• Journal of the Korean Society of Food Culture
• /
• v.21 no.6
• /
• pp.679-684
• /
• 2006

In this experiment, I used three samples of oils. The oils that I used were hydrated soybean oil, pure soybean oil and regular soybean oil. The group of rice was fried in the each sample of oil that had not been used for a few seconds. Rice was used after frying at 230-235$^{\circ}C$ every four hours terms and total frying hours was 12 hours. The hydrated soybean oils was least affected in rancidity. The other two oils were more affected in rancidity than the hydrated soybean oil. However, the trans fatty acid in hydrated soybean oil was 36.5%. The diameter of the poped rice that was fried in pure soybean oil and regular soybean oil that had been used 12 for hours was reduced while the diameter of the popped rice fried in the hydrated soybean oil was not reduced. Also, the groups of rice fried in the pure and the regular soybean oil that had been used for 12 hours reduced the hardness in rice while the group that fried in the hydrated soybean oil at the 12th hour kept the hardness well. In sensory evaluation, rancidity order was found apparently in the pure soybean oil that had been used for 12 hour and in the regular soybean oil that have been used for eight hours and 12 hours. Only the hydrated soybean oil did not have distinctive rancidity order at all. The degree of the crispiness was reduced in the pure soybean oil and in the regular soybean oil at 12th hour frying. However, the hydrated soybean oil preserved the crispiness well until the end of 12 hours of frying. In overall preference test, the pure and regular soybean oil that had been used for 12 hour were not preferable. In conclusion, I found that the group fried in the hydrated soybean oil was better in every evaluation than the groups fried in the pure soybean oil and in regular soybean oil. The hydrated Soybean oil may be better to be used in food manufacturing if the trans fatty acid in the hydrated soybean oil can be reduced.

• Journal of the East Asian Society of Dietary Life
• /
• v.21 no.5
• /
• pp.723-730
• /
• 2011

Soybean oil used to fry French fries, chicken nuggets, and donuts was exposed to high temperature at $180^{\circ}C$ for 72 h. The effects of frying foods on the thermooxidative stability of soybean oil were evaluated by determining the contents of free fatty acids, peroxides, total polar compounds, and conjugated dienoic acids, and by analyzing dielectric constant, refractive index, iodine value, smoke point, and fatty acid composition. The contents of free fatty acids, total polar compounds, conjugated dienoic acids, dielectric constant, and refractive index increased, whereas iodine value, smoke point, and U/S ratio of fatty acids composition decreased with frying time. All samples of frying oils after 72 h presented free fatty acid contents of below 2.0% and total polar compounds of below 25%, which were within the legal limits. However, peroxide values of frying oils were not directly correlated with frying time. The type of fried food affected the thermooxidative stability of the frying oils, with chicken nuggets being more stable in thermooxidation than French fries and donust. Among physiochemical indicators of frying oil quality, a rapid method including dielectric constant and refractive index can be used in quantity food production.

• Proceedings of the Korean Journal of Food and Nutrition Conference
• /
• 2002.06a
• /
• pp.33-33
• /
• 2002

• Korean Journal of Food Science and Technology
• /
• v.52 no.1
• /
• pp.46-53
• /
• 2020

Carrots were deep fat fried with sunflower oil (SO), palm oil (PO), and a blend of palm and sunflower oils (PSO with PO:SO as 2:8 or 4:6) at different temperatures (180 and 190℃) and lengths of time (0.5 to 2.5 min). The quality of deep fat fried carrots was determined by the moisture and fat content, color, conjugated dienoic acid (CDA), hydroperoxide, p-anisidine value, and fatty acid composition. The moisture content of fried carrots decreased with increasing frying time, while the fat content increased. The CDA and p-anisidine values of carrots fried with SO were higher than those fried with PO because of greater unsaturated fatty acids content in SO. PSO was a better choice than SO or PO for deep fat frying carrots in the aspects of oxidative stability and ratio of unsaturated to saturated fatty acids. These results indicate that the quality of deep fat fried carrots depends on the type of oil and frying temperature used, as well as the length of time.

• Journal of the East Asian Society of Dietary Life
• /
• v.20 no.4
• /
• pp.536-542
• /
• 2010

In this study, we determined the fat content, total fatty acid composition, trans fatty acid (tFA) content, and acid value of twenty samples of sweet-and-sour pork and fifteen samples of used frying oils collected from Chinese restaurants in Seoul. After the extraction of crude fat by the Folch method, the total fat content of the twenty sweet-and-sour porks ranged from 9.93 to 20.04%. The total unsaturated fatty acid content ranged from 50.05 to 81.22%, which mostly consisted of oleic and linoleic acid, while those of total saturated fatty acids were 18.06~49.26%. The tFA content of all of the twenty sweet-and-sour porks tested was less than 0.24 g per 100 g of food. The acid values of the fat extracted from the twenty sweet-and-sour porks ranged from 0.44 to 4.37. In the used frying oils, the ranges of the major compositional fatty acids were as follows: palmitic acid, 4.47~20.28%; oleic acid, 23.43~77.45%; linoleic acid, 5.6~53.06%; stearic acid, 1.81~7.38%. The tFA content in all of the fifteen used frying oils was less than 0.98 g per 100 g of fat, while the acid values of the fifteen used frying oils ranged from 0.27 to 2.41.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.4
• /
• pp.564-573
• /
• 1997

The addition of antioxidants to fats and oils is one of the most effective ways to prevent oxidation of lipids. The popularity of natural antioxidants has increased because of the possible toxicity of synthetic antioxidants. Common natural antioxidants, tocopherols, retard oxidation at ambient temperatures, but they are ineffective at retarding oxidation at frying temperatures. The need for the development of novel natural antioxidants which are effective at frying temperatures is obvious. Sterols present in vegetable oils and certain herbal plant extracts have been reported to have antioxidant properties. Some sterols have been shown to retard thermal changes at frying temperatures. All the sterol effective at preventing oxidation at frying temperatures have an ethylidene group in their side chain. These effects can be explained by the hypothesis that sterols with a structure that allows them to react with lipid free radicals to form relatively stable free radicals are effective as antioxidants. (Key words :natural antioxidants, sterols, ethylidene group, herbal plant extracts)

• Journal of the Korean Society of Food Culture
• /
• v.13 no.1
• /
• pp.27-35
• /
• 1998

Consumption of edible oil at food service institutions in Inchon was surveyed to provide basic data for continuous education of dietitians. Manufacturing industry was the major food service institution(78.8%) in Inchon followed by schools, hospitals and social welfare service centers. Most dietitians were at the age of twenties and college graduates with professional careers of 1-5 years. Oil was purchased on the basis of its quality within 1-3% of total food costs four times a month. Proper frying temperature was determined by dropping salt or food coating materials into the oil. Soybean oil was the most frequently used and commercial frying mix powder and flour and eggs in water were the most common food coating materials. Fish and commercial frozen foods were the most frequently used materials for frying. Fried foods were stored with covers in a basket and consumed within 30 minutes after cooking. Frying oils were used one more time after filtering and color was the index for determination of re-use.

• Journal of ILASS-Korea
• /
• v.16 no.1
• /
• pp.15-26
• /
• 2011

In this article, spray characteristics in CI engines fuelled with vegetable oils and its derivatives will be reviewed. Of edible vegetable oils, soybean oil and rapeseed oil were mainly investigated. Of inedible vegetable oils, jatropha oil and used frying oil were main concern on the research on the spray characteristics in CI engine. Spray angle and spray penetration were mainly examined among the macroscopic spray characteristics and Sauter mean diameter was only investigated among the microscopic spray characteristics. There exist six different definitions of spray angle which should be examined. Neat vegetable oil and biodiesel fuels show smaller spray angle than diesel fuel. Biodiesel fuel and vegetable oils and its blend have a longer spray penetration than diesel fuel. However, biodiesel blends with diesel shows the similar spray penetration with diesel fuel. SMDs in the biodiesel spray, vegetable oils and its blends spray are higher than that in the diesel spray.

• Journal of the Korean Society of Food Culture
• /
• v.9 no.4
• /
• pp.335-340
• /
• 1994

The objective of this study was to determine effects of soybean oil(SO), cottonseed oil(CO) and ricebran oil(RO) on stability and flavor of yackwa. This study consisted of yackwa fried in 3 differnet oils, then stored for 0, 3, 6 weeks in normal wrap at room temp. or vaccum package at $4^{\circ}C$. The moisture, oil contents, Hunter color values(L, 'a' and 'b'), % free fatty acid(FFA), thiobarbituric acid(TBA) value and sensory scores for color, flavor and acceptability were analyzed. The foam height of the oil after frying was also determined. Yackwa fried in RO was more red('a'=11.43) than yackwa fried in SO(10.64) or CO(10.51). TBA value of yackwa showed no difference among frying oils. Yackwa fried in SO showed better acceptability than those fried in CO. Yackwa fried in RO showed similar acceptability to yackwa fried in SO. The % FFA and TBA value of yackwa averaged across oil and package showed increasing tendency during 6 weeks storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.4
• /
• pp.654-659
• /
• 1994

To elucidate the relationship between physical and chemical properties of frying vegetable oils, soybean oil and cottonseed oil were heated in air temperatures from $160^{\circ}C\;to\;220^{\circ}C$ for 60 hours. Acid value, carbonyl value, iodine value, viscosity and content of polymer were remarkably changed as higher heating temperature and/or longer heating time. Correlation coefficient of viscosity to acid value was 0.9843 for soybean oil and 0.9819 for cottonseed oil. In case of viscosity and carbonyl value, viscosity also showed good relationship to carbonyl value as 0.9779 for soybean oil and 0.9797 for cottonseed oil. And correlation coefficient of viscosity to iodine value of soybean oil was 0.9852 and cottonseed oil was 0.9948.