B-group vitamin and mineral contents of soybeans during kinema production

Concentrations of several B-group vitamins, determined by highperformance l iquid chromatography (HPLG), and minerals, determined by inductively couple d plasma atomic emission spectroscopy (ICP-AES) in soybeans during differen t kinema production stages were compared. After soaking soybeans in water, thiamine (B-1) content decreased, whereas riboflavin (B-2) content remained unchanged. Cooking had no influence on the B-1 content, but It enhanced th e level of B-2 and niacin (B-3). Incubation of beans at 37 degrees C for 48 h, when mixed with Bacillus subtilis, caused an increase in concentration of both B, and B-2. Vitamin B-1 levels decreased when either Enterococcus f aecium accompanied B subtilis or the temperature was elevated for 18 h ferm entation. Traditionally prepared kinema contained 8 mg B-1, 12 mg B-2, 45 m g B-3, 683 mg Ca, 4 mg Cu, 18 mg Fe, 494 mg Mg, 10 mg Mn, 1257 mg P, 2077 m g K, 13 mg Zn and <0.5 mg of Cd, Cr, Pb, Ni and Na per kg dry matter. While the vitamin B, content was significantly (P < 0.05) higher, the contents o f vitamins B, and Eb, were significantly (P < 0.05) lower in raw soybeans t han those in kinema. Mineral concentrations were 3.1-8.3 times higher in ra w soybeans than in kinema. (C) 1998 Society of Chemical Industry.