervals of four hours per day, for six days. The effect of heat and repetitive use for frying on quality of the oil was monitored by the measurement of the physico-chemial parameters of the oil after each frying period. The density, % free fatty acid, viscosity, peroxide value and iodine value of the fresh and used oil were determined to investigate the level of deterioration. The results obtained show that the values of the parameters increased with frying time except that of iodine value which decreased with frying time. The free fatty acid value increased from 0.06-.56%, density increased from 0.900-0.910 g/ml, viscosity increased from 23.33-28.31mm 2 /s, peroxide value increased from1.988-4.879meqO 2 /Kg and iodine value decreased from 43.35-29.83wijis. These changes are attributed to the destruction of the chemical structures of the triacylglycerols and formation of new products in the oil by heat. The increase in the density and viscosity shows that as frying progressed, denser and higher molecular weight compounds are formed thereby rendering the used oil more viscous. The increase in peroxide values may be due the formation of peroxides as the primary products of oxidation. The formation of peroxides leads to loss of unsaturation in the oil which is seen as a reduction in iodine value of the oil. The sweet aroma of the oil was also lost as frying progressed as a result of de-esterification of the oil and formation of secondary oxidation products that impart off-flavours to the oil. The findings show that repeated use of vegetable oil for frying leads to deterioration/degration of the oil.