The Effects Of Different Koji And Fermentation Process To The Quality Of High Salt Diluted Soy Sauce

Soy sauce is a knid of traditional Chinese condiment, which has a history of about 2500 years. At present, the yield of soy sauce in China is about 600 ton every year, which is more than 60% of the total yield in the world. Japanese soy sauce was originated from Chinese soy sauce with the history of 300 years, but it is at the leading position in the international soy sauce market. The difference of the quality is the most important reason. In order to improve the competition ability of Chinese soy sauce in the international market, it is very urgent to improve the quality and level .In this paper, the difference in normal indices and volatile aroma was compared between Chinese and Japanese soy sauce in order to providing the reference to the improvement of high salt diluted soy sauce quality.The effects of exogenous additives and the pretreatment of raw material to the enzyme activity and fermentation was researched later,so as to set the fundmental to the raw material use ratio and quality improvement.The results show:(1) The difference of physicochemical properties and aroma are the primary reason for the quality discrepancy of Chinese soy sauce and Janpanese soy sauce. All the indices of Chinese soy sauce except sodium chloride concentration were lower than that of Japanese soy sauce. The content of reducing sugar, total nitrogen and amino nitrogen were lower than Japanese soy sauce by 15.Both the quantity and content are different between the Chinese soy sauce and Japanese soy sauce.125 kinds of aroma were detected in Japanese soy sauce,which is 31 kinds more than that of Chinaese soy sauce.(2) Adding the exogenous additives suitably and the pretreatment are the important measures in improving the enzyme activity.Different kinds of hydrolysis of soybean protein isolate have different effects to the enzyme activity.In which the hydrolysis of papain for 48 hours has a prominent effect to the enzyme acticity of koji, which can improve the acid protease activity by 46% to 744 u/g. The phytase and phospholipase which were added by 0.1%(w/w) and 0.5%(w/w) all can improve the acid protease by 15% and 6% respectively.Physical method was used to smashing soy bean,then the samching soy bean was used in koji, which had a prominent effect by improving the protease activity and the number of spore nearly 1.5 times.(3) The koji and fermentation process have prominent effect to the brewing and quality of soy sauce.Adding the hydrolysis of soybean protein isolate (the hydrolysis of papin for 48h) and smashing the raw materials in the koji process for fermentation, the total nitrogen, ammonia nitrogen, total acid, reducing sugar and solid content have definitely improved. The concentrations of sodium chloride have prominent effect to the brewing of sou sauce, ifferent concentrations of sodium chloride were used for brewing. The data shows that the lower the salt concentration was, the higher the total nitrogen, ammonia nitrogen and total acid content are, while with lower reducing sugar content.