Isoflavone Contents in Germinated Soybean Seeds

Abstract

The effect of germination on isoflavone contents in two soybean varieties (Hutcheson and Caviness) was investigated. Soybean seeds were soaked at 25 degrees C for 12 h, germinated at 40 degrees C, and freeze-dried. The isoflavone contents of dry, soaked, germinated (hypocotyl length at 0.5, 2.5, and 6.5 mm), and nongerminated seeds were determined by high performance liquid chromatography. The maximum amount of total isoflavone, genistein, and daidzein with their beta-glucoside conjugates was obtained when hypocotyl length of the germinated-seed from var. Hutcheson was 0.5 mm (2.491, 1.500, and 0.671 mg/g), and from var. Caviness was 2.5 mm (2.78, 1.523, and 0.905 mg/g). A dramatic increase in malonylgenistin and malonyldaidzin (1.305 mg/g and 0.476 mg/g in Hutcheson, and 1.308 mg/g and 0.677 mg/g in Caviness, respectively) was observed at these hypocotyl lengths. A decrease was observed after this stage. Genistein and daidzein contents were highest just after soaking. Glycitein and its beta-glucoside conjugates remained almost the same during germination. Controlled germination can be used to enhance isoflavone content in soybean seed.

Nutritional and microbiological quality of germinated soy flour

“…Germination is a complex metabolic process during which the lipids, carbohydrates, and storage proteins within the seed are broken down in order to obtain the energy and amino acids necessary for the plant's development (Jachmanian et al,1995). Non germinated soybean grains contain some anti-nutritional and toxic compound which inhibit enzyme (Egounlety and Aworh, 2003;Ahia, 2003) and germination could help to overcome these disadvantages (Zhu et al, 2005). Germination process (Freed and Ryan, 1978) and heat treatment (Leontowicz et al 1998) reduced trypsin inhibitor in sprouted soybean (Zhu et al, 2005).…”

“…Non germinated soybean grains contain some anti-nutritional and toxic compound which inhibit enzyme (Egounlety and Aworh, 2003;Ahia, 2003) and germination could help to overcome these disadvantages (Zhu et al, 2005). Germination process (Freed and Ryan, 1978) and heat treatment (Leontowicz et al 1998) reduced trypsin inhibitor in sprouted soybean (Zhu et al, 2005).…”

Selection of Useful Germplasm Based on the Variation Analysis of Growth and Seed Quality of Soybean Germplasms Grown at Two Different Latitudes

“…Moreover, it was well known that isoflavone-rich diets are associated with antitumor effect (Coward et al 1993), improving effect in cognitive function (Zhao and Brinton 2007), effect on menopausal symptoms (Jou et al 2008), and bone-sparing effects (Ishimi 2009). In soybeans, isoflavones are present as aglycones and glycosides: soy isoflavone glycosides are 3 glycosides (daidzin, genistin, glycitin), 3 malonylated glycosides (6"-O-Malonyl daidzin, 6"-0-Malonyl genistin, 6"-O-Malonyl glycitin), and 3 acetylated glycosides (6"-O-Acetyl daidzin, 6"-O-Acetyl genistin, 6"-0-Acetyl glycitin) while its aglycones are called daidzein, genistein, and glycitein, respectively (Kudou et al 1991;Zhu et al 2005).…”

Phytoestrogens in foods on the Nordic market

“…Kim et al (2004) reported that the maximum was 20-50% above background levels (the increase was mainly in aglycones) and levels were back at background levels three days after initiation of germination. Zhu et al (2005), in contrast, concluded that the maximum was reached when the hypocotyl length of the germinated seed was tiny (0.5-3.0 mm, dependent on soybean variety). The latter authors also reported that the most prominent increase was seen for malonylgenistin and malonyldaidzin (2-3 times).…”