Development Of Low-alcohol Cider Fermented By Yeast And Lactic Acid Bacteria

Cider is welcome by more and more people because of its high nutritional value and health benefits, low-alcohol cider and beverages is going to be one direction of cider. This study is designed to screen out brewing yeast and lactic acid bacteria strain to make cider and to obtain the best process of low alcohol and flavor increasing cider using response surface method(RSM) through single factor test. Then study on the physical and chemical properties of cider. Based on the current research status domestically, this study isolate the yeast and lactic acid bacteria that can be used to brew cider from naturally fermented fruit, combined with sensory evaluation and preliminary fermentation tests to determine the most suitable fermentation strains; in response to sensory evaluation value to inoculation, fermentation time and fermentation temperature factors to determine the best cider fermentation process; next to analyze the physical and chemical indicators using best cider brewing process, to lay the foundation for future study.(1)The study screens out ethanol weaker strain of yeast and lactic acid bacteria from fruit natural fermentation broth. After morphological identification of yeast and cell morphology and colony characteristics observation, 26 S rDNA sequence analysis, ultimately identify WY007 as Pichia kluyveri, known as Pichia kluyveri WY007.(2)In this study, response surface analysis is used to establish yeast inoculation, lactic acid bacteria inoculation, fermentation time, fermentation temperature cider four factors affect the sensory quality of the best quadratic polynomial mathematical model, optimal brewing process were as follows: yeast inoculation is 5.2%(v/v), lactic acid bacteria inoculation is 7%(v/v), fermentation time is five days, the fermentation temperature is 27℃, the theoretical value of 93 points sensory evaluation, verification test results for 92 points, the analysis of theoretical and actual score is not significantly different(p<0.05), the optimization model is successfully established.(3) After fermentation obtained with the use of a single yeast WY007 cider ferment cider under optimum conditions the product’s physical and chemical parameters are evaluated. The latter ratio of alcohol obtained from the fermentation of yeast and lactic acid bacteria together with low alcohol products, the screen may also metabolize lactic acid bacteria to produce ethanol; double strain mixed fermentation of total sugar and reducing sugar content is lower than the single yeast fermentation, taste not sosweet; the lactic acid fermentation process in wine there is malolacticfermentation(MLF) process, will be part of malic acid(dibasic acid) into lactic acid(mono acid), so the total acid bacteria mixed double fermentation content will have a certain degree of reduction, soft index is higher, which is the role of cider taste improvement.