Study On Optimization And Function Of Black Rice Jujube Drink By Lactic Acid Fermentation

Jujube is the unique and first popular dried fruit in China and has excellent nutritional and medicinal value.Black rice is known as "blood waxy",which centralized the function of color,smell,taste,nutrition and medicine.Currently,there are many products of jujube and black rice,but we almost can not find any fermented beverages combined jujube and black rice.In this study,we focused on production process optimization of black rice jujube lactic acid bacteria fermented beverage,and studied its functionality.The main contents and results were described as follows:The optimum levels of each test factor were determined by single factor experiments.Black rice and water ratio was 1:10 in liquefaction and saccharification.Furthermore,the ratio of jujube and black rice should be 1: 1 in lactic acid fermentation.The test is the single factor experiment,response surface level factors by Design-Expert 8.05 response surface design,black rice jujube lactic acid beverage acidity and sensory evaluation as an index to determine the solid-liquid ratio was 1:10,the ratio of red dates and black rice cereal is 1 : 1,the optimum fermentation is fermentation temperature 37.27 ?,fermentation time 27.31 h,inoculation 4.80%.Under these conditions,fermentation of beverage acidity 0.53 mol / L,bright color,soft texture,rich flavor and rich nutrition.This study compared the natural sedimentation,centrifugation,filtration and clarification of three clarification,we found that the chitosan clarification was the best.Based on single factor experiment designed response surface experimental by Design-Expert 8.05,the results showed that the optimum chitosan clarification black rice jujube beverage was temperature 70.43 ?,holding time 122.2 min,chitosan amount of9.13 g / L.With this condition clarification black rice jujube beverage transmission rate of up to 89.2%.In this study,the total flavonoids and the total polyphenol content of black rice jujube lactic acid bacteria fermented beverage were determined by NaNO₂-Al?NO₃?₃-NaOH colorimetry and Folin phenol reagent colorimetric.The results show that the total content of flavonoids was 0.71 ?g / mL,the total polyphenol content was 0.56 ?g / mL.In 1mg / mL Vc solution for the control,measurement and comparison of the black rice jujube DPPHfree radical scavenging ability of lactic acid drinks,total antioxidant capacity,the ability to clear the ABTS · + radical and free radical scavenging capacity,and the results showed that black rice jujube lactic acid fermented beverage has strong antioxidant capacity.