Preliminary Research Of Fermentation By Specified Microorganism For Abalone

Fermentation of abalone meat under some conditions alters certain biochemical indicators of it, this provide with useful parameters for abalone processing and storage. Proteases produced by microbes break down the protein in abalone meat into peptides and amino acids, which can be absorbed easily by human, hence abalone products are endowed with unique flavor and color. With improvement of people's living standard, abalone is favored as delicacy by more and more people. As disadvantages such as high water content of abalone etc, abalone products are easily off flavor during processing and storage later on, and devaluate itself greatly. The purpose of this dissertation is to study biochemical and microbial changes of abalone during its processing by applying specific fermentation. The primary task is to control changes of flavor of abalone during its drying process, and provide with necessary data for production.Experiments and results:1) Growth curves of three microbes, Aspergillus oryzae, Lactobacillus helveticus, pediococcus pentosaceus, in culture medium of abalone meat were examined, and the results show that Aspergillus oryzae grow well in abalone meat, and the two others show no obvious difference in growth rate.2) Production conditions of neutral protease by each species of microbes in abalone meatProduction conditions of neutral protease by the three microbes in abalone meat were studied. Under conditions of 45% water addition, inoculation quantity of 1.0×108 spores each gram medium, culture temperature of 30℃and culture time of 60 hours, Aspergillus oryzae produces 24.463U/g of neutral protease maximumly; Under conditions of 55% water addition, inoculation quantity of 1×107 spores each gram medium, culture temperature of 35℃and culture time of 48 hours, Lactobacillus helveticus produces 10.566U/g of neutral protease maximumly; Under conditions of 55% water addition, inoculation quantity of 1×108 spores each gram medium, culture temperature of 32℃and culture time of 48 hours, pediococcus pentosaceus produces 9.743U/g of neutral protease maximumly.3) Optimal production conditions of amino acid nitrogen when each species of the microbes is inoculated in abalone meatBy studying optimal production conditions of amino acid nitrogen when Aspergillus oryzae and Lactobacillus helveticus are inoculated respectively in abalone meat, following results are obtained:when Aspergillus oryzae is fermented 60 hrs under conditions of water addition of 70%, inoculation quantity of 0.5x108 spores each gram medium, culture temperature of 30℃, the content of amino acid nitrogen is 3.148%,3.7 times higher than that of unfermented control sample which is 0.849%, and is increased 55.23%compare to highest level in experiment of single factor, furthermore, the sequence of importance of factors is fermentation time, volume of water addition, temperature, inoculation quantity; when Lactobacillus helveticus is fermented 50 hrs under conditions of water addition of 55%, inoculation quantity of 0.5 X 107 spores each gram medium, culture temperature of 34℃, the content of amino acid nitrogen is 3.130%,3.6 times higher than that of unfermented control sample which is 0.849%, and is increased 32.46%compare to highest level in experiment of single factor, furthermore, the sequence of importance of factors is volume of water addition, fermentation time, temperature, inoculation quantity.Conclusion:Aspergillus oryzae is better in fermentation of abalone meat than Lactobacillus helveticus in terms of adaption to living environment, production of neutral protease and improvement of production of amino acid nitrogen.