Processing Technology Of Fermented Ziziphus Jujuba Zhanhua Juice Beverage By Probiotics

The amount of jujube in China is very large.The sale of fresh jujube is difficult because it has a short shelf life.The Chinese jujube rots more than 30%every year.The deep processing methods of jujube are very few.The dried jujube products account for about 70-80%.Furthermore,the fresh jujube processing method is very limited and there are few fermented juice drinks.Ziziphus jujuba Zhanhua is well-known for its juicy,sweet,rich soluble solids and high nutritional value.However,less research focused on deep processed products of Ziziphus jujuba Zhanhua.In the present study,jujube juice was obtained from Ziziphus jujuba Zhanhua.Lactobacillus plantarum,Lactobacillus casei and Lactobacillus paracasei were used as fermentation strains to develop a fermented jujube juice beverage.The research developed a new type of jujube beverage product,which improved the resource utilization rate of jujube,and provided theoretical basis and basic technological parameters for probiotic fermentation of the fruit juice beverage.This thesis was mainly aim to figure out the juicing process,fermentation process,post-fermentation preparation and preservation period inspection of the jujube juice beverage.The main results are as follows:1.Based on the single factor test results,the response surface method was used to optimize the enzymatic hydrolysis process of jujube juice.The addition ratio of pectinase and cellulase was determined to be 1:2.The effects of the enzyme amount,enzymatic hydrolysis time and enzymatic hydrolysis temperature on the juice yield and soluble solid content of jujube were studied.The results showed that the juice yield was 72.27%and the soluble solids content was 8.0%under the conditions of 0.1%compound enzyme,68 min hydrolysis time and 50°C hydrolysis temperature.2.Optimized the fermentation process of Zhanhua winter jujube juice by probiotics.By comparing the fermentation conditions of single and compound bacteria in jujube juice,it was determined that the Lactobacillus plantarum:Lactobacillus casei:Lactobacillus paracasei=1:1:1 was used as the fermentation strain.Based on the number of viable bacteria,pH,total acid and total sugar in the fermented jujube juice,the single-factor test and response surface test were used to optimize the fermentation conditions:inoculum size 3%,fermentation temperature 37°C,fermentation time 36 h,under these conditions,the viable count can reach 5.45×10~8 cfu/mL3.Study on the formulation and stability of fermented beverages.The sensory score was used as an indicator.The optimized result was 8%sucrose addition and 2%oligoisomaltose.According to the centrifugal sedimentation rate,the ratio of composite stabilizer was 0.15%sodium carboxymethyl cellulose,0.05%xanthan gum and 0.10%carrageenan.The stability of the winter jujube fermented beverage was good under these conditions.4.Study on the preservation period of winter jujube fermented beverages.The winter jujube beverages were stored at 4°C and stored at room temperature(20°C).The number of living bacterium in fermented jujube beverage were greater than 1×10~6 cfu/mL at room temperature after 8 days,but it tasted sour.It showed that the beverage can be saved for 6days at room temperature.The number of viable bacteria,pH and total acid content in different storage time were measured.The results showed that the pH of the beverage after 35days of storage at 4°C decreased,the total acid content increased,the number of viable bacteria were still greater than 1×10~8 cfu/mL,the taste was good,the sensory evaluation score was above 80 points.It indicated that the product can be preserved for 35 days under the condition of cold storage.