Produtos fermentados a base de soja (Glycine max): fermentação láctica e em estado semissólido.

Abstract

In the current market there is a growing consumer demand for healthy and diversified products. The society is more aware of the benefits of fermented foods, including those based on soy. The solid state fermentation has gained attention again due to higher income in obtaining products. In this work we analyzed the production strategies of fermented products having as substrate soybeans and soy milk. Yogurt was produced from the lactic fermentation of soy milk with the bacterial flora obtained from natural yogurt (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) for about 6 hours at room temperature. Hydrated and crushed soybeans were used as a medium for semisolid fermentation by Penicillium roqueforti. The medium with the inoculum was stored in seven plastic bags under microaerophilic conditions for 7 days at 30±5 °C. In the production of yoghurt was observed during fermentation a pH reduction from 7.6 to 5.0 and the Brix from 12 to 8.2, indicating sugar consumption and lactic acid production. The values of productivity, conversion factor of substrate to product and yield were 157.44 gL-1.h-1, 0.984 g/g and 96%, respectively. In solid state fermentation, the largest growth of P. roqueforti occurred in medium containing only the soybeans crushed and hydrated. The salt added in the medium acted as an inhibitor. Success was achieved in both cases, since there was microbial growth resulting from the consumption of the substrate.