Status of traditional fermented soy food products: a future trend

Traditional fermented soy food products have become part of daily diet in Asian countries. The fermented process has been studied to improve quality, taste, flavor, aroma and nutritional values to expand the market to other continents. Both salted and non-salted soybean fermentation products were identified to eliminate wild microorganisms to improve quality and safety. The well-known salted soybean fermentation products are soy sauce, soy paste and fermented soy curd. Presently, soy sauce is the most recognized product in global market, which quality standards and safety have been under consideration from member countries of FAO/WHO Codex Commission. The non-salted soybean fermentation products have traditionally been produced and consumed in various parts of Asian continent, which the phenomenal practices found the uniqueness of similarities. Most products obtained from natural fermentation and became a cheap source of high protein-rich food in local diet. Several investigations were also found predominant microbial activities produced polypeptides and amino acids from soybean protein during fermentation. The products have the improvement of nutritional quality, which has been promoted for health benefit. However, there are some products still consuming in the regions where they originated. Only natto in Japan and tempe in Indonesia have gained popularity nationwide. The others, chongkuk-jang in Korea, dou-chi in China, kinema in Nepal, Bhutan and northeastern Himalayan regions of India and thau-nao in northern Thailand have still been assessed microbial diversity association with traditional fermentation practices in producing specific taste and flavor for their consumers. The future research and development should be able to standardize a fermentation process to have widely acceptable products.