Effects of oven-drying, roasting, and explosive puffing process on isoflavone distributions in soybeans

Modification of isoflavone profiles in a fermented soy food with almond powder

Isoflavone profiles of a fermented soy food, cheonggukjang, were modified using almond powder. Isoflavones were analyzed by high performance liquid chromatography (HPLC) with an ultraviolet detector. Malonyl derivatives of isoflavones decreased and aglycones of isoflavones increased in samples with almond powder for 48 h. As added, almond powder increased from 0%, 5%, and 10% (w/w), amounts of aglycones increased to 21.11%, 26.63%, and 32.45% for 48 h, respectively. β-Glucosidase activity in 5% and 10% almond added samples was significantly higher than samples without addition of almond (P < 0.05). The content of succinyl daidzin and succinyl genistin, new metabolites from isoflavones, in almond-added cheonggukjang was significantly lower than control samples, implying that β-glucosidase activity from almond affected negatively the formation of succinyl derivatives (P < 0.05). Principal component analysis (PCA) for isoflavone distribution showed that first principal component (PC1) and second principal component (PC2) expressed 64.78% and 22.26% of the data variability, respectively. Biotransformation of isoflavones in any fermented soy foods can be achieved using natural products containing high β-glucosidase activity such as almond.

PRACTICAL APPLICATION

The results of this study can help to modify the structural transformation of phytochemicals in any fermented soy foods using natural products. Adjusting the content of almond powder can achieve wanted profiles, for example, high aglycones content. Also, content of metabolites such as succinyl derivatives can be controlled using proper amounts of almond and fermentation time.

Ginsenoside composition and antiproliferative activities of explosively puffed ginseng (Panax ginseng C.A. Meyer)

The puffing process was evaluated as an alternative to the steaming process for producing a biologically more active ginseng product, like red ginseng, from raw ginseng. A puffing treatment of dried raw ginseng roots induced an overall increase in crude saponin content. As puffing pressure increased, the content of ginsenoside Re, Rg1, Rb1, Rc, and Rb2 decreased, while ginsenoside Rg3 increased significantly as compared to raw ginseng. The content of ginsenoside Rg3 in puffed ginseng at a pressure of 490 kPa was similar to that of red ginseng. Cancer cell lines (HeLa, MCF-7, and HepG2) showed that antiproliferative effects of saponin extract of puffed ginseng increased with an increase in puffing pressure. Ginseng explosively puffed at 490 kPa had similar saponin constituents and antiproliferative effects as those of red ginseng.

PRACTICAL APPLICATION

The puffing process could provide an alternative mean to produce functional ginseng products, along with a reduction in processing time as compared to traditional red ginseng processing by steam.

Formation of succinyl genistin and succinyl daidzin by Bacillus species

6''-O-Succinyl-4'-hydroxyisoflavone-7-O-beta-D-glucopyranoside (succinyl-beta-daidzin) and 6''-O-succinyl-6,4'-dihydroxyisoflavone-7-O-beta-D-glucopyranoside (succinyl-beta-genistin), 2 new isoflavone metabolites, are found in cheonggukjang or natto, traditional soy-based foods fermented with Bacillus species. Standard isoflavones including daidzin, genistin, daidzein, and genistein, and mixtures of isoflavones extracted from roasted soybeans were added to the medium growing Bacillus subtilis or B. subtilis natto and formation of succinyl-beta-daidzin and succinyl-beta-genistin were monitored by high-performance liquid chromatography (HPLC). Samples containing Bacillus with daidzin and genistin produced succinyl-beta-daidzin and succinyl-beta-genistin, respectively, while those with daidzein and genistein did not produce succinyl derivatives. Daidzin in samples with B. subtilis and B. subtilis natto decreased by 39.7% and 10.7%, respectively, for 4 h incubation while genistin decreased by 66.8% and 17.6%, respectively. Genistein decreased faster than daidzein during incubation with B. subtilis or B. subtilis natto without formation of succinyl derivatives. In the case of mixture of isoflavones, succinyl derivatives increased and beta-glucosides and aglycones of isoflavones decreased significantly for 8 h incubation (P < 0.05).