• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.435-439
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• 2008

Due to the fact that tocopherols and tocotrienols have antioxidant and anticancer properties, the commercial utilization of unsaponifiable fractions in rice bran is increasing. These nutraceutical compounds, however, are fairly unstable and readily break down when exposed to oxygen or lighting conditions. To compare the relative sensitivity of vit E isomers to heat and oxygen, concentrated unsaponifiable fractions extracted from crude rice bran oil were exposed to various temperature, oxygen (nitrogen-balanced), and bathing solvent conditions and resultant concentration changes in ${\alpha}$- and ${\gamma}$-tocopherols (T) and tocotrienols (T3) were evaluated. Each isomer exhibited different heat stability. Among them, ${\alpha}$-T3 degraded more rapidly compared to other vit E isomers while ${\alpha}$-T was the most stable isomer. Oxygen level also showed significant impact on each isomer's stability where severe reductions of ${\gamma}$-T (by 20%) and ${\gamma}$-T3 (by 29%) were observed under 2% oxygen conditions, while under 0% oxygen conditions no degradation could be observed even after exposure to $95^{\circ}C$ for 4 hours. When various blending solvents were mixed with concentrated unsaponifiable fractions, organic solvents such as isooctane and hexane were more effective in maintaining the stability of ${\gamma}$- T3 compared to edible oils, among which com oil was more efficient than soybean and rice bran oils.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.255-260
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• 2002

Yukwa is a popular Korean traditional fried rice snack. The high fat content and porous structure of Yukwa cause it to rapidly become rancid, presenting difficult challenges for commercial distribution. In this study, an-tioxidant activities of green tea extracts (GTE) were evaluated in Yukwa fried in soybean oil (SBO), rice bran oil (RBO) and winterized rice bran oil (WRBO) during storage at 4$0^{\circ}C$ for 12 weeks. Lipid oxidation of Yukwa was determined by acid value (AV), peroxide value (POV), p-anisidine value(AnV), totox value and sensory evaluation. The addition of GTE to the oils reduced the increases in AV, POV, AnV, and totox. Totox increased most vapidly in Yukwa fried in SBO, fellowed by RBO>WRBO>SBO+200 ppm GTE>RBO+200 ppm GTE > WRBO + 200 ppm GTE (p<0.05). Sensory evaluation revealed that the addition of 200 ppm GTE delays rancidity in Yukwa by 7~8 weeks; providing compelling evidence that GTE is an effective antioxidant for Yukwa.

• Journal of Food Hygiene and Safety
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• v.8 no.3
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• pp.151-155
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• 1993

Since there have been no method which can applicable to the screening of commercial sesame oil adulterated with other vegetable oils, the present investigation was carried out particularily focusing on the the pattern of IN absorption of sesame oil and other vegetable oils. For this, a variety of oil samples prepared by the conventional method from sesame seeds, perilla seeds, com, soybean, and rice bran were analyzed by IN spectrophotometer. IN spectra of sesame oil and oil of unheated sesame seeds showed absorption peaks at 215, 230 and 290 nm. While UV spectra of com oil, perilla oil and soybean oil all showed absorption peaks at 215, 230 and 280 nm, that of rice bran oill showed peaks at 215, 290 320 nm. When sesame oil was mixed with com oil, perilla oil or soybean oil, respectively, from which the absorbance of peaks at 290 nm were lower than pure sesame oil. The peak at 320 nm which was typical absorption peak of rice bran oil was still observed in the spectnun of mixture of sesame oil with rice bran oil.

• Journal of environmental and Sanitary engineering
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• v.4 no.1 s.6
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• pp.29-36
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• 1989

The purpose of this investigation was performed for chemical values related to rancidity of fat and oils extracted from deep-frying food in Seoul. The samples were collected according to kinds of fat and oils, sampling sites and food stuffs for frying. The results were as follows 1. The most used frying oils were rice bran oil $(37.0\%)$ and shortening $(29.6\%)$, followed by rapeseed oil $(14.8\%)$. 2. The chemical values related to rancidity of fat and oils extracted from deep-frying foods were the next on average. Acid value-1.42, peoxide value-39.82, dinitrophenyl hydrazine value-16.73 thiobarbituric acid value-0.263. However the highest value among oils was showed in rice bran oil and the lowest value was shortening. 3. For the classification of sampling sites, acid value and peroxide value of samples of the markets were found higher than them of environs of school and roadside, and the differences between them were significant (P> 0.01), while dinitrophenyl hydrazine value and thiobar bituric acid value were not showed the significant differences. 4. For the classification of foodstuffs for frying, there were not recognized significant differences among all kinds of them.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.359-368
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• 1996

The performance and exhaust emissions of a diesel engine using light oil, heated, rice-bran oil , heated rice-bran oil treated with ultrasonic wave, used frying oil, use frying oil treated with ultrasonic wave, used frying oil, used frying oil treated with ultrasonic wave, methyl esters of rice-bran oil and used frying oil have been compared. All the fuels performed satisfactorily in a precombustion chamber-type diesel engine without injection pump recalibration or any engine modification at the range of engine speed from 1600 to 2800 rpm at its full load during a sort period , with the rice-bran oil and rice-bran oil treated with ultrasonic wave requiring somewhat preheating when ambient temperature was below 15$^{\circ}C$. General performance and emission characteristics of light oil and bio-oils were comparable , with the bio-oil based fuels giving very low SO$_2$ and lower smoke readings.

• Journal of Nutrition and Health
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• v.26 no.5
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• pp.524-531
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• 1993

In this experiment, we investigated the changes of erythrocyte feature and Ca concentration in rat fed the diet containing different common oils in Korea for different feeding periods(4 weeks or 12 weeks), using Korea sesame oil, perilla oil, rice bran oil and mixed oil. W-3/w-6 ratio of each group was 0.001, 1.44, 0.03 and 0.112, respectively. P/S ratio of each group was 9.64, 10.49, 5.58 and 1.68, respectively. Perilla oil(w-3 rich) increased w-3/w-6 ratio of erythrocyte membrane, decreased the amount of trapped Ca and inhibited the decrease of cell volume. These results indicate that in maybe increase erythroyte fluidity and deformability, and affect erythrocyte function. In conclusion, w-3 rich perilla oil affects erythrocyte feature.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.754-762
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• 1998

Exhaust emissions in diesel engine are affected by fuel properties but the reason for this is not clear. Especially the recent strong interest in using low-grade fuel demands extensibe investigation in order to clarify the exhaust emissions. Bio-Diesel oil has a great possibility to solve the pollution problem caused by the exhaust gas from diesel engine vehicles. The use of bio-oils in diesel engines has received considerable atten-tion to the forseeable depletion of world oil supplies. So bio-diesel oil has been attracted with attentions for alternative and clean energy source. The purpose of this paper is to evaluate the fea-sibility of the rice-bran oil for alternative fuel in a diesel engine with rgard to exhaust emis-sions.

• KSBB Journal
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• v.10 no.4
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• pp.449-454
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• 1995

The effects of metathesis for concentrating the tocopherols from soybean and rice-bran scum oils were studied by using the batch reactor under helium atmosphere. The contents of tocopherols in the scum oils decreased consticuously when heated under air atmosphere or when kept in hexane solution above 5 days even at room temperature. The sterols in the scum oils were removed by the mixed solvent method. Metathesis of the sterol-removed scum oils in hexane was performed over Re2O7/Al2O3 and WO3/Al2O3 catalysts, and the concentrate was obtained by distillation in vacuum at $190^{\circ}C$. The effect of metathesis was evaluated as relative ratio of ${\alpha}$-tocopherol in the concentrate to that in scum oil. The maximum ratio for both scum oils was obtained on 12.8%(w/w)$Re_2O_7/Al2O_3$ catalyst which formed effectively the active sites for metathesis by the reaction between the added tetramethyltin and $Re_2O_7$ on the surface of the catalyst. The optimum amount of the catalyst was 0.5g pre l0g scum oil, and the optimum reaction temperature was $25^{\circ}C$ for both scum oils. The metathesis was more effective in rice-bran scum oil than in soybean scum oil. These facts indicated that the tocopherols in the scum oils can be highly concentrated by applying metathesis.

• Journal of Nutrition and Health
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• v.26 no.5
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• pp.513-523
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• 1993

In this experiment, we investigated the hypolipidemic and antithrombotic effects of rats fed diets with different common oils in Korea for different feeding periods(4 weeks or 12 weeks), using Korean sesame oil, perilla oil, rice bran oil and mixed oil. W-3/w-6 ratio of each group was 0.001, 1.44, 0.03 and 0.112, respectively. P/S ratio of each group was 9.64, 10.49, 5.58 and 1.68, respectively. The result were as follows: 1) According to the age, body fat accumulation was increased. 2) Perilla oil(w-3 rich) decreased total lipid, triglyceride and total cholesterol, and increased HDL/total cholesterol ratio. 3) With regard to the compositono of platelet fatty acids, Perilla oil increased w-3/w-6 ratio of the platelet. Perilla oil lengthened bleeding time and decreased MDA(MalonDAdehyde) formation which determined in place of Thromboxane A2(TXA2) in platelet. This result can suggest that linoleic acid of perrilla oil seem to supress the conversion of linoleic acid to arachidonic acid(AA 20:4, w-6) and eicosapentaenoic acid(EPA, 20:5, w-3) trannnsformed from linolenic acid to suppress the conversion of arachidonic acid to TXA2. Since TXA2 is platelet-aggregating and vasoconstricting agent, the reduction of TXA2 tgeneration by platelet with increased linolenic acid intakes shows prologed bleeding time. In conclusion, w-3 rich perilla oil has strong hypolipidemic and antithrombotic effects by changing fatty acid profiles of the platelet.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.77-81
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• 1998

Rice germ oils were extracted from common and dried rice germ $(80^{\circ}C,\;6\;hr)$, and their oxidative stabilities were evaluated by measuring acid value, peroxide value and fatty acid composition during storage at $40^{\circ}C\;and\;60^{\circ}C$. The acid values of all lipids were slightly changed during storage, but peroxide values (POV) were greatly dependent on storage temperature. The POVs of the dried germ oil and the refined rice bran oil were 146.2 meq/kg and 15.1 meq/kg, respectively after 31 days storage at $40^{\circ}C$. However after 24 days of storage at $60^{\circ}C$, the POVs of the dried germ oil and the refined rice bran oil were 151.7 meq/kg oil and 219.6 meq/kg oil, respectively. Major fatty acids were linoleic (39.8%) and oleic acid (34.7%) in rice germ oil, and oleic (40.1%) and linoleic acid (38.1%) in rice bran oil. The major fatty acid compositions were not greatly influenced by drying and storage temperature but linoleic acid decreased about half during storage.