Content composition and antioxidant activity of isoflavones in commercial and homemade soymilk and tofu

School of Kinesiology and Nutritional Science, California State University, Los Angeles, CA 90032, USA
Journal of the Science of Food and Agriculture (Impact Factor: 1.88). 11/2007; 87(15):2844 - 2852. DOI: 10.1002/jsfa.3041

ABSTRACT BACKGROUND: Isoflavones, found in soymilk and tofu, are one of the phytochemicals in soy-based products that may promote good health. Homemade tofu and various homemade soymilk samples were made using different soaking, grinding, and cooking methods. The homemade samples were compared to commercial tofu and soymilk for total isoflavone content and composition as well as their antioxidant capacity. All samples were freeze-dried and extracted with a 58% acetonitrile solution which was subsequently used to determine the isoflavone content by reverse-phase high-performance liquid chromatography. The antioxidant activity of extracts was determined using a modified 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) method and total antioxidant capacity was reported as ascorbic acid equivalents.RESULTS: The total isoflavone, aglycone, and antioxidant levels were significantly higher in homemade soymilk and tofu (1571 µg) than in commercial samples. Homemade soymilk made by the extended boiling method yielded the highest total isoflavone (2567 µg) and glucoside (1525 µg) content. A strong positive correlation was observed between the total isoflavone, aglycone conjugates, and genistein series concentration and antioxidant capacity of soymilk.CONCLUSION: Increased moist heating time yielded the highest concentration of total isoflavones as well as aglycone conjugates and the genistein series. Increasing the duration of boiling can increase the isoflavone content of both homemade and commercial soymilk and tofu. Copyright © 2007 Society of Chemical Industry

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Whole-bean soymilk has been prepared by using media milling. Some characteristics of media-milled soymilk have been determined and compared with filtered soymilk (similar to commercial one) and the whole-bean soymilk prepared by blending. There existed particles in nano/submicron scale in both media-milled and filtered soymilk. The particles in blended soymilk were greater than 1μm. Media-milled soymilk was the most stable among three samples, even after autoclaving. Solid recovery (98.44 ± 0.16%), viscosity (160.59 ± 4.26 cps), dietary fiber (22.68 ± 0.97% on dry basis), total polyphenol recovery (95.15 ± 7.09%) and isoflavone content (4.42 ± 0.03 mg/g dry solid) of media-milled sample were greater than those of filtered one. Aglycones, the most bioactive form of isoflavone, in autoclaved media-milled soymilk were more than 2 folds of those in autoclaved filtered soymilk. As no okara generated, the media-milling was an environmental friendly process.
    Journal of Agricultural and Food Chemistry 12/2013; · 3.11 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Major ginsenosides in ginseng (Panax ginseng) and its products are highly glycosylated, hence poorly absorbed in the gastrointestinal tract. β-Glycosidase-assisted deglycosylation of pure ginsenosides was peformed to study bioconversion mechanisms. Ginsenoside standard compounds, crude saponin, and red ginseng extracts were incubated with β-glycosidase (0.05% w/v, 55°C). β-Glycosidase has a broad specificity for β-glycosidic bonds, hydrolyzing the β-(1→6), α-(1→6), and α-(1→2) glycosidic linkages. The final metabolite of protopanaxadiol ginsenosides was Rg3 while the metabolite of protopanaxatriol ginsenosides was Rh1. β-Glycosidase treatment of red ginseng extracts resulted in a decrease in the amounts of Rb1, Rc, Re, and Rg2 after 24 h, whereas levels of the less glycosylated Rd, Rb1, Rg, Rg3, Rg1, and Rh1 forms increased. When crude saponin was incubated with β-glycosidase for 24 h, levels of Rb1, Rc, Re, and Rg1 decreased while levels of Rd, Rg3, and Rh1 increased as deglycosylated ginsenosides.
    Food science and biotechnology 12/2013; · 0.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim was to study the relationship between the isoflavone content in different soybean cultivars and in the soymilk. Seven cultivars of soybean seeds from two locations with different levels of isoflavones were processed to soymilk. The content of total and individual isoflavones was determined by high performance liquid chromatography. The total phenolic content, oil and protein content in soybean cultivars were also determined. Significant differences in the content of individual isoflavones were observed within the soybean cultivars. The strong positive correlations were observed between total isoflavone content in soybean seeds and in soymilk. The total phenolic content in soybean cultivars ranged from 83 to 143.4 mg GAE/100g of soybean. The total isoflavone content in soybean seeds ranged from 71.2 to 133.8 mg/100g of soybean which comprise from 76.7 to 98.8% of the total phenols. In soymilks, total isoflavone content ranged from 16.1 to 61.0 mg/kg of soymilk. The most abundant isoflavone in soybean seeds was genistein while in soymilk it was genistin. There was statistically significant difference (p < 0.05) among two locations in total and individual isoflavone contents.

Preview (3 Sources)

1 Download
Available from