Irradiation effects on biogenic amines in Korean fermented soybean paste during fermentation

Irradiation effects on biogenic amines (BAs) and microbiological populations of Korean fermented soybean paste were investigated during fermentation. Soybean paste was prepared and irradiated with doses of 5, 10, and 15 kGy, and then fermented at 25 degreesC for 12 wk. Bacillus spp. and lactic-acid bacteria decreased by irradiation but increased during fermentation. Biogenic amines detected were putrescine, cadaverine, P-phenylethylamine, spermidine, spermine, tryptamine, histamine, tyramine, and agmatine. A significant difference was not observed in BA content between control and irradiated samples immediately after gamma irradiation. However, 4 kinds of BAs, putrescine, tryptamine, spermidine, and histamine, showed significant reduction by irradiation during fermentation (P < 0.05).