Reduction of the biogenic amine contents in low salt-fermented soybean paste by gamma irradiation

Irradiation effects on biogenic amines of low salt-fermented soybean paste were investigated during fermentation at 25 °C for 12 weeks. Low salt-fermented soybean paste was prepared with 6% and 8% salt, and a 12% salted one was used as a control. The prepared fermented soybean pastes were irradiated with doses of 5, 10, and 15 kGy. Non-irradiated samples (6% and 8% salt) showed optimum pH to produce biogenic amines during fermentation. The biogenic amines detected were putrescine, cadaverine, β-phenylethylamine, spermidine, spermine, tryptamine, histamine, tyramine, and agmatine. Most biogenic amines, except β-phenylethylamine and tyramine, were significantly reduced by irradiation treatment during fermentation. Lower salt conditions produced more biogenic amines than higher ones. However, gamma irradiation of low salt-fermented soybean paste could reduce the biogenic amine contents during fermentation.