Analysis Of Microbe In Naturally Fermented Rice Cake And Application Of Its Dominant Strains

Fermented rice cake is a traditional fermented food, it is mostly produced in hand workshop, the producers use natural fermentation methods, fermentation liquid often breeds bacteria, the quality is unstable, the sanitation is difficult to guaranteed. So the production and quality assured. In this paper the representative naturally fermented rice cake and fermented rice slurry in the city of Changsha were studied by the traditional screening technology. The dominant strains in fermented rice slurry were analyzed and used to fermentation, while the process technology was optimized, and this would provide the theoretical support for making the fermented rice cake of good taste, stable quality, health and safety. The main results are as follows:1. Analyzed microbial of natural fermented rice slurry11fermented rice cake and fermented rice slurry samples were analyzed by traditional microbiological technology. The total bacteria counts, colony characteristic and individual form of different microorganisms were discovered, and found Lactobac-cillus and yeast were the dominant strains, the total bacteria counts was above107CFU/mL.2. Screened and identified the dominant strainsLactobacillus pantheris was separated, and tested for acid producing and growth ability, Saccharomyces cerevisiae was screened by sugar fermentation test and growth ability test They were identified by Morphology-and Molecular Biology, and showed excellent capacity of fermentation.3. Optimized process condition for fermented rice cake starterDeveloped mixed strains starter culture with Lactobacillus pantheris and Saccharomyces cerevisiae, and optimized fermentation conditions:temperature35℃, bacteria ratio1:1, solid-liquid ratio6:4, sugar6%, fermentation time12h. The count of lactic bacteria was9.2×108CFU/mL, yeast was8.1×107CFU/mL in starter culture.4. Optimized production process of fermented rice cakeWe optimized production process of the fermented rice cake by orthogonal test: solid-liquid ratio6:4, inoculum size12%, fermentation time3h. After the process have optimized, the fermented rice cake have rich and dense foam, the alcohol and acidity is suitable, white color, good texture, excellent taste flavor.5. Analyzed aroma components of fermented rice cake made by different processUsing GC-MC method, analyzed the aroma components of fermented rice cake produced by different process conditions. It showed that the mainly aroma components of fermented rice cake is alcohol, n-amylalcohol, Phenylethanol. Under optimized process condition, N-amyl alcohol is dominant by84.46%, and rice cake flavor is pure, without harmful substances. While under natural condtion and sold in market,the fermented rice cake both have aldehyde, acid, naphthalene and some other peculiar smell ingredients. Therefore, the fermented rice cake that produced by artificial inoculation can assure good quality and safety, and be easy for mass production.