• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.287-292
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• 2012

Light effects on temperature dependence of safflower oil oxidation and tocopherol degradation were studied. Safflower oil was oxidized at 20, 40, 60, or $80^{\circ}C$ for 30, 30, 15, and 6 days, respectively, in the dark or under light. Oil oxidation was evaluated with peroxide value (POV) and conjugated dienoic acid (CDA) value, and tocopherols were monitored by HPLC. Safflower oil consisted of palmitic, stearic, oleic, and linoleic acids at 7.3, 2.0, 14.2, and 76.6%, respectively, with tocopherols at 1157.1 mg/kg. Peroxide and CDA values of safflower oil increased while tocopherol contents decreased with the oxidation time and temperature. Light increased and accelerated the oil oxidation and tocopherol degradation. Temperature dependence of the oil oxidation and tocopherol degradation was higher in the dark rather than under light. The results suggest that temperature control could be more essential in the dark rather than under light with regard to the oxidative stability of safflower oil.

• Journal of the Korean Applied Science and Technology
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• v.10 no.2
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• pp.49-56
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• 1993

The effect of frozen storage and cooking methods on lipid oxidation in chicken meat was studied. Chicken meats were stored 0, 30, 60, 90, 120 days at $-18^{\circ}C$ and were evaluated before and after cooking. 1. The crude fat content of chicken meat is the highest thigh meat with skin in microwaving. Fat content was increased duting 30 days of frozen storage, and then after. 2. Peroxide value, acid value and TBA value was increased during the days of storage because lipid autoxidation was processed cooking and during frozen storage time. The peoxide value and acid value were higher compared to sample cooked by other methods. 3. The fluoresence units were increased with frozen storage, and initial levels of fluoresent after processing. 4. The fatty acid composition of chicken meat fats is mainly palmitic acid and oleic acid, and the effect of frozen storage and meats part is not significantly change but fatty acid significantly change according to frying that linoleic acid was increased during frozen time. From all the results obtained in this study it can be conclude that lipid autoxidation of the chicken meat frozen storage at $18^{\circ}C$ was consistantly processed, and breast meat oxidation was increased than thigh meat because chicken breast meat include many polyunsaturated fatty acid. Frying was significantly increased highest than other cooking methods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.2
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• pp.163-167
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• 1990

Antioxidative effects of soybean paste(SP) on the lipid oxidation were studied with the model systems of ground cooked meat(GCM)-SP or ground cooked fish(GCF)-SF and model systems of linoleic acid mixture(LA)-SP powder (SPP) or LA-SP extract fractions during oxida-tion reaction. SP played a role as an antioxidative substance in the system employed especially in GCM-SP and the antioxidative activity was increased with the increase of SP addition in the system of GCF-SP during storage at 6$^{\circ}C$ SPP also exhibited some antioxidative activity during the oxidation reaction of LA. the activity was increased as the concentrations of SPP increased in the range from 0.1% to 0.5% Considerable antioxidative activities have been observed in both water soluble and lipid soluble fractions from SP on LA reaction system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.2
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• pp.148-155
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• 1991

Lipid oxidation and browning during fermentation of domestic Meju and Doenjang were examined in order to elucidate the antioxidative effects of browning products and phenol compounds from Meju and Doenjang. Peroxide values of lipids from Meju were detectable and slightly increased until 3 weeks of fermentation, but started to be decreased after 3 weeks of fermentation and notdetectable after 6 weeks. Peroxides were not detected in Doenjang during the whole fermentation, but started to be decreased after 3 weeks of period of 22 weeks fermentation. Carbonyl value were increased during the whole period of Meju fermentation, but started to be decreased at the early stage of Doenjang fermentation. Hydrophilic fraction of browning products from Meju was much higher than lipophilic fraction and the former fraction was dramatically increased at the early stage of the fermentation. But the both fractions maintained high values during Doenjang fermentation. Hydrophilic browning products and phenol and phenol compound in Meju showed strong antioxidative against linoleic acid.

• BMB Reports
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• v.40 no.1
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• pp.100-106
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• 2007

The wound-inducible lipoxygenase obtained from maize is one of the nontraditional lipoxygenases that possess dual positional specificity. In this paper, we provide our results on the determination and comparison of the kinetic constants of the maize lipoxygenase, with or without detergents in the steady state, and characterization of the dependence of the kinetic lag phase or initial burst, on pH, substrate, and detergent in the pre-steady state of the lipoxygenase reaction. The oxidation of linoleic acid showed a typical lag phase in the pre-steady state of the lipoxygenase reaction at pH 7.5 in the presence of 0.25% Tween-20 detergent. The reciprocal correlation between the induction period and the enzyme level indicated that this lag phenomenon was attributable to the slow oxidative activation of Fe (II) to Fe (III) at the active site of the enzyme as observed in other lipoxygenase reactions. Contrary to the lagging phenomenon observed at pH 7.5 in the presence of Tween-20, a unique initial burst was observed at pH 6.2 in the absence of detergents. To our knowledge, the initial burst in the oxidation of linoleic acid at pH 6.2 is the first observation in the lipoxygenase reaction. Kinetic constants (Km and kcat values) were largely dependent on the presence of detergent. An inverse correlation of the initial burst period with enzyme levels and interpretations on kinetic constants suggested that the observed initial burst in the oxidation of linoleic acid could be due to the availability of free fatty acids as substrates for binding with the lipoxygenase enzyme.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.478-482
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• 1995

The changes of the lipid composition and of the contents of carotenoid and tocopherol in wheat germ were studied during the storage at $30^{\circ}C$. The contents of triglyceride and free fatty acid were changed from 66% and 7% to 49% and 24% respectively after 30 days. The predominant free fatty acids were lauric acid (29%), palmitic acid (21%) and linoleic acid (20%), however, linoleic acid increased to 30%, lauric acid reduced to 21% after storage of 30 days. The carotenoids in the wheat germ were ${\beta}-carotene,\;{\alpha}-carotene$, lutein and taraxanthin, and the contents of these were 306, 59, 383 and 356 ng/g wheat germ, respectively. Their contents, however, were reduced to 36, 4, 203 and 149 ng respectively after 20 storage days. Especially, degradation rate of ${\beta}-carotene$ was 22.5 ng/day. The tocopherol isomers in wheat germ were ${\alpha}-,\;{\beta}-\;and\;{\gamma}-tocopherol$, and they reduced from $55,\;48\;and\;38\;{\mu}g/g$ wheat germ to 35, 32 and $32\;{\mu}g$ respectively after 20 storage days. The ${\alpha}-tocopherol$ was degraded by $1.26\;{\mu}g/day$ at this storage condition.

• Journal of the Korean Applied Science and Technology
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• v.2 no.2
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• pp.39-46
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• 1985

The study was carried out to investigate interrelationships among the acid, peroxide, iodine, thiobarbituric acid values, and changes of fatty acid compositions of some vegetable oils added to soybean milk. A storage temperature of $100^{\circ}C$ was used for the oxidation of the oils, and to determine of variation of the chemical properties and changes of the fatty acid composition, all the samples were carried out in every 8 hours for 40 hours. The changes in fatty acid compositions of the vegetable oils were measured by high performance liquid chromatography. The results obtained were as follow; 1. The acid values of the fresh soybean, corn, and palm oils added to the soybean milk were 0.05, 0.12, and 0.06, whereas those of the oils stored for 40 hours were 0.08, 0.18, and 0.09, respectively. 2. The peroxide values of the fresh soybean, corn, and palm oils added to the soybean milk were 0.3, 1.0, and 0.3, whereas those of the oils stored for 40 hours were 1.1, 1.1, and 0.9, respectively. 3. The iodine values of the fresh soybean, corn, and palm oils added to the soybean milk were 132.7, 124.1, and 57.0, whereas those of the oils stored for 40 hours were 127.3 108.3, and 52.0, respectively. 4. The thiobarbituric acid values of fresh soybean, corn, and palm oils added to the soybean milk were 0.18, 0.05, and 0.02, whereas those of the oils stored for 40 hours were 0.25, 0.19, and 0.07, respectively. 5. The percent content of the major fatty acids of the soybean, corn, and palm oils freshly added to the soybean milk were 2.3%,2.5%,and 25.2%for palmitic acid, 3.2%,3.2%,and 4.8%for stearic acid, 39.7%, 40.7%, and 59.3% for oleic acid, 49.9%, 53.0%, and 10.5% for linoleic acid, and 4.7%, 0.4%, and 0.7% for linolenic acid, respectively. Those of the oils stored for 40 hours were 2.9%, 4,5%, and 36.7% for palmitic acid, 8.5%, 6.8%, and 7.0% for stearic acid, 37.8%, 38.8%, and 49.2% for oleic acid, 46.2%, 49.5%, and 5.8% for linoleic acid, and 4.2%, 0.1%, and 0.1% for linolenic acid, respectively. The fatty acid compositions changed significantly: the amounts of the unsaturated fatty acid decreased considerably. The rsults of the present study demonstrated greater stability of the palm oil as compared with the stability of soybean oil and corn oil added to the soybean milk.

• Journal of Food Hygiene and Safety
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• v.20 no.2
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• pp.89-97
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• 2005

The influence of different storage temperature and packaging methods on the flying cultured eel bone were investigated. The acid values, peroxide values and fatty acid composition were measured during storage 20$^{\circ}C\;and\;40^{\circ}C$ for 60 days. The lipid oxidation was rapidly progressed with the increased temperature. The addition of oxygen absorber remarkably repressed lipid oxidation during storage of the living cultured eel bone at $20^{\circ}C\;and\;40^{\circ}C$, followed by $N_{2},\;BHA,\;\alpha$-tocopherol and control. The monounsaturated fatty acid content was the highest in the frying cultured eel bone, followed by saturated fatty acid and polyunsaturated fatty acid. The major fatty acids were oleic acid, palmitic acid and linoleic acid. The saturated fatty acids increased with the rise of storage temperature and prolonging the storage period, while monounsaturated fatty acid and polyunsaturated fatty acid were decreased. The changes of fatty acid composition were the lowest in sample by packing with oxygen absorber, followed by packing $N_{2},\;BHA,\;\alpha$-tocopherol and control. from the result of sensory evaluation, sample by packing with oxygen absorber were rated as higher quality than the others.

• Food Science and Preservation
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• v.7 no.3
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• pp.331-336
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• 2000

The phenolic compounds of Korean sweet potatoes, Mokpo 18 and Yulmi, were extracted by using 70%-methanol and the extracts(ME) were fractionated and obtained three fractions such as free phenolic acid(FPAF), soluble phenolic acid ester(SPAF) and insoluble bound phenolic acid(BPAF) fractions. The antioxidative activities(AA) was represented as the peroxide values(POVs). The POVs were calculated by measuring the oxidation of linoleic acid and lard emulsions at $60^{\circ}C$. AA of FPAF has shown the most effective. AA of FPAF were more effective than those of ME in both Yulmi and Mokpo 18. AA of the ME of Mokpo 18 were more effective than those of Yulmi, however, those of FPAF in Ulmi were more effective than in Mokpo 18. The POVs of ME and FPAF of the peel part in both sweet potatoes were more effective than those of peeled part. The qualitative and quantitative analysis of the phenolic compounds in both sweet-potatoes were performed by using high performance liquid chromatography(HPLC) and the major phenolic compounds were identified as chlorogenic acid and caffeic acid. The contents of caffeic acid were 0.684mg/g in the peel part and 0.028mg/g in the peeled part of Yulmi and 0.472mg/g in the peel part and 0.046mg/g in the peeled part of Mokpo 18 and those of chlorogenic acid was 0.674mg/g, 0.926mg/g, and 0.012mg/g, respectively. In comparative test of antioxidative activities between a standard chlorogenic acid and caffeic acid, AA of caffeic acid were more effective than those of chlorogenic acid.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1999.06a
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• pp.200-200
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• 1999