Isolation,Identification and Fermentation Process Optimization of Probiotics for Pumpkin Juice

In this experiment,the Cucurbita moschata Duch. was used as the fermentation raw material,and the strains were selected from the traditional fermented pickles in Daixian of Shanxi Province. Yeast which fermented pumpkin juice was selected by flat-panel screening and sensory evaluation. The yeast was identified as Debaryomyces hanseniiand besed on 18S rDNA sequences and Neighbor-Joining tree(NJ).The tolerance of the artificial gastrointestinal fluid cultured strain was measured,and the strain was found to be well tolerated and survival rate could reach 78.48%. By combined the fermentation process with single factor and the Box-Behnken experiment,it was found that the effects of various factors on process optimization were different,among which the amount of yeast,pumpkin concentration,sugar added,fermentation time were the main influencing factor. The best technology was 15.0% of the bacteria,7.7% of sugar,58 hours of fermentation time,39.0% of pumpkin concentration,32℃ of fermentation temperature,110℃ of sterilization for 20 min,the sensory score was 91.68,a difference of 0.37% from the predicted value. The results showed that the strains had excellent ability to ferment pumpkin juice,which could provide a theoretical basis for the fermented pumpkin industry.