• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.125-129
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• 2020

In this study we developed a method for determining the geographic origin of soybeans by combining energy dispersive X-ray fluorescence spectrometry with statistical analysis. In 2018, 197 soybean samples (100 Korean domestic samples and 97 foreign samples) were collected for the construction of a geographic origin model. The mineral concentrations of 26 elements were measured and determined via the fundamental parameters approach. One-way analysis of variance, t-test, and canonical discriminant analysis were employed to reveal five elements (P, Ni, Br, Zn, and Mn) that could be used for the determination of geographic origins. The sensitivity, specificity, and efficiency for the above method were 91.0, 95.9, and 93.4%, respectively. Validation results from 60 samples collected in 2019 showed a predictive rate of 93.3% for Korean domestic soybeans and 100.0% for foreign soybeans. In conclusion, the combination of energy dispersive X-ray fluorescence spectrometry and chemometrics could be used to effectively determine the geographic origin of soybeans.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.162-166
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• 2020

This study examined the effects of additives on the physicochemical properties of gruels during storage. The color, a-value, and b-value of fine-nut, dried pollack, soybean, and chicken gruels increased, while the L-value and whiteness decreased. In addition, the a-value, b-value, and L-value of oyster mushroom gruel decreased upon increase in the storage period. Texture analyzer measurements of gruels revealed that the gumminess, cohesiveness, adhesiveness, and hardness decreased during the storage period of 90 days. The amylose and total sugar contents were also decreased during this storage period. Majority of the fatty acid composition of the gruels during the storage period at 25℃ was due to unsaturated fatty acid. The total unsaturated fatty acid content decreased, whereas saturated fatty acid content increased during the storage period of 45 days.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.332-338
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• 2012

A simple and sensitive analytical method was developed using gas chromatography with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS) for determination of Picoxystrobin in agricultural products (apple, hulled rice, mushroom, pepper, soybean, and mandarin). Picoxystrobin residues were extracted with acetonitrile, partitioned with saline water, and then they were cleaned up on a florisil solid-phase extraction (SPE) cartridge to obtain an extract suitable for analysis by GC-ECD and GC-MS. The method was validated using 6 agricultural product samples spiked with Picoxystrobin at different concentration levels (0.02, 0.05 and 0.5 mg/L). Average recoveries of Picoxystrobin (using each concentration three replicates) ranged 64.0~98.3% with relative standard deviations less than 10%, calibration solutions concentration in the range 0.1~5 mg/L, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.02 mg/L, respectively. The result showed that the developed analytical method is suitable for Picoxystrobin determination in agricultural products.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.141-146
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• 2017

A rapid and precise method using LC-MS/MS was developed for carbendazim analysis in agricultural products. This compound was extracted with acetonitrile from agricultural products and cleaned up by solid-phase extraction procedure. The limit of detection and quantification were 0.001 mg/kg and 0.004 mg/kg, respectively. The mean recoveries and precision from 4 agricultural products, soybean sprout and mungbean sprout were in the range of 83.3-86.4% and 0.2-3.0% spiked at 1.0 mg/kg and those were in the range of 77.3-90.1% and 1.3-3.8% spiked at 0.02 mg/kg. The present method is faster and more precise compared with the multi-residue method of Korean Food Code. Therefore, we conclude that this method is suitable for carbendazim determination in a wide range of agricultural products.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.114-122
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• 2017

N-nitrosamines can be produced in the process of heating, processing, storage and packaging. Migration specifications for N-nitrosamines exist only for rubber baby bottle nipples, which are regulated by the Ministry of Food and Drug Safety (MFDS). There is no regulation for other food contact substances (FCS) and studies on N-nitrosamines migration from FCS are rather limited. A pilot study showed an increase in N-nitrosamines contents when cooking instant noodles. Thus, the migration from the packaging was suspected and it was necessary to monitor the migration of N-nitrosamines from food packaging materials and to examine the change in N-nitrosamines contents when cooking instant foods. Three N-nitrosamines, NDMA (N-nitrosodimethtlamine), NDEA (N-nitrosodiethylamine), NDBA (N-nitrosodibutylamine), were analyzed in migration test solutions from plastics such as polyethylene, polypropylene and polystyrene, papers and aluminium containers. In all test solutions, N-nitrosamines were detected less than method quantitation limits (MQLs). Food samples were also investigated to ensure that there is no effect from food contact substances when cooking instant foods. In retort sauces such as curry, black soybean sauce and tomato sauce, NDMA concentration was ranged from 0.54 to $3.81{\mu}g/kg$, but there were no significant differences between unheated and heated samples. However, the NDMA contents were significantly increased in most of the instant noodle samples tested when cooked (p < 0.05). No effects from the food contact substances or cooking water was observed. Only when the seasoning powder and noodles were cooked together was NDMA detected. Individual components (noodle, seasoning powder or dried vegetable) or other combinations such as noodles and dried vegetables did not generate N-nitrosamines. Therefore, it is speculated that NDMA may be formed from the precursors in noodles and seasoning powders when they are solubilized in a medium of water.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.59-65
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• 2014

The fatty acid composition, selected minor components, and the oxidative stability of the mixed edible oil (perilla seed oil and rice bran oil, 3:7 (v/v)) were analyzed. The fatty acid composition of the mixed oil was 32.1% of oleic acid, 30.6% of linoleic acid, 21.4% of linolenic acid, 13.0% of palmitic acid, and 1.7% of stearic acid. The mixed oil contained ${\alpha}$, ${\gamma}$ and ${\delta}$-tocopherols and tocotrienols showing the highest contents of ${\alpha}$-tocopherol. Total amount of tocopherols contained in the mixed oil was 46.63 mg/100 g oil. The composition and content of phytosterols were determined by a GC equipped with a flame ionization detector. Total quantity of phytosterols in the mixed oil was 712.80 mg/100 g oil. The most predominant phytosterol in the mixed oil was ${\beta}$-sitosterol, followed by campesterol and stigmasterol, in a decreasing order. The oxidative stability of the mixed oil was much higher than that of perilla oil, and similar to that of soybean oil, indicating the high oxidative stability of the mixed oil.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.57-62
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• 1994

Soybean oil and lard containing different level (0.02, 0.1, 1%) of methionine, lysine and some antioxi-dants (TBHQ, a-tocopherol) were stored at 60$^{\circ}C$ and heated at 180$^{\circ}C$ to compare their antioxidative effects. Peroxide values (POV) and acid values (AV) of each oil were monitored. Methionine and Iysine showed antioxidative effects in all concentration and the higher concentration, the higher effect. In case of incubating antioxidative effect of methionine was similer to that of TBHQ and that of lysine was considerably higher than that of a-tocopherol, but was lower than that of methionine. In case of heating the antioxidative effects of methionine and lysine were showed higher than those of THHQ and u-tocopherol. Methionine and lysine also had higher antioxidative effects in animal fat than in vegetable oil. Synergistic effects among methionine, Lysine and some food antioxidants were shown to be available in all substrates and the best effect was shown in substrate added com-pound of methionine and a-tocopherol.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.919-926
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• 2005

The effects of the addition of germinated whole soy flour on dough and noodle characteristics were investigated in this study. The soybeans were germinated for 12 hours at $20^{\circ}C$ and ground to 60 mesh. With increasing soybean flour addition up to $16\%$, the RVA viscograph and mixograph properties were significantly decreased both with and without the addition of $3\%$ salt(p<0.05). The width and length extensibility were increased with increasing whole soy flour addition up to $8\%$ after which they decreased. The addition of the whole soy flour turned the color of the wet and cooked noodle a little darkish and greenish yellow. The hardness and gumminess of wet noodle increased with increasing whole soy flour amount, while those of cooked noodle gradually decreased. Sensory evaluation showed that addition of tile whole soy flour significantly increased the savory flavor and yellowish color of cooked noodle.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.536-539
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• 2002

This study was investigated for the preparation method of meju by three step fermentation. The steamed soybeans were fermented with nisin-producing Lactococcus lactis subsp. lactis IFO12007 to inhibit the growth of odor-producing Bacilli and promote of normal fermentation of meju. The lactie-fermented soybeans were further fermented with Aspergillus oryzae and Bacillus subtilis. The produced meju by this method showed 54%moisture content and pH 7.0, respectively. The three step fermented meju was soaked in 20% (w/v) brine at $25^{\circ}C$ for 90days. After 30 days, the contents of total free amino acids revealed 4,015 mg% which were higher $3{\sim}5$ times than controls. Among the detected free amino acids, the contents of glutamic acid and leucine showed 925 mg% and 380mg%, respectively. Therefore, the new method of producing meju would be an excellent alternative to improve the quality of soybean fermented food, such as doenjang and kanjang.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.498-504
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• 2002

Isoflavone (daidzein and genistein) contents, and antioxidative and fibrinolytic activities of seven commercial Korean cooking-with-rice soybeans, including Seonbikong, Chungtae, Gangnamkong, Whangtae, Geodoo, Seolitae, and Wooltalikong were investigated. Daidzein and genistein were not found in Selitae, nor was didzein in Gangnamkong and Geodoo. Total daidzein and genistein levels in Chungtae and Whangtae were 500 and 1550 mg per kg, respectively. Wooltalikong, Whangtae, and Gangnamkong had very high electron donation abilities, over 90%, but Seonbikong and Chungtae showed significantly lower activities. SOD-like activities were also the highest in Gangnamkong and Wooltalikong. Fibrinolytic activities in Seonbikong, Whangtae, and Gangnamkong were similarly strong. Fibrinolytic substances purified from protease inhibitors or activated under various pH or heat treatment conditions, were different among the soybean varieties. This study revealed that, although several cooking-with-rice soybeans were poor in isoflavones, Wooltalikong and Gangnamkong could be good sources for functional products due to their strong antioxidative activities, and heat- and acid-resistant proteolytic abilities.