Optimization Of Fermentation Techniques For Grain Kvass

Kvass is a classic soft beverage made of bread, fruits or grains, which is fermented by lactic acid bacteria and yeasts. It is mellow and fresh as beer and cool as carbonated beverage. The traditional kvass production is made of black bread, the alcohol content less than 1%, and the color is similar to beer, brown-red. It is tasted fresh, sweet and sour moderate with a prominent bread flavor. However, due to the limitations of traditional production of materials and technology, industrial production is limited.In recent years, with the development of the beverage industry, there are already some scale of production kvass business, but bread is the most good brand categories rusks as the main raw material, and the styles vary greatly from different productions with traditional European kvass. So, it is full of practical significance to solute the problem with the typical flavor and the raw materials in industrial production.The material is the basis for the flavor characteristics of the product, the composition ratio of grain feedstock mashing process determines the composition of the extract. By experimentally derived kvass production of grain composition and proportion of raw materials:barley malt: burnt malt: black malt = 69: 30: 1.The most important part of the production of fermented products is microbial. Based on the screening single strain and complex microbial agents from three strains of Saccharomyces cerevisiae and five strains of lactic acid bacteria with analyzing the indicators of ethanol, total acid, growth conditions in the wort and organic acid species content, the Lactobacillus plaintarum and brewing yeast 1 were proved to be suitable for the fermentation of grain kvass.The method of Plackett-Burman design based on the results of one factor experiments was used to selected the important impact. The first three factors that had an important impact on Kvass qualities were selected from original wort concentration, fermentation time,temperature, inoculum concentration, proportion of lactic acid bacteria and yeast. Then, the Box-behnken design was used to further optimize the conditions. The finial determined conditions were as follows: original wort concentration of 6.5°Bx, fermentation time 23 h,fermentation temperature at 26.8℃, stain ratio of Lactobacillus plaintarum and brewing yeast2:1, inoculum concentration 3%. The concentration of alcohol and total acid of the Kvass sample under optimized production process were 0.85(%, v/v) and 4.0(g/L, lactic acid basis).The results show that we could produce kvass full with typical flavor by choosing grain material.