Earticle

연구목적: 옥수수유는 반건성유로서 불건성유보다 이중결합의 수가 많고 산소와 결합하기 쉬우므로 자 연발화의 조건이 충족되면 적은 양으로도 가연성 물질에 흡착될 경우에는 자연발화가 쉽게 발생된다. 또한 최근 자연발화의 원인 중 산화열에 의해 기름이 묻은 헝겊 등에 의한 사고가 늘어나고 있다. 그러므 로 65℃에서 타올의 매수와 옥수수유의 양에 따른 자연발화의 특성을 파악하고자 한다. 연구방법: 실험 온도를 65℃로 설정한 후 타올 한 장당 25ml, 50ml, 75ml에 해당하는 옥수수유를 분사시킨 후 시료의 중 심 온도가 설정된 온도보다 상승하고, 타올이 연소로 인해 탈 경우에는 발화로 판정하였으며, 시료의 중 심 온도가 설정된 온도와 유사할 경우에는 비발화로 판정하였다. 연구결과: 옥수수유를 타올 한 장 당 25ml씩 골고루 분포시킨 후 실험을 한 결과 타올이 5장 일 때는 비발화되었으며, 타올이 10장, 15장일 때 는 발화되었다. 또한 옥수수유를 타올 한 장 당 50ml, 75ml씩 사용하여 실험한 결과 타올이 5장, 10장, 15 장일 때 자연발화가 발생되었다. 결론: 옥수수유가 적은 양으로도 자연발화의 조건을 충족하면 화재가 발생할 수 있다.

Purpose: As corn oil is semi-drying oil, it has more double bonds than non-drying oil and is easier to combine with oxygen. In addition, among the causes of spontaneous ignition, accidents caused by oilsoaked cloths due to oxidative heat are gradually increasing. Therefore, the purpose of this study is to understand the characteristics of spontaneous combustion according to the number of towels and the amount of corn oil at 65℃. Method: After setting the test temperature to 65℃, 25ml, 50ml, 75ml of corn oil per towel was sprayed. The central temperature of the sample rises above the set temperature. It was determined, and when the central temperature of the sample became similar to the set temperature, it was determined as non-igniting. Result: After evenly distributing 25ml of corn oil per towel, as a result of the experiment, 5 towels did not ignite, and 10 and 15 towels ignited. Also, as a result of an experiment using 50ml and 75ml of corn oil per towel, spontaneous ignition occurred when the number of towels was 5, 10, or 15 sheets. Conclusion: Even a small amount can cause a fire if the conditions for spontaneous ignition are met.

The microbial biosurfactants can be substituted to the chemical detergents in some industrial processes. In this study we developed a biotechnological processes for the biosurfactants with microorganisms. The biosurfactants have a lot of advantages in comparision with the chemical surfactants. They are proenvironmental even during and after industrial use. But there are not so many kinds of biosurfactants. The production cost and the end price is much higher than the chemical surfactants. But nowdays there are many kinds of microorganisms, which can produce the surfactants in large quantity and fast. We tried to develop a production process for the large scale with some microorganisms. At first Candida bombicola KCTC 7145, Sphingomonas chungbukensis KCTC 2955 and Sphingomonas yanoikuyae KCTC 2818 are cultivated and studied. For the large scale production process we used molasses as a complex medium and tried to optimize the process. Molasses contains 17 to 25% of water, 45 to 50% of sugar and 25% of carbohydrate, it can be fully used as a substrate. The microorganisms have been cultivated in the diluted media with molasses 2, 5, 8 and 10%, respectively, The optimal conditions for the cultivation and the production process have been studied. For the study the optical density, glucose concentration and the surface tension were measured. Candida bombicola KCTC 7145 and the 5% molasses media was selected as an optimal condition for the production process of a biosurfactant. During cultivation of Candida bombicola KCTC 7145 in the 5% molasses medium kerosene and corn oil were added for promoting the biosurfactants.

5% corn oil과 17 mM Brij 700으로 제조한 corn oil-in-water emulsion(O/W)의 droplet의 크기는 첨가되는 phenol의 양이 많아질수록 지방구가 다소 커지는 경향을 보였으며, continuous phase의 surfactant 양은 대조구에 비해 다소 낮아졌다. O/W에 녹차로부터 분리한 phenol류를 100-200 ppm의 농도로 첨가하고 30일간 저장하며 hydroperoxide의 생성량을 측정한 결과 대조구에 비해 낮은 hydroperoxide 함량을 보여 유도기간이 길어지는 것으로 나타났으며, phenol 종류별 hydroperoxide 생성억제 효과는 BHT > procyanidin B3-3-O-gallate>(+)-gallocatechin>(+)-catechin의 순서로 나타났다. 지방 산화의 결과 발생하는 aldehyde의 함량을 측정함으로서 산화정도를 측정하기 위하여 headspace hexanal 양을 측정한 결과, 대조구는 15일까지 hexanal이 검출되지 않았으나 phenol 첨가구는 20-30일로 headspace aldehyde의 불검출기간이 길어졌으며, 농도가 증가할수록 낮은 함량을 나타내었다. Phenol 종류별 headspacealdehyde 생성 억제 효과는 BHT > procyanidin B3-3-O-gallate > (+)-gallocatechin >(+)-catechin의 순서로 나타났다.

Effect of polyphenolic compounds from green tea leaves and surfactant micelles on lipid oxidation in corn oil-in-water emulsion (O/W) wag determined. Concentrations of polyphenolic compound and surfactant in continuous phase of O/W were measured. Particle size of O/W with 17 mM Brij 700 and 5% corn oil increased with increasing concentration of polyphenolic compound (100-200 ppm). Concentration of surfactant in the continuous phase was lower than that of control. Lipid oxidation rates, as determined by the formation of lipid hydroperoxides and headspace hexanal, in O/W emulsions containing polyphenolic compounds decreased with increasing concentration of polyphenolic compounds (100-200 ppm). Inhibition of hydroperoxide and headspace hexanal produced via lipid oxidation by polyphenolic compounds in O/W was BHT>procyanidin B3-3-O-gallate>(+)-gallocatechin >(+)-catechin.

The purpose of this study was to prepare stable water-in-corn oil (W/O) emulsion droplets coated by polyglycerolpolyricinoleate (PGPR). W/O emulsions (20 wt% aqueous phase, 80 wt% oil phase containing 8 wt% PGPR) were producedby high pressure homogenization (Emulsions 1), however, appreciable amount of relatively large water droplets (d>10µm)were found. To facilitate droplet disruption, viscosity of each phase was adjusted: (i) increased the viscosity of aqueous phaseby adding 0.1wt% xanthan (Emulsions 2); (ii) decreased the viscosity of oil phase and aqueous phase by heating themseparately at 50oC for 1hr immediately before emulsification (Emulsions 3). Homogenizing at the elevated temperatureclearly led to a smaller water droplet size, whereas xanthan neither improved nor adversely affected on the microstructures ofthe emulsions. In addition, the Emulsions 3 had good stability to droplet aggregation under shearing stress, thermal processing,and long term storage.

회분식 반응기(stirred-tank batch reactor)를 사용한 DAG, MAG 함유 기능성유지를 비용매계(solvent-free system) 조건에서 효소적 반응을 이용하여 합성하였다. 48시간 동안 합성된 지질을 HPLC를 사용한 TAG, 1,3-DAG, 1,2-DAG 및 MAG 함량 분석결과 각각 45.05, 16.27, 23.05 및 14.98%로 분석되었으며 체중개선 기능성 유지의 지방산 조성 분석결과 palmitic, palmitoleic, stearic, oleic, linoleic 및 linolenic acid가 13.21, 0.15, 2.02, 34.36, 49.12 및 1.14 mol%로 분석되었다. 합성된 지질의 α, Γ 및 δ-tocopherol 함량을 분석한 결과는 각각 0.014, 0.029 및 0.010%로 분석되었으며 총 tocopherol 함량은 0.053%로 나타났다. 또한 재구성된 지질을 사용하여 산가, 비누화가, 요오드가를 측정하였으며 융점 및 결정화점을 살펴보고 이를 통하여 옥수수유로 유래된 DAG, MAG를 함유한 체중개선 기능성 유지의 이화학적, 물리적 특징을 규명하였다. 체중개선 기능성 유지의 산화 안정성 실험을 시행한 결과 체중개선 기능성 유지가 원료유인 옥수수유보다 높은 과산화물가와 p-anisidine가를 보였으며 각기 달리 혼합한 rosemary추출물(100, 200 및 300ppm)이 체중개선 기능성 유지와 옥수수유의 산화를 감소 시켰다.

Mono-and diacylglycerol-enriched oil was produced from corn oil through enzymatic glycerolysis using 1,3-specific immobilized lipase in solvent-free system and stirred-tank batch reactor. HPLC analysis revealed enriched oil was respectively composed of: 45.05, 16.27, 23.05, and 14.98% triacylglycerol, 1,3-diacylglycerol, 1,2-diacylglycerol, and monoacylglycerol, 13.21, 0.15, 2.02, 34.36, 49.12, and 1.14 mol% palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids, and 0.014, 0.029, 0.010 and 0.053% α, Γ, δ-, and total tocopherols. Physiochemical and melting properties of enriched oil were evaluated. Oxidative stability study revealed enriched oil showed higher peroxide and p-anisidine values than corn oil. Rosemary extracts (100 to 300 ppm) reduce oxidation.

Lipozyme RM IM 효소적 촉매를 사용한 glycerolysis에 의한 옥수수유로부터 1,3-DAG(Y1), 1,2-DAG(Y2), 총 DAG(Y3), MAG (Y4), 및 총 DAG + MAG 의 합성 양(Y5)의 생성 최적화를 반응 표면분석을 이용하여 모니터링 하였으며 반응온도(35-75℃, X1), 반응시간(1-11시간, X2) 및 hexane 의 혼합 양(0-2mL, X3)을 변수로 한 중심합성계획으로 최적화 실험하였다. 1,3-DAG는 반응온도(44.92℃), 반응시간(10.24시간) 및 hexane 첨가량(1.16mL) 조건에서 20.43 area%로 최대값을 나타내었으며 1,2-DAG는 56.32℃, 6.95시간 및 1.04mL 조건에서 26.78 area% 로 최대값을 예측할 수 있었다. 총 DAC는 53.82℃, 8.03시간 및 1.08mL 실험 조건에서 45.09 area% 최대값을 보였다. 또한 MAG 생산 최적조건은 64.14℃, 7.00시간 및 0.13mL에서 최대값 9.57 area%로 예측되었으며 총 DAG+MAG 생산 최적조건은 54.07℃, 7.98시간, 1.02mL이었으며 이때 예측된 값은 53.54 area%이었다.

Response surface methodology was used to optimize production conditions of monoacylglycerol (MAG) and diacylglycerols (DAG) from corn oil by enzymic glycerolysis. Contents of 1,3-DAG (Y1), 1,2-DAG (Y2), total DAG (Y3), MAG (Y4), and total DAG+MAG (Y5) were obtained. Conditions were optimized using central composite design with incubation temperature (35-75℃, X1), incubation time (1-11 hr, X2), and amount of hexane added (0-2 mL, X3) as three variables. Content of 1,3-DAG was maximized by 20.43 area% at incubation temperature of 44.92℃, incubation time of 10.24 hr, and hexane content of 1.16 mL, whereas that of 1,2-DAG (26.78 area%) was maximized at 56.32℃, 6.95 hr, and 1.04 mL, respectively. Predicted maximum total DAG content was 45.09 area% at 53.82℃, 8.03 hr, and 1.08 mL, while production conditions of MAG (9.57 arae%) were 64.14℃, 7.00 hr, and 0.13 mL. At variables of 54.07℃, 7.98 hr, and 1.02 mL, maximum content of total DAG+MAG predicted by RSM was 53.54 area%.

This study was conducted to compare the effects of n-6 linoleic acid and n-3 linolenic acid on lipid peroxidation and the activities of enzymes defending against oxidation, which are involved in the tumor promotion, and histolOgical changes of hepatocarcinogen treated rat liver. In this study, weanling male Sprague-Dawley rats were fed one of three diets, containing 15% (w/w) of beef fat (BF), com oil (CO) or perilla oil (PO), for 11 weeks. During the 3rd week, experimental groups were injected with 2-AAF (50 mg/kg of BW) intraperitoneally 3 times. Findings show that the com oil diet group has greater liver MDA content than the beef fat and perilla oil diet groups. Also, it is observed that the perilla oil diet group has lower MDA content than beef fat and com oil diet groups, even though perilla oil is more desaturated than beef fat and com oil. In terms of activity, mixed-function oxidase activity is not Significantly affected by the different dietary fats and 2-AAF treatment. GSH-peroxidase, GSH-reductase and GSH-Stransferase activities are significantly higher in the CO+AAF group than those of the other groups. GST and GSH-Px are activated by 2-AAF treatment in the com oil diet group only. The hepatocytes of the BF+AAF group were the most severely degenerated, the second was the CO+AAF group and the least was the PO+AAF group. It was also found that dietary com oil increased lipid peroxidation and activated defense enzymes against oxidation in liver, but dietary perilla oil did not, or supressed defense enzymes. Therefore it is concluded that dietary n-3 linolenic acid in perilla oil inhibits lipid peroxidation and carcinoenesis in rat liver following 2-AAF treatment.

The study carried out to clarify the effects of lard and corn oil on serum total cholesterol content and liver thiobarbituric acid (TBA) value in ethanol (Et-OH) fed mice. Results obtained from the present study were a follows: 1. serum total cholesterol content was considerably increased by 25% Et-OH administration in mice. In case of 25% Et-OH plus Lard group and Lard group both group were also increased significantly to compare with normal value of mice but 25% Et-OH plus lard group was shown very higher value rather than that of Lard group and Lard group was found similar tendency to compare with the 25% Et-OH plus saline group except to after the 1 day. 2. serum total cholestrol content of 25% Et-OH plus Corn oil group and corn oil group were also increased significantly to compare with normal value, but the 25% Et-Oh plus Corn oil group slightly higher level than that of Corn oil group except to after the 3 days. 3. Lard group was also very similar tendency to compare with the corn oil group except to the 3 days. 4. liver TBA value was increased by 25% Et-OH fed mice. 25% Et-OH plus Lard group and Lard group were also increased significantly to compare with liver TBA value in normal mice, but 25% Et-OH plus Lard group was found higher value rather than that of lard group and 25% Et-OH group (Control). Lard group was similar to that of Control group except to after the 1 day. And 25% Et-OH plus Corn oil group was considerably increased rather than that of Control group, and liver TBA value of the above group was similar to that of 25% Et-OH plus Lard group except to after the 3 days. Corn oil group was shown lower value than that of lard group, but it was no significant.

It has been reported that dietary polyunsaturated fats (PUFA) increase liver injury in response to ethanol feeding. We tested the hypothesis that diets rich in linoleic acid (18:2n-6) would affect acute liver injury after acetaminophen injection and that protein restriction might exacerbate the liver injury. We examined effects of feeding diets with either 15% (wt/wt) corn oil or 14% beef tallow and 1% corn oil for six weeks with either 6 or 20 g/100 g protein on acute hepatotoxicity. After the feeding period, liver injury was induced by injecting either with 600 mg/kg body weight acetaminophen suspended in gum arabic-based vehicle, or with vehicle alone during fasting status. Samples of liver and plasma were taken for analyses of hepatic glutathione (GSH) levels and liver-specific enzymes [(Glutamate-pyruvate transaminase (GPT) and glutamate-oxaloacetate transaminase (GOT)], respectively. Whereas GSH level was significantly lower in only group fed 15% corn oil with 6 g/100 g protein among acetaminophen-treated groups, activities of GPT and GOT were significantly elevated in all groups except the one fed beef tallow with 20 g/100 g protein, suggesting low protein might exacerbate drug-induced hepatotoxicity. The feeding regimens changed the ratio of 18:2n-6 to oleic acid (18:1n-9) in total liver lipids approximately five-fold, and produced modest changes in arachidonic acid (20:4n-6). We conclude that diets with high 18:2n-6 promote acetaminophen-induced liver injury compared to diets with more saturated fatty acids (SFA). In addition, protein restriction appeared to exacerbate the liver injury.

A 12-w feeding trial was conducted with 600 38-wk-old layers to evaluate the nutritive value of high oil corn(HOC) in layer diets. For the control, a commercial corn-soybean meal basal diet was used. An iso-calorie diet(HOC-ISO) was prepared replacing corn with HOC in the control diet. In addition a third diet was prepared by simply replacing corn with HOC on 1:1 basis to give a high energy diet(HOC-1:1). There were 5 replicates per treatment, and 40 birds per replicate. Birds were housed in an open-sided layer house equipped with wire cages. Feed and water were provided ad libitum, and 17L:7D lighting program was adopted. No significant difference (P>0.05) was found among dietary treatments in laying performance. Also physical qualities of eggs were not significantly affected by the feeding of HOC. Although not significant, HOC-ISO tended to improve the laying rate during the summer. The HOC feeding significantly increased the polyunsaturated fatty acids contents in egg yolk, especially the linoleic acid The AME contents of Chinese yellow corn, U.S. corn, and HOC were 3177, 3158 and 3387 kcal/kg respectively.

5% corn oil과 17 mM Brji 700으로 제조한 oil-in-water emulsion(O/W)에서 과량의 잉여 surfactant가 phenol이 첨가된 O/W의 산화에 미치는 영향을 알아보기 위하여 Brji 700을 $0{\sim}2%$의 농도로 O/W에 첨가한 경우, 첨가된 surfactant의 양이 증가할수록 droplet의 particle size는 커지는 경향을 나타내었다. 또한 continuous phase의 surfactant 농도도 높아지며 phenol 함량도 상대적으로 높아지는 것을 알 수 있었다. Phenol류가 100 ppm의 농도로 첨가된 O/W에 과량의 surfactant$(0{\sim}2%)$를 첨가하고 30일간 저장 기간별 hydroperoxide의 생성량을 측정한 결과, 대조구에 비해 낮은 hydroperoxide 함량을 보여 surfactant를 첨가하지 않은 실험구와 유사한 경향을 보였으나, hydroperoxide 함량은 surfactant를 추가하지 않은 실험구 보다 더 낮은 값을 나타내었다. 또한 phenol 종류 및 surfactant 농도별 hydroperoxide 생성억제 효과와 headspace aldehyde 생성 억제 효과는 BHT>procyanidin B3-3-O-gallate>(+)-gallocatechin>(+)-catechin 및 2%>1%>0% surfactant 첨가의 순서로 나타났다. 이러한 결과는 phenol성 물질과 과량의 surfactant micelle에 의해 emulsion으로부터 continuous phase로 hydroperoxide의 physical location 변화가 발생하는 것을 나타낸다.

The purpose of this research was to determine the effect of phenol compounds from green tea leaves and surfactant micelles on lipid oxidation in com oil-in-water emulsion (O/W). The concentration of phenol and surfactant in continuous phase of the O/W with exceed Brij 700 and phenol compounds was measured. The particle size of O/W with phenol (100 ppm) increased with increasing added exceed surfactant $(0{\sim}2.0%)$ and the concentration of surfactant and phenols in the continuous phase higher than these of control. Lipid oxidation rates, as determined by the formation of lipid hydroperoxides and headspace hexanal, in the O/W emulsions containing phenol compounds (100 ppm) and exceed surfactant $(0{\sim}2.0%)$ decreased with increasing concentration of exceed surfactant. The ability of the phenol compounds and exceed surfactant to inhibit hydroperoxide and headspace hexanal producing as lipid oxidation in O/W was BHT>procyanidin B3-3-O-gallate> (+)-gallocatechin > (+)-catechin and 2% > 1 % > 0% of exceed surfactant. These results indicate that phenol compounds and exceed surfactant could alter the physical location of hydroperoxide in O/W.

Structured lipids (SLs) are defined as triacylglycerols to change the fatty acid composition in the glycerol backbone and lipases are known as a powerful tool for the syntheses of SLs. Structured lipid from corn oil, capric acid, and conjugated linoleic acid (CLA) by transesterification reaction and using several amounts of immobilized lipase RM IM (from Rhizomucor miehei) was studied, and 4% of lipase amount was selected for further study as the optimal amount. Comparison the chemical properties (free fatty acid value, iodine value, saponification value, tocopherols, and color analysis), solidification behavior, and volatile fractions (from headspace SPME GC-MS) between com oil and SL com oil was obtained.

The objective of this study was to measure performance of young broiler chickens fed three varieties of high-oil corn (HOC 1, 2, and 3) compared with eight varieties of normal corn (NC). HOC varieties contained about 80% more oil than NC (average crude fat; 6.71% vs 3.72%) and about 29% more protein (average CP; 9.54% vs 7.38%). Each experimental diet was formulated with the same amount (55.205%) of each corn hybrid. Experiment 1 had by six dietary treatments (HOC1 and five NC varieties, 360 chickens) and Experiment 2 had five treatments (HOC2, HOC3, and three NC varieties, 250 chickens). In Exp. 1, for feed efficiency (F/G), the treatment contained HOC1 had better performance (p<0.05) than other NC varieties except NC5. As expected, there was no significant difference in average daily feed intake (p>0.05) among dietary treatments. The dietary treatment of HOC1 gave an improvement of 4.3% in F/G that came from 6% higher gross energy (GE) value of HOC1. Compared with Exp. 2, the dietary treatments contained HOC hybrids gave 4.4% higher F/G than NC dietary treatments, which came from a 5% increase in GE value. HOC varieties had superior nutrients content to NC for poultry, due to the fact that HOC contained higher concentrations of energy, protein, lysine, and methionine, thus improving growth and F/G.

The feeding value of high-oil corn fed to Taiwan Country (TC) chicken was examined by measuring apparent metabolizable energy (AME), growth performance, sexual maturity, carcass characteristics, and plasma pigmentation. In a completely randomized design, 870 sex-intermingled one-wk-old chicks were assigned to one of 30 floor pens, 29 birds per pen, and each pen randomly assigned to one of five dietary treatments. The experiment was ended when birds were 16 wk of age. The five dietary treatments varied in main fat sources, which were corn oil (CO), high-oil corn (HOC), lard (LRD), whole soybean (WSB) and yellow corn (YC), respectively. All the diets were formulated isonitrogenously, isocalorically, and of equal lysine and methionine contents except YC, in which equal amounts of YC replaced HOC. The results indicated that feed conversion in HOC was 8% higher (p<0.05) than YC whereas the calculated AME of HOC was only 3.5% to 4.0% higher than that of YC. No significant differences were observed in body weight, body weight gain, feed consumption, feed conversion ratio and ME efficiency for body weight gain among CO, HOC, LRD, and WSB. No significant differences existed in both skin and muscle pigmentation of breast among the five dietary treatments. No significance differences existed in plasma carotenoid content measured at various ages among the five dietary treatments except that birds fed with HOC had less (p<0.05) plasma carotenoids at 16 wk-old. The results indicate that if the price of high-oil corn is no more than 1.05 times that of yellow corn, the dietary cost per kg of body weight gain for TC chickens fed diets containing high-oil corn will be less, although their body weight may be lighter compared to chickens fed diets formulated with other fat sources.

By saponification and extraction of corn oil foots abandoned as waste during oil refining, a mixture of phytosterols was obtained, and its major components were determined as .betha.-sitosterol, campesterol and stigmasterol by gas chromatographic analysis. The mixture is very cheap and regarded as an excellent substrate for direct fermentation of C-17 keto steroid intermediate for various steroid pharmaceuticals.

Partial discharge (PD) detection plays a major role in the life time assessment of liquid insulation in power transformers. Many research works are being carried out to replace conventional mineral oil insulation in transformers by vegetable oils. It is necessary to understand the PD characteristics of vegetable oils before recommending them as an alternate for mineral oil. In this paper, the breakdown strength and PD characteristics of palm and corn oil were investigated in both unaged and thermally aged conditions. Laboratory experiments were performed as per IEC test procedures. PD signals were measured using wide band detection system. Phase resolved PD pattern of vegetable oils and mineral oil were compared. Effect of increase in voltage stress on the PD pattern of palm and corn oil were studied. Time and frequency domain analysis of PD pulses at needle-plane electrode configuration was carried out. Statistical analysis of PD pattern i.e. skewness and shape parameter variations with respect to applied thermal stress were also carried out. From the results, it is observed that palm and corn oils have better breakdown strength and PD characteristics even under long-term thermal stress and hence they can be used for power transformer applications.

Sophorolipid was produced by Candida bombicola ATCC 22214 from soybean dark oil, a byproduct of soybean oil processing. With a fed-batch culture of C. bombicola for 7 days, 90 g/l of sophorolipid was obtained. The CMC (critical micelle concentration) and minimum surface tension of the sophorolipid in aqueous solution were found to be 150 mg/l and 48 mN/m, respectively. The dispersion capability of sophorolipid was higher than that of the chemical surfactants such as SDS and Brij30. The molar solubility ratio (MSR) of 4-methylnaphthalene was 0.2. Linoleic and oleic acids were the main constituents of the fatty acid composition of the sophorolipid. The sophorolipid showed antimicrobial activity against Propionibacterium acne and Bacillus subtilis.

The effects of tween 20, one of neutral emulsifiers, on oxidative stability of corn oil were determined under a relative humidity (RH) range of 0-93 % at room temperature after 350 days of storage. The degree of oxidation was determined by headspace oxygen content and conjugated dienoic acids analyses. Moisture content and ${\alpha}$-tocopherol were also analyzed. The degree of lipid oxidation was significantly influenced by the concentration of tween 20 and relative humidity. Samples without addition of tween 20 showed the highest oxidative stability in 11 % RH, whereas oxidative stability was lowest at 93 % RH. Adding 0.5 and 1.0 % tween 20 increased the rate of lipid oxidation in a concentration dependent manner. Samples containing tween 20 had higher moisture content than those without an amphiphilic compound. Stability of ${\alpha}$-tocopherol was depending on the content of moisture and amphiphilic compounds in bulk oil.