Changes of Nutrition and Bacterial Diversity During Traditional Soypaste Fermentation

Abstract:

Nutrient dynamics and bacterial diversity of traditional soypaste were analyzed and discussed with samples from Shandong province by nutrition and denaturing gel gradient electrophoresis (DGGE) analysis. The nutrition value was determined by following parameters: total acid, water-soluble carbohydrate (WSC), organic carbon (OC), crude protein (CP), amino-acid nitrogen and volatile products. Results showed that the total acid was increased at first, and decreased, and then increased again up to 6.26%. The contents of OC and WSC remained decline. As for CP, it was decreased after increased stable. The amino-acid nitrogen was kept increasing during the whole progress and its concentration was up to 101.2 g/kg in final soypaste. The concentration of lactic acid and glycerol were increased during the fermentation, and were up to 5.65 g/kg and 14.72 g/kg in final soypaste, respectively. DGGE analysis indicated that there were the most kinds of bacteria in 15d soypaste, and then some of bacteria were disappeared gradually. Uncultured bacterium, Lactococcus lactis and Bacillus licheniformis of final soypaste were predominant species in final soypaste.

Key words:Traditional soypaste, Changes of nutrition, Bacterial diversity