• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.371-375
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• 1997

The content of genistein and daidzein which were known to be major antioxidative compounds in soybeans were detected by $C_{18}$ reverse phase HPLC. Most of isoflavones in soybeans were detected in the methanol extract but much less amount of isoflavones in the water extract. Among the four different kind of soybeans, the isoflavone content was highest in brown soybean, followed by yellow, small black and black soybean, in the order. These isoflavones were known to be soluble in hot water, which means transfer of isoflavone content was highest in brown soybean, followed by yellow, small black and black soybean, in the order. These isoflavones were known to be soluble in hot water, which means transfer of isoflavones in soy curd into whey during soy curd processing. To identify the change of isoflavone content during processing of soybean curd, soybean curd were made from yellow, brown and black soybean and isoflavone content were determined in each soybean curd, curd residue and whey. Most of soflavones were remained in the whey, it means most of useful antioxidative compounds were wasted. Thus, it is necessary to develop new technology to collect these isoflavones lost during soybean curd processing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.139-144
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• 2001

To analyze their isoflavones contents by HPLC analysis during two years on 60 collected old local traditional soybean varieties from various districts of Korea was conducted. There was a yearly variation in the seed isoflavon concentrations. The total contents on 5 isoflavones were in the range from 16.21mg/g to 25.21 mg/g and from 6.47 mg/g to 15.44 mg/g, in 1997 and 1998, respectively. Collected soybean from Gunsnsi-1(25.21 mg/g) in 1997 and from Gangjingun-3 (16.50 mg/g) in 1998 showed the highest amount of isoflavones as compared with other collected soybean varieties. The highest amount among 5 isoflavones was genistin as 48.45% and 49.73%, in 1997 and 1998, respectively, indicating the genotypic variation in seed isoflavon contents of local soybean cultivar. Our data suggest that it may be feasible for improving soybean variety with higher antioxiadtive activity and substances.

• Korean journal of food and cookery science
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• v.21 no.4 s.88
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• pp.433-439
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• 2005

Soybean is an important plant as it is the source of protein and oil as well as various phytochemicals that are related with biological activity. Over the past decades, scientists have conducted considerable research on the physiological properties of soybeans, especially isoflavones, which are the characteristic components in soybeans. However, there is no research on the properties or the bio-functionality of soybean leaf. Jangachi and kimchi are two of the traditional special dishes of Gyungsang Province in Korea which we made from soybean leaves. Depending on the recipe, green or yellow soybean leaves are used for the preparation of these two side dishes. We compared the antioxidative activity and measured the contents of isoflavones, total phenol, chlorophylls, carotenoids, and vitamin C in the ingredients (green and yellow soybean leaf) and the final side dishes (jangachi and kimchi). We Int report that isoflavones were contained in soybean leaf and that jangachi had the highest isoflavone contents among the samples. Yellow soybean leaf contained higher isoflavones than green soybean lear and kimchi. From the TEAC assay results, the sequence or antioxidative activities was yellow soybean leaf > soybean leaf jangachi > green soybean leaf > soybean leaf kimchi. The sequence was the same with total phenol contents, indicating that antioxidative activity is highly related with total phenol level. Chlorophylls, carotenoids and vitamin C existed abundantly in green soybean leaf. In conclusion, soybean leaf could be a good material for health due to the presence of isoflavones and the other useful antioxidants mentioned above.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.3
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• pp.539-547
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• 2015

This study investigated elementary school students' perception and recognition of soybean foods and assessed their intake levels of isoflavones. A survey was administered to 300 sixth grade students in Daegu. The amount of isoflavones consumed by students was estimated by food intake frequency and the 24-hour recall method based on their general dietary habits and perception of soybean foods. Subjects' mean height was 152.2 cm, mean weight was 45.2 kg, and body mass index was $19.4kg/m^2$. All subjects had knowledge of soybeans and most preferred bean-paste pot stew of all soybean-based foods. Students typically ingested isoflavones two or three times per week in the forms of tofu, bean-paste pot stew, and bean sprouts. The average amount of isoflavones consumed from soy foods was 26.43 mg/day (daidzein 9.27 mg/day and genistein 17.16 mg/day) as assessed by food frequency questionnaire and 30.83 mg/day (daidzein 13.63 mg/day and genistein 16.40 mg/day) by the 24-hour recall method, showing that the 24-hour recall method assessment amount was 4.4 mg higher than that of the food frequency questionnaire. The major food sources of isoflavones were soybean paste and soybeans. Those who were especially knowledgeable about soybean foods expressed the view that these sources were a good or affordable enriched source of isoflavones.

• 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.

• Journal of Korean Academy of Nursing
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• v.37 no.3
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• pp.276-285
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• 2007

Purpose: This study was conducted to explore the relationship between isoflavones intake from soy foods and perimenstrual symptoms among women. Methods: The research design was a cross sectional study. Subjects consisted of 245 women living in Korea, aged 19-49 years. The measurement tools were MDQ and FFQ. Results: Frequently consumed soy isoflavones foods were rice with soybeans, soybean paste stew, and soy paste with tofu. The amounts of soy isoflavones foods consumed in order from highest to lowest were rice with soybeans, soybean paste stew, seasoned soybean sprouts, and soy paste with tofu. Subjects were divided into three groups by isoflavones intake levels; the small intake group, moderate intake group, and large intake group. There were significant differences in some menstrual symptoms, and postmenstrual symptoms by isoflavones intake levels. In general, the moderate isoflavones intake group showed lower scores in some menstrual symptoms and postmenstrual periods compared to the small and large intake groups. Conclusions: These results suggest some positive health effects of isoflavones from soy foods on perimenstrual symptoms. More accurate, objective measurement needs to be applied and more investigation of soy isoflavones effects on many aspects of women's health need to be done in a future study.

• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.117-123
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• 2016

Bioconversion of aglycone-formed isoflavones from glycoside-formed isoflavones by commercial lactic acid bacteria in fermented soybean paste was evaluated. Enterococcus faecium KCTC 13410 showed the most resistant capacity and Lactobacillus acidophilus KCTC 3925 had a sensitive susceptibility at a high NaCl concentration (13.2%) in fermented soybean paste. Among the 5 strains tested, Lac. acidophilus KCTC 3925 showed the highest relative ratio of aglycone-formed isoflavones to total isoflavones in fermented soybean paste. Production of exopolysaccarides (EPS) by lactic acid bacteria was compared using de Man, Rogosa, and Sharpe medium containing 1% sucrose at $37^{\circ}C$ for 48 h. Among the 5 lactic acid bacteria, Lac. acidophilus KCTC 3925 and Lactobacillus rhamnosus KCTC 3929 were investigated to produce EPS. Based on the results concerning growing susceptibility and conversion of aglycone-formed isoflavones/EPS production, it is anticipated that Lac. acidophilus KCTC 3925 may be used for preparation of Cheonggukjang, which contains relative low NaCl content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.spc1
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• pp.25-45
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• 1996

Soyfoods have potential roles in the prevention and treatment of chronic diseases, most notably cancer, osteoporosis, and heart disease. There is evidence that carcinogenesis are supressed by isolated soybean derived products in vivo such as a protease inhibitor, phytic acid, saponins and isoflavones. It is believed that supplementation of human diets with soybean products markedly reduces human cancer mortality rates. Especially, recent papers recognize the potential benefit of soybean isoflavone components for reducing the risk of various cancers. Isoflavones exhibit a multitude of medicinal effects that influence cell growth and regulation, which may have potential value in the prevention and treatment of cancer. In addition to potential biological effects, soybean isoflavones have the important physiological functions such as the induction of Bradyrizobium japonicum nod genes and the responses of soybean tissues to infection by Phytophthora megasperma as well as biochemical activities such as antifungal and antibacterial actions. Genistin, daidzin, glycitin and their aglycone (genistein, daidzein, glycitein) are the principal isoflavones found in soybean. Malonyl and acetyl forms have also been detected but they are thermally unstable and are usually transformed during the processing in glucoside form. Most soy products, with the exception of soy sauce, alcohol-extracted soy protein concentrate, and soy protein isolate, have total isoflavone concentrations similar to those in the whole soybean. Soybean-containing diets inhibit mammary tumorigenesis in animal models of breast cancer, therefore, it is possible that dietary isoflavones are an important factor accounting for the lower incidence and mortality from breast cancer. Of the total soybean seed isoflavones, $80\~90\%$ were located in cotyledons, with the remainder in the hypocotyls. The hypocotyls had a higher concentrations of isoflavones on a weight basis compared with cotyledons. Isoflavone contents were influenced by genetics, crop years, and growth locations. The effect of crop year had a greater impact on the isoflavone contents than that of location. The climate condition might be the attribution factor to variation in isoflavone contents. Also, while the isoflavone content of cotyledons exhibited large variations in response to high temperature during seed development, hypocotyls showed high concentration in isoflavone content. So, it is concluded that one of the factors affecting isoflavone content in soybean seeds is temperature during seed development. High temperature, especially in maturity stage, causes lower isoflavone content in soybean seed. It is also suggested that there may exist a different mechanism to maintain isoflavone contents between cotyledon and seed hypocotyls. In a conclusion, soy foods may be able to have a significant beneficial impact on public health.

• Preventive Nutrition and Food Science
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• v.12 no.1
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• pp.29-34
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• 2007

The production of mevinolin, a potent hypocholesterolemic drug, and the bioconversion of isoflavones were investigated in soybeans fermented with Monascus pilosus KFRI-1140. The highest yields of 2.94 mg mevinolins and 1.13 mg isoflavone aglycones per g dry weight of soybean were obtained after 20 days of fermentation. Mevinolin was present in the fermentation substrate predominantly in the hydroxycarboxylate form (open lactone, 94.8$\sim$96.7%), which is currently being used as an hypocholesterolemic agent. The significant (p<0.01) bioconversion (96.6%) of the glucoside isoflavones (daidzin, glycitin, genistin) present in the soybean to the bioactive aglycones (daidzein, glycitein, genistein), with a 15.8-fold increase of aglycones was observed. The results suggest that Monascus-fermented soybean has potential as a novel medicinal food or multifunctional food supplement.

• Preventive Nutrition and Food Science
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• v.2 no.3
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• pp.255-258
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• 1997

Isoflavones are associated with prevention of chronic diseases such as cancer, osteoporosis, and hypercholesterolemia. The isoflavone contents at different development stages of soybean were anayzed to examine the period of their formation and reaching maximum level. Soybean sedds have been collected from 13th to 21st week after sowing. Total daidzein and genistein contents increased from 115 and 37mg/kg at 13th week, to 795 and 699mg/kg at 21st week, respectively. Total glycitein content showed less remarkable change during seed development than other isoflavones. Thus mature soybean may have maximum preventive effect from chronic diseases since it contains the highest level of isoflavones.