Abstract:

To prepare a fermentation broth rich in 1-deoxynojimycin (DNJ) available for the development of hypoglycemic functional foods containing DNJ using soybean dregs, a low-cost byproduct of agricultural products processing, as fermentation substrate and Bacillus subtilis B2 as fermentation strain, some fermentation conditions were optimized. The results indicated that the effect of inoculum size on the α-glucosidase inhibitory activity of fermentation broth was not significant. An inoculum size above 104 CFU/mL resulted in a α-glucosidase inhibitory activity above 20. However, fermentation substrate concentration, medium initial pH and fermentation temperature and time had substantial effect on the α -glucosidase inhibitory activity of fermentation broth. After fermentation for 48 h under the conditions of fermentation substrate concentration 30 mg/mL, medium initial pH 6－8 and 40 ℃, a maximum α-glucosidase inhibitory activity was obtained.

Key words: 1-deoxynojimycin, Bacillus subtilis B2, soybean dregs, hypoglycemic function, functional food