• Korean Journal of Oriental Medicine
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• v.1 no.1
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• pp.541-553
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• 1995

In order to study the stability of herbal oil(Yoo-Je), the Yoo-Je from walnut and safflower measured their rancidity by gas chromatographic analysis. The use of specificity of column for estimating the oxidative deterioration of Yoo-Je was attempted. These results suggested the possible implication of pentanal and hexanal as an stability index for rancidity evaluation of Yoo-Je.

• Korean Journal of Pharmacognosy
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• v.54 no.2
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• pp.80-87
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• 2023

Rancidity changes were examined for 6 herbal medicines, namely Persicae Semen, Armeniacae Semen, Lini Semen, Trichosanthis Semen, Arecae Semen, Myristicae Semen known to have relatively high fat content. In order to reduce rancidity of herbal medicines, samples were stored at 3 different conditions of room, refrigerating and freezing temperatures, and the rancidity was measured for 10 months with every 2 month interval. Fat content was extracted by using ethyl ether, and acid values and peroxide values, which are generally accepted indicators of fat rancidity, were measured. When storing Persicae Semen, Lini Semen and Arecae Semen at room temperature, the acid values increased as the storage period increased, and it was higher than when stored in refrigeration or freezing. The measurement of peroxide value showed more significantly higher initial degree of rancidity when Persicae Semen, Trichosanthis Semen, Arecae Semen and Myristicae Semen were stored at room temperature. It was observed that storing herbal medicines in refrigeration or freezing inhibited their rancidity compared to storing them at room temperature. To investigate the quality changes according to rancidity, the analysis of aflatoxins and indicator components showed that aflatoxins B₁ and B₂ were detected in Armeniacae Semen, Arecae Semen and Myristicae Semen, and the amount of amygdalin was well maintained within the specification standard.

• Journal of the Korean Applied Science and Technology
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• v.7 no.2
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• pp.91-100
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• 1990

• Food Science and Preservation
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• v.19 no.5
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• pp.639-644
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• 2012

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 $90^{\circ}C$ 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 $40{\mu}m$ to avoid the dependence of the reaction area during measurement. According to the FST results, lipid oxidation did not actively progress during storage at $25^{\circ}C$. 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 $90^{\circ}C$. 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 $25^{\circ}C$ showed similar patterns during storage, but at $90^{\circ}C$, 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.

• Journal of the Korean Society of Food Culture
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• v.23 no.4
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• pp.469-478
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• 2008

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$^{\circ}C$. 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$^{\circ}C$ 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$^{\circ}C$.

• Korean journal of food and cookery science
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• v.9 no.2
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• pp.88-93
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• 1993

Semi-prepared frozen muscle foods purchased from local industry were tested for lipid oxidation. The effects of various storage conditions, cooking methods, defrosting methods and reheating methods on rancidity were examined using TBA assay and sensory evaluation. TBARS values were increased faster in cooked samples than in uncooked ones during storage periods. During refrigeration of cooked samples, TBARS values were increased significantly for 15 days (p<0.001). In defrosting experiments, refrigerated defrosting was proven to be better compared with room temperature or microwave defrosting (p<0.05). For overall explanation, stepwise regression analysis was done and the results are in this order: storage conditions, cooking methods, moisture content, and lipid content. Using these 4 variables, TBARS values could be explained by 40~53%.

• Journal of Nutrition and Health
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• v.10 no.2
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• pp.27-34
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• 1977

The present study was carried out to evaluate the nutritional quality of rabbit meat protein. The composition of amino acids contained in rabbit meat was compared with those of other animal meats such as beef, pork and chicken. Also included in this study was the question whether the cooking and storage conditions affect the amino acid composition and the pepsindigestibility of rabbit meat protein. The results are summarized as follows: 1. The large variation observed from sample to sample of EAA (essential amino acid) composition in rabbit meat was found to be an interesting but peculiar property of rabbit meat protein. The most limiting amino acid of rabbit meat protein was phenylalanine, whereas methionine was the first limiting amino acid of both beef and pork proteins. Chemical scores of various meat proteins were 68, 65, 66, and 74 for rabbit meat, beef, pork, and chicken respectively. 2. In pan roasting, the EAA damaged most by heat was methionine (15%). When cooked after two months of frozen storage, lysine decreased most. 3. Higher pepsin digestibility was obtained by cooking rabbit meat after seasoned in alcohol, ginger juice, and other spices compared with various other cooking conditions without seasoning. The pepsin digestibility value was even higher for the seasoned meat than for the raw meat. 4. Among various meats tested the rabbit meat showed the lowest pepsin digestibility. 5. A simple measurement of released methionine could be used to determine relative digestibility instead of measuring $NH_2-N$ content after pepsin digestion. From all the results obtained in this study it can be concluded that rabbit meat is a good Protein food item when used fresh and stored properly to prevent rancidity problems. It is suggested to study further the peroxidation effect of unsaturated fatty acids on protein quality. This study was supported by the Ministry of Science and Technology in Korea.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.140-144
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• 1990

This study was undertaken to examine if sodium acetate and/or calcium chloride would increase the firmness and/or retard rancidity of Kakdugj (Korean seasoned pickles of cubed radish roots) during short $(at\;20^{\circ}C)$ or long $(at\;4^{\circ}C)$ period of fermentation During the fermentation periods, pH and acidity were higher in Kakdugis containing 0.3 or 0.6% Na-acetate than in the other samples at both storage temperatures. Firmness was increased with addition of 0.05% Calcium chloride and synergistic effect on firmness was observed when Calcium chloride and Na-acetate were added together. Sourness did not decreased in samples containing 0.3% Na-acetate at either fermentation periods but decreased in those containing 0.6% Na-acetate and stored for long. Saltiness was increased slightly with the addition of Calcium chloride. Compression test gave closer result to sensory evaluation than puncture test In the measurement of firmness with Instron.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.338-359
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• 2018

Soybean (Glycine max L.), a major part of Asian diet, is consumed primarily for its nutritional value. However, poor storage stability often leads to loss of nutritional value or deterioration in quality. This study focused on the storage stability of soy flour obtained from raw and roasted "Saedanbaek" soybeans packed in polyethylene (PE) and polypropylene (PPE) film bags that were stored at $4^{\circ}C$, $20^{\circ}C$ and $45^{\circ}C$ for 48 weeks. The early acid values (diene and p-anisidine) of raw soybean flour (RSF) at high temperature (HT) were higher than those at refrigerated temperature (RFT) and room temperature (RT) during 48 and 12 to 36 weeks, respectively. In the case of roasted soybean flour (ROSF), which was stored at RFT and RT, the acid and conjugated diene values gradually increased after 24 weeks. In RSF, the peroxide value increased since the beginning of the $24^{th}$ week. The p-anisidine value also increased during 12 to 36 weeks but was much lower than the values obtained from HT storage. As the peroxide values decreased, the p-anisidine values increased, indicating an inverse relationship. Lipoxygenase activity of ROSF at all storage conditions was lower than RSF. Several differences were observed between the packing materials used. This study could, therefore, provide useful information for the industrial use of soybean flour (SF).

• Journal of the Korean Society of Food Culture
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• v.6 no.3
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• pp.237-244
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• 1991

This study was undertaken to examine the effects of ginseng on the acceptability of kimchi for 9 days at $20^{\circ}C$. Kimchi was analyzed for the measurement of acidity, pH, saltiness, reducing sugar, hardness by Instron and organic acids by HPLC. Ten highly trained panelists were involved in the sensory evaluation. The data analysis revealed followings; 1. While saltiness was maintained at around 2.3% level during the entire fermentation periods, kimchi containing 2% and 4% ginseng showed higher pH, reducing sugar, hardness by Instron, and lower acidity than without ginseng. 2. Results from analysis of organic acids contained by HPLC revealed that all three groups contained relatively high concentration of oxalic acid, lactic acid and malic acid. It was also found that, as fermented progressed, the amounts of lactic acid and acetic acid increased, and those of tartaric acid and malic acid decreased while the concentration of oxalic acid did not change significantly. 3. A result of sensory evaluation revealed that kimchi containing 2% and 4% ginseng was higher in hardness, savory taste and carbonated taste, and lower in sour taste, moldy off flavor than kimchi without ginseng, thus scoring high in overall eating quality. Considering all results obtained throughout this experiments, it can be concluded that the addition of small amount of ginseng to kimchi improve overall acceptability and retard rancidity, thus increasing the period during which is eatable.