• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.146-151
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• 2006

Isoflavone in soybean is known to have the important physiological functions such as antioxidative, estrogenic, and anti-tumor activities. Therefore, isoflavone content is considered as important aspect of soybean quality. The objectives of this study are to determine the isoflavone contents of soybean germplasms including major cultivars in Korea, and to provide the basic information of isoflavone far development soybean cultivar containing high isoflavone content. Among 43 Korean major cultivated soybean samples, the total isoflavone contents were varied from $277.0{\mu}g/g\;to\;2,002.0{\mu}g/g$, and the average total isoflavone content was $1,017.3{\pm}390.0{\mu}g/g$. Total isoflavone content of Seokryangputkong $(2,002{\mu}g/g)$ was the highest among those of the other cultivated soybeans. On the other side, Hwangkeumkong $(277{\mu}g/g)$ contained lower isoflavone than other cultivars. The total isoflavone content of vegetable use or early maturity soybean cultivar $(1,438{\pm}493.7{\mu}g/g)$ showed more higher total isoflavone content than others. The daidzein, glycitein, genistein and total isoflavone contents of 648 soybean germplasms collected in Korea, were ranged $16.9{\sim}2,019.8{\mu}g/g,\;0{\sim}294.9{\mu}g/g,\;38.5\sim1,337.7{\mu}g/g,\;and\;82.6{\sim}3,479.2{\mu}g/g$, respectively, and total isoflavone content of IT 180001 line $(3,479.2{\mu}g/g)$ was the highest among those of other soybean germplasm lines.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.81-88
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• 2006

The 117 soybean cultivars were collected from nine provinces in Korea, and various seed quality traits along with isoflavone contents were evaluated to elucidate their relationship. The 100-seed weight of the black soybean (31.2 g) was significantly higher (p<0.05) than yellow soybeans (28.6 g). The composition of genistein, daidzein, and glycitein accounted for 75.8, 22.8, and 1.4 % of total isoflavone in yellow soybean cultivars, while their compositions in black soybeans were 58.5, 39.7, and 1.8%, respectively. The mean contents of total isoflavone in yellow and black soybean were $l,561.6{\mu}g\;g^{-1}\;and\;l,018.3{\mu}g\;g^{-1}$. The isofalvone content showed significant variation among cultivars when classified by the seed size. In the yellow soybeans, total isoflavone content was higher in small size soybean cultivars $(1,776.0{\mu}g\;g^{-1})$ and medium size soybean cultivars $(1,714.3{\mu}g\;g^{-1})$ compared to large size ones $(1,518.5{\mu}g\;g^{-1})$. Genistein content was proved as the major factor determining the relationship between isoflavone content and 100-seed weights (r =-0.206*). Daidzein and glycitein, however, showed no significant relationship with the 100-seed weights. Isoflavone content was not significantly correlated with color parameters L (lightness) and a (redness) values, but color parameter b (yellowness) was positively correlated with glycitein (r=0.264*) in the yellow soybeans, while its negative correlation between daidzein (r=-0.245*) and total isoflavone (r=-0.256*) were observed in black soybeans. However, these findings suggested that the seed color value may not serve as an effective parameter for estimating the isoflavone intensity of the soybeans. Variation of protein and lipid contents between yellow soybeans (n=58) and black soybeans (n=59) was relatively stable, however, protein and lipid contents have no significant relationship with isoflavone content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.792-798
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• 1994

In order to investigate the antioxidant activity of phenolic compounds contained in domestic Meju and Doenjang , the methanolic extract from defatted Meju and Doenjang was fractionated into the phenolic acid and the isoflavone fractions by alumina column and polyamide-6 column chromatography, respectively. Both phenolic acid and isoflavone fractions exhibited an identical antioxidative effect against the oxidation of linoleic acid. GC analysis revealed that the phenolic acid fractio contained vanillic , chlorogenic ,p-coumalic , ferulic, and caffeine acid. The content of caffic acid was greater than 70% in the phenolic acid fraction and the content of vanillic and chlorogenic acids were disappeared during fermentation, and thus, the facts are thought to be reasons for the low antioxidant activity of the phenolic aicd fraction from Doenjang. Similarly, the isoflavone fraction cotained daidzin, glycitin-65-0 glucosider and genistin and their aglycons such as daidzein, glyciten and genistein. The content of daidzin and genistin in Meju dramatically decreased at the early stage of fermentation ,whereas the content of daidzein an dgenistein rather increased ; however, these change in isoflavone contents did not affect the antioxidant activity of isoflavone fractions.

• 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.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.101-101
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• 2020

Soybean is known as to have a several healthy ingredients. Among them, isoflavones are effective in reducing obesity, menopausal symptom. Isoflavones consist of 12 isomers, including Aglycon, Glucoside, Malonyl glucoside, Acetyl glucoside, and are usually found in soybean seeds. The content is determined by the sum of 12 isomers, and the content value difference between the varieties is huge. In this study, we investigated the agronomic traits, 12 isomer of isoflavone content and composition for 49 soybean germplasms. This germplasms were selected from the 23,000 germplasms with the highest total content of isoflavones possessed by the National Agrobiodiversity Center. Seed samples were cultivated in experimental field located in Jeonju City on April 04, 2019. Matured seeds were harvested and portions of each seed samples were oven-dried, pulverized, and analyzed for their isoflavone compositions using HPLC-DAD. The soybean samples showed distinction in their agronomic traits, isoflavone compositions and contents. The days to flowering ranged between 38 and 69 days while the days to maturity ranged between 103 and 156 days. The seed coat color of soybean germplasms was 24 in black, 10 in yellow, 2 in green, 5 in yellowish green, 4 in green with black spot, 4 in pale yellow. The germplasm with the highest total content of isoflavones was the IT178054(1257.61±7.98 ㎍/g), but the germplasms containing the largest number of isoflavone isomers were IT274592, IT275005, both germplasms had 11 isoflavone isomers excluding Malonyl glycitin. The largest source of Aglycon, the most easily absorbed isoflavone form in the human body, was IT274592(DZ: 8.83±0.30 ㎍/g, GL: 11.14±0.81 ㎍/g, GE: 8.16±0.26 ㎍/g), while only IT274592, IT275005, IT308619 contained all three components of Aglycon. In Principal Component Analysis(PCA), the first two principal components showed more than 3.5 Eigen value and accounted for 58.2% of variability. The total content value had strong relationship with Malonyl genistin content value. Acetyl isomers had strong relationship, but Malonyl isomers were only related to isomers except Malonyl glycitin. These results will help in research on soybean varieties to enhance isoflavone ingredients.

• Journal of Nutrition and Health
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• v.35 no.4
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• pp.409-413
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• 2002

The purpose of this study was to determine to which differences in the source of protein (soy vs casein) and of isoflavones in soy protein are responsible for differential effects of bone mineral density and bone mineral content. Thirty 21-d-old Sprague-Dawley young rats were divided into 3 groups: the control group was find a casein-based diet, the soy concentrate group was fed soy protein with totally reduced isoflavones content (isoflavone 0.07 mg/g protein), and soy isolate group was fed with a higher isoflavone content (isoflavone 3.4 mg/g protein) than normal. The animal was scanned to determine the BMD and BMC using dual energy X-ray absorptiometry (DEXA, Lunar Corporation, Madison, WI). The soy concentrate group had significantly higher total body calcium/weight and total mineral content/weight than the casein group. The soy isolate group had significantly greater total bone mineral density/weight, spine bone mineral density/weight, and femoral bone mineral density (in g/$\textrm{cm}^2$ than the control and soy concentrate group. The findings of this study suggest that soy protein and isoflavones in soy protein are beneficial for bone-formation in growing male rats. Therefore exposure to these soy protein and isoflavones early in life may have long-term health benefits for bone diseases such as osteoporosis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.242-252
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• 2022

Soybeans have various applications, and are a major source of proteins, carbohydrates, and fats. As climate warming has accelerated in recent years, this study was conducted to analyze the effect of different sowing periods on component changes in protein, amino acid, and antioxidant contents of various soybean varieties. The isoflavone content of soybeans that were sown early did not differ with the sowing period. Based on the results, only the total isoflavone content was confirmed in functional soybean cultivars such as Cheongja-5, which had blue-colored seeds; Pungsan and Sowon, which used soybean sprouts; and Jinyang, which lacked a fishy smell. There was no significant difference in the changes in protein and amino acid content in soybean cultivars with respect to the sowing time. The protein and amino acid contents in early-sown soybeans tended to be lower than that in timely sown soybeans. In most varieties, the content of proline was the highest in early-sown soybeans, confirming the presence of stress due to early sowing.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.4
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• pp.543-550
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• 2010

This study was conducted to determine the characteristics of chungkukjang with added isoflavone extracted from arrowroot and to determine its utility as a functional food substance. Crude isoflavone was prepared from arrowroot by the ethanol extraction method and frozen dried (AI). Samples of chungkukjang each had different amounts of isoflavone extracts added to them: 0 (control), 1.76 (AC1-chungkukjang), 3.52 (AC2-chungkukjang), and 7.11 (AC3-chungkukjang) g/kg. The pH, color, slime material content, calcium, and isoflavone of each sample were measured to investigate the quality and changes in isoflavone content. As AI increased, the pH of chungkukjang decreased to 7.46~7.53 compared to the pH of control (7.63). The slime material content range increased to 4.46~6.16%. However, there was no significant difference in the general components of chungkukjang between each of the groups (Con, AC1, AC2, AC3). In colors of chungkukjang, values for $L^*$, $a^*$, and $b^*$ decreased as AI increased. Meanwhile, the calcium content of AC1, AC2 and AC3 tended to increase by 11.18~12.82% compared to the control. This may be due to the influence of Ca in the arrowroot extract powder. There was a remarkable increase in total isoflavone content, by 30.81~130.66%, with an order of AC3>AC2>AC1. In all of the groups, the content of genistein and daidzein, aglycone form, increased dramatically, by 65.00~128.34%, and 89.38~142.91%, respectively, compared to the control. In AC3, in particular the genistin and daidzin content increased by 103.47% and 188.13%. These results showed that AI can be used as a source of isoflavone supplementation in chungkukjang.

• 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.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.444-450
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• 2007

The antioxidant activity and isoflavone content of chokong, Rhynchosia nolubilis seeds pickled in vinegar at $4^{\circ}C$ for 2 weeks, were investigated. The polyphenol content and 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical-scavenging capacity were lower in chokong than in raw seeds. Based on isoflavone analysis, the aglycone (daidzein and genistein) content was high in chokong while the content of the corresponding glucosides (daidzin and genistin) was similar to that in raw seeds. Thermal processing, in which seeds were heated in vinegar at $121^{\circ}C$ for 20 min, reduced the polyphenol content but did not affect the DPPH radical-scavenging capacity compared to the pickling process. The heated seeds had a 2.6 to 2.7 times higher glucoside content and 51 to 55% lower aglycone content than chokong, depending on the kind of vinegar used. During pickling and thermal processing, vinegars were more effective at eluting antioxidants and isoflavones from seeds than other solutions such as acetic acid, citric acid and HCl solutions, distilled water, and phosphate buffer (pH 7.0).