• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.41-50
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• 1990

Soy protein was isolated from Korean soy bean 'Chang ryub' and chemically modified with succinic anhydride. Functionality of the soy protein isolate(SPI), succinylated SPI(SPPI), and PP590(commercial) at various pH were investigated. The mechanical and sensory properties of soy bean curds made from several mixing ratio of succinylated soy bean milk were observed. The solubility of SPI significantly increased with succinylation. The solubility of PP590 was lower than that of SSPI. The solubility of SPPI increased significantly in 0.03M CaCl2 solution. The emulsifying activity of SSPI increased. On the range of pH above pI the emulsifying activity of PP590 was higher than that of SPI. There was no difference in emulsion stability among the groups. The foam expansion capacity of SPPI increased at higher pH than pI but the foam stability decreased significantly above pH 9. Mechanical texture profile analysis revealed the modified soy bean curds had the lower hardniss, chewiness and cohesiveness with increased modification. The mechanical characteristics of modified soy bean curds revealed generalized Maxwell Model of 7-elements or 5-elements. In sensory evaluation, the hardness, the springiness and acceptability of modified soy bean curds were lower significantly than those of control soy bean curd.

• Journal of the Korean Society of Food Culture
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• v.21 no.3
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• pp.330-335
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• 2006

The objectives of this study were to characterize the quality of soy kefir made with soymilk in combination with fructose (5%, 10%) and one of the extracts from orange (10%, 15%) and grape (5%, 10%) with differently adjusted amounts as defendant variables. The lactic acid bacteria, yeast and total microbial counts of soy kefir were respectively $1.3{\times}10^7$ CFU/ml, $1.6{\times}10^8$ CFU/ml, $1.5{\times}10^8$ CFU/ml, soy kefir was propered to drink. pH of soy kefir mixed by orange and grape extracts was decreased significantly according to add fructose 5%. Acidity became significantly high when orange and grape extracts were added, which means acidity showed similar tendency in the opposite direction. The saccharinity of soy kefir was not significantly in orange extract, but soy kefir added fructose 10% was high more than fructose 5% in grape extract. In sensory evaluation, soy kefirs added orange extract 15%, fructose 5% and grape extract 10%, fructose 5% were estimated highly on color, astrigent taste, sour taste, mouth feel and overall quality.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.205-210
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• 2015

The objective of this study was to develop yogurt-cheese using cow’s milk, ultrafiltrated cow’s milk, and soy milk. The addition of soy milk and ultrafiltrated milk increased the amount of protein in the yogurt-cheese. Yogurt-cheeses were made using cheese base using 10% and 20% soy milk with raw and ultrafiltrated cow’s milk, and stored at 4°C during 2 wk. The yield of yogurt-cheeses made with added soy milk was decreased and the cutting point was delayed compared to yogurt-cheese made without soy milk. Yogurt-cheese made using ultrafiltrated cow’s milk showed the highest yield. However, yogurt-cheese made with added soy milk had higher protein content and titratable acidity than yogurt-cheese made using raw and ultrafiltrated cow’s milk. Fat and lactose contents in the yogurt-cheese made with added soy milk were lower. Yogurt-cheeses made with added soy milk contained several soy protein bands corresponding to the sizes of α₂-, β-, and κ-casein band. Yogurt-cheese made with added soy milk had similar elasticity to yogurt-cheese made without soy milk but had lower cohesiveness. There was no significant difference in the number of lactic acid bacteria in the different cheeses, as all had over 8.0 Log CFU/g. Considering these data and the fact that proteins and fats of vegetable origin with high biological value were observed as well as unsaturated fats, yogurt-cheese made with added soy milk can be considered to be a functional food.

• Journal of Environmental Health Sciences
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• v.30 no.1
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• pp.22-28
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• 2004

This study was performed to investigate the changes of amino nitrogen, total amino acids, free amino acids, and color of Korean traditional soy sauce (kan-jang) during the ripening and storage for 12 months and the characteristics of the changes. All of the preparation methods for soy sauce followed the recommendations of the Korea Food Research Institute. The components of soy sauce were analyzed at 0,6, and 12 months. The contents of amino nitrogen of soy sauce were 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 content of total amino acids of soybean sauce was significantly lower than that of soybeans, and the content of free amino acids was higher than that of soybeans (p<0.05). The contents of total and free amino acids decreased in soy sauce after 12 months of storage (p<0.05). The composition of total and free amino acids and their ratios of soy sauce were changed during the storage. The ratios of free to total amino acids of soybeans, meju, and soy sauce were 0.8％, 17.3％, and 53.1-59.8％, respectively. Glutamic acid, which represents the savory taste, was detected the most abundantly in soy sauce during the storage. The ratios of free to total amino acids of glutamic acid were 42.9-59.5％ in soy sauce. Lightness of Hunter color of soy sauce decreased over time (p<0.05). This study indicates that the ratios of free to total amino acids of soy sauce were much higher than those of soybeans, although its contents of total amino acids were much lower than those of soybeans. This study also indicates that this comes from the preparation and fermentation of meju. It was suspected that the organoleptic characteristics of soy sauce derived from the amino nitrogen, amino acids, and color might be inferior over 1 year of storage time. However, more detailed research should be conducted to interpretate this characteristics more accurately.

• Korean Journal of Food Science and Technology
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• v.20 no.5
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• pp.625-630
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• 1988

Phosphorylation of soy protein by sodium trimetaphosphate and acetylation of soy protein by acetic anhydride were performed. Then, the functional properties of modified soy proteins were compared with that of unmodified soy protein. Isolated soy protein prepared from defatted soybean flake had protein content of 92.7% as moisture-free basis. The phosphorylated soy protein showed higher solubility, foaming properties, and water holding capacity than unmodified soy protein. Acetylation of soy protein increased emulsification activity and foaming properties greatly, whereas decreased the solubility at pH 8.0. Isoelectric pHs of phosphorylated and acetylated soy protein were shifted to acidic regions(pH 3.0 and pH 4.0) from pH 5.0, which was the isoelectric pH of unmodified soy protein. Soy protein seems to be aggregated during phosphorylation and acetylation procedure, judging form Sepharose CL-4B gel filtration profiles. The modified soy proteins showed increased mobilities to anode direction in disc-gel electrophoresis.

• Journal of Nutrition and Health
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• v.36 no.5
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• pp.452-458
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• 2003

Soybean is a rich source of isoflavones such as genistein and daidzein. Soy isoflavones have both weak estrogenic and anti-estrogenic effects and are structurally similar to tamoxifen, an agent that has an effect similar to that of estrogen in terms of reducing postmenopausal bone loss. The purpose of this study was to determine the effects of differences in protein source (casein vs soy) and isoflavone levels (reduced vs higher levels) on selected bone markers and hormones in growing male rats. Thirty weanling Sprague-Dawley young rats were divided into 3 groups: The control group was fed a casein-based diet, the soy concentrate group was fed soy protein with totally reduced isoflavones content (isoflavones 0.07 mg/g protein), and the soy isolate group was fed soy protein with a higher than normal isoflavones content (isoflavones 3.4 mg/g protein). The degree of bone formation was estimated by measuring serum osteocalcin and alkaline phosphoatase (ALP). By determining collagen cross-linkage by immunoassay and correcting with creatinine values, the bone resorption rate was compared. Serum osteocalcin, growth hormone, estrogen and calcitonin were analyzed using radio immunoassay kits. The bone formation marker and ALP activity were differentiated by protein source, showing higher values than casein in feeding either soy isolate or soy concentrate. In this study using growing rats, the differences in isoflavone contents were not a significant factor in either bone formation or bone reaborption markers. Moreover, the soy isolate group had significantly higher levels of growth hormone than the casein group. The findings of this study suggest that growth hormone is partially responsible for its bone-formation effects in young growing rats. Soy protein and the isoflavones in soy protein are beneficial for bone-formation in growing male rats. Therefore, exposure to soy protein and isoflavones early in life may have long-term health benefits in preventing bone diseases such as osteoporosis. Further study to evaluate the mechanism of action of isoflavones on bones is warranted. (Korean J Nutrition 36(5): 452∼458, 2003)

• Food Science and Preservation
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• v.30 no.5
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• pp.875-884
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• 2023

In this study, the quality characteristics of texturized vegetable proteins (TVP) produced from defatted soy flour (DSF) were analytically compared with those of texturized vegetable proteins produced with isolated soy protein (ISP) and non-defatted soy flour (SF). The base raw material formulation consisted of 50% soy proteins, 30% gluten, and 20% corn starch. A cooling die-equipped extruder was used with a barrel temperature set at 190℃ and screw rotation speed of 250 rpm. With respect to the hardness of isolate soy proteins, that of soy flour and defatted soy flour was 22.4% and 68.8%, respectively, and gumminess was 17.6% and 44.3%, respectively. Defatting increased chewiness, shear strength, and springiness. Moisture content was higher in soy flour than in defatted soy flour, while there were no significant differences in terms of water absorption and turbidity. The pH was higher with soy flour than with defatted soy flour. Concerning color, the L and b values were higher with soy flour, while the a value was higher with defatted soy flour. These results suggest that defatting soybeans can improve the quality of plant-based proteins. Further research is needed to address the quality differences from those of isolated soy proteins.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.761-769
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• 2011

The objective of this study was to investigate the physicochemical properties of Korean traditional soy sauces made with soybeans sown in different producing regions(Hadong, Paju) and in different seeding periods(late-May, mid-June, late-June). The total acidity, salt content, chromaticity, browning, amino nitrogen content and the reducing sugar content of the soy sauce samples were compared. It was found that the total acidity level and the amino nitrogen contents were significantly lower in the soy sauce made with mid-June soybeans, and that these properties increased as the sauce aged. Salt content increased with the aging period regardless of the region of production. The reducing sugar content of Paju soy sauce was the highest in late -June, and for the Hadong region, highest in late-May. The sauce made with Hadong soy beans showed an increase in reducing sugar content positively correlated with the aging period. Reducing sugar content in the samples of Paju soy sauce decreased up to 60 days of aging, but increased after this point. In Paju soy sauce, the brightness(L value) was significantly higher in mid-June, and the Hadong variant it was higher in late -May. The yellowness(b value) at the beginning of the aging process was high in late -June for Hadong soy sauce, but overall it was higher in the mid-June period. The more matured soy sauce samples were darker and showed both higher a and b values. The browning was the lowest in the mid -June regardless of the regions and it increased with the aging period regardless of the production regions. The salt, amino nitrogen contents, browning and yellowness showed significant correlations among the samples. In conclusion, the seeding period of soy beans may affect the characteristics of produced soy sauce alongside the aging conditions.

• Journal of the Korean Society of Food Culture
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• v.26 no.5
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• pp.513-520
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• 2011

This study was carried out to investigate the physicochemical properties of mung bean starch and the texture of cold-stored (5$^{\circ}C$ for 0, 24, 48, and 72 hours) mung bean starch gels added with soy bean oil (0, 2, 4, 6%). The swelling power of mung bean starch added with soy bean oil did not significantly change, whereas solubility increased significantly. Soluble carbohydrate content of mung bean starch added with soy bean oil decreased without any significant differences, whereas soluble amylose content decreased significantly. In RVA viscosity, pasting temperature and peak viscosity of mung bean starch added with soy bean oil were not significantly different, whereas minimum viscosity decreased and breakdown and consistency increased significantly. In RVA viscosity, there were no differences according to concentration of soy bean oil. DSC thermograms show that onset temperature of mung bean starch added with soy bean oil did not significantly change, whereas the enthalpy increased in the case of 4% and 6% oil addition. Rupture properties of freshly prepared mung bean starch gels added with soy bean oil increased in the case of 2% and 4% oil addition, and oil addition to mung bean starch gels suppressed changes in rupture properties during cold storage. There were no significant differences in the texture of freshly prepared mung bean starch gels added with soy bean oil, whereas hardness, chewiness, and gumminess of cold-stored mung bean starch gels added with soy bean oil decreased. In the above textural charactristics, there were no differences due to concentration of soy bean oil. Thus, the addition of 2-4% soy bean oil to mung bean starch is appropriate for improving the quality characteristics of cold-stored mung bean starch gels.

• Journal of Nutrition and Health
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• v.38 no.5
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• pp.335-343
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• 2005

Rodent models have been used to study the anticarcinogenic properties of the soy isoflavones, particularly genistein, but there is little information regarding the pharmacokinetics of the absorption and excretion of genistein. In this study, rats were given a single oral dose of genistein (20 mg/kg body wt) or an equivalent dose as Myougjoonamul-kong and Myoungjoonamul soy sprouts. Concentrations of genistein were measured in plasma, urine and feces at intervals up to 48hr after dosing. Maximum peak of plasma genistein concentration is 8 hr after dosing, and its concentration is 13.2, 7.4mol/L in soy and soy sprout-treated rats, respectively. In pure genistein treated rats, maximum peak of plasma genistein concentration is 2hr after dosing (5.7 mol/L). The percentage of dose recovered in urine over 48hr was not different between groups ($21.2\%$ soy treated; $18.2\%$ soy sprout treated; $16.1\%$ pure genistein treated). There were no significant differences between groups in the recovery of genistein in feces ($19.5\%,\;7.5\%\;and\;15.7\%$ of doses, respectively). $6.9\%\;and\;6.07\%$ of the daidzein from the soy and soy sprout treated was recovered in the feces.