Study On Accelerated Fermentation Of Fish Sauce By Subsection

Fish sauce was an nutritional and health protection liquid condiment throughout fermentation.The Chinese traditional fish sauce needs too much more fermentation time,but the products with accelerrating fermentation had the bad flavor. This dissertation focused on improving the volatile flavor of fish sauce which produced with accelerrating fermentation.The effect of adding enzymes, adding Koji and keeping temperature fermentation for salted fishes on the volatile compounds of fish sauce by subsection were investigated. The enzyme accelerate hydrolyze of protein at the first stage of fermentation. In order for flavor forming,fish sauce fermented at room temperature or adding Koji at the middle stage, holding temperature processing at the last stage.Their optimum condition that hydrolysis salted fish conditions to with Alcalase2.4L and Papain in Saturated salt was narrowed than unsalted fish.The effect of hydrolysis fish sauce with salted fish was reduced by comparing with hydrolysis fish sauce with unsalted fish, the contents of TSN,AA-N was reduced to13.4%,37.9%;The flavor of hydrolysis fish sauce with salted fish was better than unsalted fish,more like tradition fish sauce,and low molecular weight volatile fatty acids have been identified as contributing to improve aroma of fish sauce,but the characteristic aroma of fish sauce have not been identified which was in possession of the flavor of mature tradition fish sauce after being fermented for some time.The accelerated ripeness of traditional fish sauce of latter fermentation by holding temperature processing were studied. The results suggested that TSN,AA-N increased in the accelerated ripeness with the increasing of temperature and time. After 8d with holding 60℃processing, the contents of TSN,AA-N was heightened to 42.2%,32.3%;The contents of volatile fatty acids,2-methylpropanal,2-methylbutanal,and dimethyltrisulfide increased by the analysis of HS combined with GC-MS.After 8d with holding 60℃processing,the volatile compounds and contents in accelerated fish sauce of 2 years fermentation reach to the levels of those in fish sauce of 3 years fermentation.The sample with methods of the three stages fermentation not only accelerate hydrolyze of protein at the first stage but also were very close to the odor of traditional fish sauce after the latter two stages the result of the sensory test. With adding Koji at the middle stage,it would increase continuedly the contents of TSN,AA-N, more been better for the tasted amino acids than amino acids of humans essential.Dimethyl trisulfide,3-methylbuten- al,2-methyl-butanoic acid of the major contributors to the characteristic odor of fish sauce were identified with the analysis of HS combined with GC-MS.So this method can shorten the fermentation time sharply and has less bad effect on flavor.