• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.2
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• pp.141-147
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• 2004

This study was carried out to know the variation of soybean seed proteins, 11S and 7S globulins, and their amino acid compositions among different colored soybean varieties, 'Danbaegkong' (yellow), 'Pureunkong' (green) 'Jinyulkong' (brown), and 'Geoumjeongkong l' (black). Soybean seed proteins showed a wide range in molecular size, but the electrophoresis patterns of total seed protein subunits showed a similarity among different colored soybean varieties. Amino acid compositions of total seed proteins were similar for all soybean varieties tested. However, soybean varieties showed low composition rates in sulfur containing amino acids. The composition rates of cysteine and methionine in the 11S globulins were higher than those of total seed proteins and 7S globulins. Glutamic acid and glycine were higher in the 11S and 7S globulins than those of total seed proteins. However, the levels of methionine and phenylalanine are high in the 11S globulins, but those of valine and lysin are slightly lower than the 7S globulins. By using HPLC, we tried to analyse the soybean seed proteins. The 11S globulin was composed of 10 major peaks whereas the 7S globulin was composed of 4 major peaks. The composition rates of 11S related proteins have a tendency to increasing during the maturing whereas those of 7S related proteins have a tendency to decreasing. Composition rates of each peaks among different colored soybean varieties suggested that soybean seed proteins are varied, although they showed similarity in the electrophoresis patterns, and understanding of this characteristics is important for the utilization of soybeans.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.816-822
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• 2020

This study investigated the antioxidant activity and general and sensory properties of soybean curd supplemented with Codium fragile. The yield of soybean curd containing 0%, 20%, and 40% C. fragile was 113.62, 104.09, and 108.06, respectively. Antioxidant activities and pH were significantly increased (P<0.05) depending on the amount of C. fragile supplemented in soybean curd. Compared to that in additive-free soybean curd (control), the amount of crude ash and protein in soybean curd containing 40% C. fragile was significantly decreased (P<0.05) and increased (P<0.05), respectively. We observed a dose-dependent increase (P<0.05) in the hardness and chewiness of soybean curd concomitant with the amount of C. fragile supplemented. In contrast, we observed no significant difference (P>0.05) in soybean curd's cohesiveness between the groups. As determined by sensory evaluation based on seven-point hedonic scale, soybean curd supplemented with 20% C. fragile received an excellent score (6.55) for color. As the same method, we observed that the flavor and overall acceptability significantly increased (P<0.05) in the C. fragile content increased. Taken together, the antioxidant and sensory assays in our study make a compelling case for the practical development of soybean curd supplemented with C. fragile owing to its good antioxidant activities, general properties, and consumer acceptance.

• The Korean Journal of Food And Nutrition
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• v.36 no.2
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• pp.87-92
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• 2023

Isoflavones found in soybeans are present as glycosides and aglycones, which differ according to their chemical structure. The absorption rate and bioavailability of aglycones are greater than those of glycosides. It is known that aglycone isoflavones in soybean was converted from glycoside isoflavones by activating of endogenous β-glucosidase under drying (40~60℃) conditions after soaking. In this study, we compared and analyzed the proximate composition and isoflavone contents of soybean powders prepared under dried after soaking were analyzed. In the comparison of the proximate compositions, the moisture contents of white soybean powder dried after soaking (WSPDS) and black soybean powder dried after soaking (BSPDS) were decreased as compared with those of the control white soybean powder (CWSP) and control black soybean powder (CBSP). Whereas the contents of other proximate compositions were increased. The aglycone isoflavone contents were higher in WSPDS than in CWSP. Whereas the aglycone isoflavone contents of BSPDS had a similar content those of CBSP because of the component characteristics of black soybean. In conclusion, we believe that it is appropriate to identify and utilize the component characteristics of soybean varieties in order to induce an increase in the functional component content of soybeans under drying conditions after soaking.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.135-143
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• 2008

The ratio between 11S Sand 7S globulins was greater in large seed size varieties (LSSVs) of soybean than in small seed size varieties (SSSVs) or medium seed size varieties (MSSVs) but did not differ between MSSVs and SSSVs. The cysteine and methionine contents of 11S globulins were greater than those of total seed proteins and 7S globulins. The acidic monoamino monocarboxylic amino acids were the most abundant class of amino acid in soybean seed (27.2%) and soybean curd protein (29.3%). Isolated 7S and 11S fractions were analyzed by HPLC. Of the 12 peaks detected, 4 constituted 64.1% of the proteins of the SSSVs, 65.6% of the proteins of the MSSVs, and 70.5% of the proteins of the LSSVs. The 11S/7S globulin ratio was related to the yield and hardness of soybean curd. The MSSVs had the greatest yield of soybean curd, but the soybean curd hardness of the MSSVs was greater than that of the SSSVs. These results show that the 11S/7S ratio and color of soybean seeds can be used to predict the yield, hardness, and color of soybean curd.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.39-43
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• 1996

In order to cultivate the soybean sprout fortified with organogermanium, we observed growth characteristics and germanium content of soybean sprout watered with the aqueous organogermanium, Ge-132[bis(2-Carboxyethylgermanium sesquioxide)]. Soybean sprout did not show difference in growth when treated with different times and frequencies of organogermanium or different types of germanium. Growth of Orialtae soybean sprout was smaller in diameter of hypocotyledonary axis and longer in total length than that of Danyeob soybean sprout. Three hour's soaking was better in growth than half an boar's treatment. Germanium absorbed by soybean sprout was greater in content in Danyeob soybean sprout than in Orialtae soybean sprout and highest at 20 ppm in water. Prolonged period and increased frequency in treatments with organic germanium resulted in increase of germanium uptake. Germanium content in soybean sprout was greater with treatment of organic germanium than with inorganic germanium.

• Food Science of Animal Resources
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• v.24 no.4
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• pp.405-410
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• 2004

This study was performed to investigate the antioxidative activity of soybean products extracts using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and thiobarbituric acid (TBA) method for application of animal products. All three extracts (natto, soybean paste, soybean milk extract) were found to have an ability to donate hydrogen to DPPH. Especially, natto and soybean paste extract were more effective than that of soybean milk on the antioxidative activities. Natto and soybean paste extract were stronger than butylhydroxy toluene (BHT), butyl hydroxyl anisole (BHA) (5${\times}$10$^{-4}$ M) and ascorbic acid (5.7${\times}$10$^{-3}$ M) previously well known as antioxidants. These extracts also showed a synergistic effect. TBA values of natto (45.8％) and soybean paste extract (45.2％) were stronger than that of soybean milk extract (33.6％). These results suggest that soybean product extracts have antioxidative activities and synergistic effects.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.2
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• pp.188-193
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• 2005

As the modern medicine develops, the physique and average life span are increasing. In proportion to that, modern diseases of adult people such as cancer, obesity, arteriosclerosis, cardiac disorder become great social issues. In the meantime, as the development of a new diet brings a new attention, the study is designed to examine the availability of functional food by adding Korean traditional food, soybean Dasik, mulberry leaf. For this study, mulberry leaf was added 0, 5, 10, and $15\%$ respectively to soybean Dasik in proportion to the total weight of soybean power. These are compared with the soybean Dasik itself in relation to the nutritional composition, sensory evaluation, and mechanical characteristics. The results of the research were as follows. Nutritional composition showed that mulberry leaf soybean Dasik increased Na, Ca, K, crude fiber, and ash. As for the result of sensory evaluation of mulberry leaf soybean Dasik, the followings were turned out to be good : color - $10\%$, mulberry leaf smell - $5\%,\;10\%,\;15\%$, bitterness - $5\%,\;10\%$, softness and moistness - $0\%,\;5\%,\;10\%$, and sweetness and overall quality - all the added food group. As the test results of mechanical characteristics, mulberry leaf soybean Dasik showed statistically significant difference only in the hardness, especially high on $5\%,\;10\%,\;and\;15\%$. There were no significant differences in other characteristics. In color, mulberry leaf soybean Dasik showed that L, a and b values decreased as the percentage of addition of mulberry leaf went up. Therefore, the appropriate amount of addition for the production of mulberry leaf soybean Dasik was $5\~10\%$ mulberry leaf in proportion to the weight of soybean power.

• Journal of Food Hygiene and Safety
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• v.19 no.1
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• pp.31-37
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• 2004

This study was performed to investigate the changes of amino nitrogen, total amino acids, free amino acids, and cole. of traditional Korean soybean paste (doen-jang) during the ripening and storage for 12 months. All of the preparation methods for soybean paste followed the recommendations of the Korea Food Research Institute. The components of soybean paste were analyzed at 0, 6, and 12 months. The content of amino nitrogen of soybean paste was significantly higher than that of soybeans or meju (soybean cakes) at the initial stage of storage (p〈0.05), and decreased during the storage. The composition of total and free amino acids and their ratios of soybean paste were changed during the storage. The ratios of free to total amino acids of soybeans, meju, and soybean paste were 0.8%, 17.3%, and 20.4∼32.9%, respectively. Glutamic acid, which represents the savory taste, was detected the most abundantly in soybean paste during the storage. The ratios of free to total amino acids of glutamic acid were 21.1∼41.5% in soybean paste. Lightness, redness and yellowness of Hunter color of soybean paste decreased over time (p〈0.05). The results of this study indicate that the ratios of fee to total amino acids of soybean paste were much higher than those of soybeans, although its contents of total amino acids were much lower than those of soybeans. The results also indicate that this comes from the preparation and fermentation of meju. It was suspected that the organoleptic quality of soybean paste derived from these three components might be inferior over 1 year of storage time.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.77-81
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• 2005

To monitor GM soybean in soybean processed foods, tofu and biji, we prepared tofu and biji containing 0%, 1%, 3%, 5% and 100% GM soybean, respectively. We examined epsps gene inserted in soybean by PCR and EPSPS protein expressed in soybean using western blotting and lateral flow strip test to compare the sensitivity of these methods. A PCR product of 123 bp inserted in GM soybean was detected in all tofu and biji containing 1%, 3%, 5% and 100% GM soybean with the exception of 0% samples; however, the size of 600 bp inserted in GM soybean was only detected in tofu containing 100% soybean and in biji containing 5% and 100% soybean. In the protein level, GM soybean product was only detected in tofu and biji containing 100% GM soybean by western blotting. In addition, only biji containing 100% GM soybean was detected by lateral flow strip test. We concluded that in order to detect GM soybean efficiently in processed food, the PCR method is more sensitive than immunological methods. With the PCR method, small size product with approximately 100 bp in PCR product is sensitive to detect GM soybean in processed foods.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.426-433
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• 2007

We analyzed the isoflavone content of domestic soybeans during steaming, boiling, fermentation, germinating cultivation, fermentation, and soybean curd production. The isoflavone content of the beans was reduced by steaming and boiling, and overall reductions ranging from 16.0 to 65.0% of initial isoflavone values were detected. After 4 days of germinating cultivation, the total isoflavones of Eunhakong increased from 1,341 to $2,017\;{\mu}g/g$ and the total isoflavones of Guinunikong increased from 1,284 to $1,535\;{\mu}g/g$. The isoflavone content of the vinegar beans produced from Hwangkeumkong and Black No.1 increased from 1,877 to $1,956\;{\mu}g/g$, and from 885 to $1,956\;{\mu}g/g$ after 8 days of immersion in 4% acetic acid, respectively. During soybean curd production, significant amounts of isoflavones were lost in the whey (30-31 %) and soybean curd residue (15-20%). Only 37.4% of the isoflavones present in the original soybeans remained in the soybean curd with the hot extraction method, and 50.7% of them with the cold extraction method. Soybean curd prepared with whole soybean method, however, retained 80.7% of the initial isoflavones.