The purpose of this study is to investigate the effect of superheated steam (SHS) treatment on the inactivation of an enzyme involved in the racidity of brown rice as well as the degree of rancidity during storage of brown. Brown rice was treated with SHS at temperatures of 160oC, 200oC, and 240oC, and the result showed that the degree of starch damage was higher in the brown rice treated with SHS at higher temperature. Lipoxygenase was inactivated by treating with SHS for 20 s at 160oC, 15 s at 200oC, or 5 s at 240oC. The acidity and sensory evaluation of the brown rice treated with SHS showed that the acidity was decreased as the SHS treatment increased and SHS temperature became higher. The result of the sensory evaluation showed a similar tendency. These results show that the SHS treatment has potential as a method for improving the brown rice storage quality.

The rancidity of soybean (Glycine max L.) in powder forms was evaluated by fluorescence spectrum test (FST). The results from the FST were validated by comparing those of 2-thiobarbituric acid (TBA) value and acid value. The storage temperature and time of soybean powders were at the room temperature, 50, and 90oC for 20 days. The maximum excitation and the maximum emission of fluorescent compounds generated from the soybean powder during storage were observed at the wave length of 360 nm and 430 to 440 nm, respectively. The mean particle size of soybean powder was controlled to be 40 μm. The FST results showed that the lipid oxidation during storage at room temperature and 50oC was not progressed actively (p < 0.05), but dramatically progressed at 90oC. All the values at room temperature and 50oC showed a similar pattern during storage. But, at 90oC, the FI (fluorescence intensity) values and the acid values showed similar pattern. The results demonstrated that FST might be useful to measure the rancidity of soybean powder because FST did not require oil extraction to measure the rancidity.

대두에서 산패취를 발생시키는 lipoxygenase 효소를 비가열 전처리 방법인 초고압 처리 방법을 이용하여 효소의 활성도의 변화를 확인하였다. 연구 결과 초고압 처리에 의해 lipoxygenase 효소의 활성도가 감소하는 것을 확인하였다. 또한 lipoxygenase 효소의 활성도 감소에 의해 대두의 저장성에 미치는 영향을 확인하기 위해 국산 대두와 연해주 대두를 이용하여 저장 실험을 실시하였다. 실험 결과 국산 대두의 경우 초고압 처리에 의해 lipoxygenase 효소의 활성도가 감소하였으나 TBA값에 영향을 주는 자동산화 등의 화학반응에 의해 TBA값이 지속적으로 증가함을 보여주었다. 그러나 연해주 대두의 경우에는 초고압 처리를 한 시료의 TBA값의 증가정도가 상대적으로 낮게 측정된 것을 확인하였다. 이는 연해주 대두가 항산화 성분을 국산콩에 비하여 많이 포함하고 있어 초고압 처리에 의한 lipoxygenase 효소의 불활성과 함께 항산화 성분의 영향으로 TBA값의 저장 중 증가 정도가 낮게 측정된 것으로 판단되어진다.

In this study, degree of rancidity and trans fatty acid formation were examined in fat and oils, including soybean oil (SB), canola oil (CA), corn germ oil (CO), olive oil (OL), palm oil (PO), and beef tallow (BT), during heating for 10-130 minutes at 160-200℃. In order to determine the rancidity of the fat and oils, acid values (AV), iodine values (IV), viscosity, and color were measured. Changes in the amounts of fatty acids and the formation of trans fatty acids were measured using GC and HPLC. For all groups, AV increased, IV decreased, and coefficients of viscosity and color increased as the heating temperature and heating time increased, indicating there were positive correlations between the heating temperature and time and AV. In addition, all groups had similar amounts of trans fatty acids, with the exception of the beef tallow; however, its level only slightly increased with heating. The olive oil had the lowest trans fatty acid content and the lowest amount created by heating. The order of trans fatty acid amounts generated while heating was BT〉PO〉CO〉CA〉SB〉OL. According to the study results, the deep frying temperature during cooking should be 160-180℃ in order to reduce AV and the amount of trans fatty acids that are formed. In addition, it is better to remove beef tallow during cooking and avoid heating at high temperatures since it results in high levels of trans fatty acids. The correlation between the amount of trans fatty acids and AV was positive, while the correlation between the amount of trans fatty acids and IV was negative, indicating that AV and trans fatty acid levels increase while IV decreases as the deep frying temperature and time increase. From the results, it was found that reducing the deep frying temperature and time can lessen increases in AV and trans fatty acids, and decrease IV. Accordingly, to reduce AV and trans fatty acid formation, the ideal deep frying conditions would be to use olive oil or soybean oil rather than beef tallow or palm oil at a temperature of 160-180℃.

식용대두유의 항온저장시 tryptophan과 arginine의 첨가농도에 따른 항산화 효과 및 기존 항산화제들의 항산화력에 대한 상승효과를 조사한 결과는 다음과 같다. 유지의 항온저장시 tryptophan과 arginine을 각 농도별로 첨가한 경우 모든 시료에서 항산화 효과를 나타냈으며 특히 tryptophan 1%를 첨가하였을 때 가장 효과가 좋았고 그 정도는 TBHQ를 첨가한 경우와 비슷하였다. 또한 tryptophan과 arginine첨가시료는 α-tocopherol보다 월등히 높은 항산화 효과를 보였다. tryptophan과 arginine을 α-tocopherol, ascorbic acid, citric acid와 혼합하여 대두유에 첨가했을 때 α-tocopherol과의 혼합물이 상승효과가 가장 높았다. 또한 citric acid나 ascorbic acid의 혼합물도 약하지만 상승효과를 보였다. 이상의 결과를 볼 때 tryptophan과 arginine은 유지에 대하여 항온저장시 모두 항산화 효과가 있었으며 특히 1%농도에서 가장 높게 나타났고 다른 항산화제와 병용했을 때 상승효과가 매우 우수하였음을 알 수 있었다.

Customary usage of oil at homes and rancidity of edible soybean oil by cooking frequency at homes and mass meal services were investigated. 80% of house wives bought the cooking oil by 1.8 f unit container and 70% of them read either the manufactured date or explanatory note for use. 85% of house wives kept oil in the storage case under sink or in the pantry chest, and 80% of oils were used once or twice and 20% used three times for cooking. Acid value(AV), iodine value(IV), peroxide value(POV), carbonyl value(CoV) and thiobarbituric acid value(TBAV) of fresh soybean oil were lower than standard level. In the rancidity by cooking frequency, the acid value, peroxide value, carbonyl value and thiobarbituric acid value increased significantly when oil was used once and iodine value decreased significantly when used once and twice at both mass meal services and homes. The level of the acid value, iodine value, carbonyl value and thiobarbituric acid value of oil used at mass meal services did not show significant difference from those of oil used at homes. But, the peroxide value of oil used thrice at mass meal services was significantly higher than those of homes.

Chloroform:methanol {2:1(v/v)} 추출(抽出)한 참깨기름에 무색(無色), 청색(靑色), 적색투명(赤色透明) 셀로판 필름으로 덮개를 한 실험구(寶驗區)에는 시료(試料)무게에 대(對)하여 각각(各各) 0.02%의 BHA와 BHT를 첨가(添加)하여 일사광선하(日射光線下)에서 하루에 4시간(時間)동안 조사(照射)시켰을 때의 이들의 항산화효과(抗酸化效果)를 과산화물가(過酸化物價), carbonyl가(價), TBA가(價), 지방산(脂肪酸) 조성(組成)의 변화(變化)를 통(通)해 관찰(觀察)하였다. 항산화제첨가구(抗酸化劑添加區)의 경우(境遇) BHT가 BHA보다 산화억제효과(酸化抑制效果)가 컸으며 BHT나 BHA 모두 조사일수(照射日數)가 경과(經過)할수록 그 효과(效果)는 감소(減少)하였다. 적색(赤色) 및 청색(靑色) 투명(透明) 셀로판 필름은 강(强)한 산화억제효과(酸化抑制效果)를 나타내었으며 특히 적색(赤色)이 청색(靑色) 투명(透明) 셀로판 필름보다 강(强)한 효과(效果)를 보였다. 이는 적색(赤色)이 청색(靑色)보다 단파장영역(短波長領域)의 광선투과율(光線透過率)이 낮았기 때문인 것으로 생각된다. 적색(赤色), 청색(靑色) 투명(透明) 셀로판 필름과 BHA, BHT의 산화억제효과(酸化抑制效果)를 비교(比較)해 본 결과(結果), 적색(赤色) 및 청색(靑色) 투명(透明) 셀로판 필름이 BHA나 BHT 보다 저장초기(貯藏初期)부터 지속적(持續的)인 산화억제효과(酸化抑制效果)를 보였다. 추출(抽出) 직후(直後)의 참깨기름의 지방산(脂肪酸) 조성(組成)은 주로 oleic acid (37.7%), linoleic acid(43.4%)로 구성(構成)되었으며 착색(着色) 투명(透明) 셀로판 필름을 덮은 시료(試料)를 하루 4시간(時間)씩 일사광선하(日射光線下)에서 10일(日)동안 조사(照射)시킨 후(後)의 지방산(脂肪酸) 조성(組成)을 살펴본 결과(結果) oleic acid의 함량(含量)이 control의 경우(境遇) 1.7%, 청색(靑色)은 0.6%, 적색(赤色)은 0.2% 각각(各各) 증가(增加)하였으며 linoleic acid는 control이 4.3%, 청색(靑色)이 4.2%, 적색(赤色)은 2.1%씩 감소(減少)하였다.

In order to know the quality changes of the fat and oil foods packed in plastics film by the sunlight, we examined the sunlight transmitting rate by the kind of films and measured the acid value and peroxide value according to it. The results obtained were as follows : 1. The sunlight transmitting rate of various films was explained especial permeability under the wavelength of less than 300nm, but it marked a regular form under that of more than 30nm. 2. The vacuum evaporation film with aluminum on the polyester shuts off most of the sunlight, therefore, it has the best effect that keeps the fats and oils off rancidity. 3. The sunlight transmitting rate of the white color printing film drops about 80% as compared with not printing. 4. The preventive power against the rancidity of fats and oils is PET/Al, PET, PE, nylon and OPP film in that order. The changes of peroxide value and acid value were approximately the same as that of the sunlight transmitting rate.

Background: Sancho (Zanthoxylum schinifolium Siebold and Zucc) oil is used as a traditional medicinal material to treat severs stomach inflammation and as a diuretic. This study was carried out to investigate the effect of addition of antioxidants and blended oil the storage stability and safety of the biomaterial. Methods and Results: The effects of temperature and light on sancho oil were investigated, and the ability of antioxidants in preventing rancidity of the oil was discovered. Under fluorescent light and in darkness, the acidity of the oil was much lower than that under direct sunlight. The addition of antioxidants decreased the acid value of sancho oil; the antioxidant that showed the best results in this regard was 0.5% propolis. The acid value of canola oil, which had the lowest acid value compared with that of other oils, and blended oil, containing 5% canola oil in sancho oil, decreased by 5.5% and 15%, respectively. About one acid value decrease was observed for every 1% increase in blending with canola oil. As the concentration of canola oil increased, the viscosity and the elightness (L valu) of sancho oil increased slightly, while the blueness (b value) decreased. Conclusions: The results of this study may contribute to ensuring food safety during preservation and the industrialization of the presevation of sancho oil.

In this study, we investigated the inhibition effect of various herbs on the rancidity of soybean oil. The antioxidant activity of herb-infused oils was evaluated by examining their total phenolic contents and DPPH radical scavenging abilities. The total phenolic contents were found to increase with addition of herbs to the soybean oil. Rosemary-infused oil (RO) exhibited the highest total phenolic contents (77.28 μg GE/mL), followed by the lemon-balm-infused oil (LO), green-tea-infused oil (GO), and soybean oil (SO) alone (36.82, 36.66, and 21.24 μg GE/mL, respectively). Similary, the DPPH radical scavenging activity of the herb infused oil also increased. Moreover, measurements on the total polar compound (TPC) contents, acid value, and p-anisidine value were carried out in order to confirm the changes in the rancidity of the oils during frying. The time for the TPC content to reach 25% was confirmed to be delayed from 62 h for SO to 68 h, 74 h, and 80 h for GO, RO, LO, respectively. Even though there were some differences between the p-anisidine and acid values, it was confirmed that the addition of herbs inhibited the rancidity of soybean oil. Therefore, the results in this study show that adding herbs to soybean oil could positively contribute to the inhibition of oxidation and rancidity.

The rancidity of soybean (Glycine max L.) from Yeonhaeju, called “Bazaz”, in powder forms was evaluated through a fluorescence spectrum test (FST). The results from the FST were validated by comparing the TBA and acid values. Soybean powders were stored in 25, and 90℃ for 20 days. The maximum excitation and maximum emission of fluorescent compounds generated from the soybean powder during storage were observed at the 360 nm and 430-440 nm wavelengths, respectively. The mean particle size of soybean powder was maintained at 40 μm to avoid the dependence of the reaction area during measurement. According to the FST results, lipid oxidation did not actively progress during storage at 25℃. The fluorescence intensity (FI) from FST on the first day of storage was not significantly different from that on the last day of storage (day 20; p < 0.05), but the FI dramatically increased at 90℃. A smooth increase was observed in the initial stage; then, after 11 days of storage, the FI value increased by nearly 100% compared to that on the first day. The FI values were compared with TBA and acid values that were measured under the same storage conditions. All the values at 25℃ showed similar patterns during storage, but at 90℃, the FI and acid values showed similar patterns but the TBA decreased after reaching the maximum values on storage day 12. The results demonstrated that FST may be useful for measuring the rancidity of the powder form of soybean because it does not require extraction to measure the rancidity.