Study On The Processing Technology Of Jujube Powdered

In this study, the jujubes were processed into jujubes powder through a series of treatment. The shelf life can be prolong effectively and retain main nutritional components and flavor, it can be added into other foodstuff, which enlarges application range of jujubes. Beach jujube of northern Shaanxi was chosen as raw material, the extracting process of jujube juice and preparation technology of jujube pulp was discussed, and proper fabricating process of jujube powder was chosen based on the drying process of jujube powder. Moreover, The hygroscopic, packaging material, quality stability and sanitary index of jujube powder were investigated. The main results and conclusions were as follows:(1) The extracting process of jujube juice: the content of soluble solids or the extraction rate of total sugar of jujube juice was taken as index for the investigation. Four extracting process of jujube juice were studied. Comprehensive analyse showed that ultrasonic-assisted the pectin compound enzyme extracted jujube juice can gain the best effect. The optimum conditions were enzyme concentration 320μL/g,water 5mL/g,ultrasonic power 125W, extraction temperature 35℃, ultrasonic time 20min. The extraction rate of soluble solids was 73.35%.(2) The preparation technology of jujube pulp: firstly, three soften treatment jujube methods by microwave were studied. Among them, heat water dip-microwave softening process of jujube had comparatively better effect, and the optimum conditions were as follow: hot water treatment 1h with 40℃, microwave power 540W, microwave time 90s, water 8mL/g. Secondly, the enzymolysis technology of jujube pulp was pectic enzyme 360μL/g, enzymolysis time 1h, enzymolysis temperature 40℃. Under above conditions, the viscosity of jujube juice decreased significantly and water holding capacity increased significantly.(3) The drying process of jujube power: through the drying process experiment of jujube powder, the best process method of jujube powder from jujube pulp was microware drying, and the optimum conditions were as follow: total solid content of jujube pulp was 40%, main drying adjuvant was maltodextrin, the ratio of solid matter of jujube powder and drying adjuvant 4:6, material thickness 5mm, microware power 360W, intermittent heating 10s/60s. The formula of composite drying adjuvant(main drying adjuvant quality percentage)was:β-cyclodextrin 15.0%, soybean protein isolate 2.5%, soluble starch 13.0%, lecithin 3.0%.(4) Study on moisture absorption characteristics and packaging materials of jujube power: firstly, the critical relative humidity of jujube powder by vacuum freeze-drying and microware drying were 29.8%, 37.8% and 54.6%, respectively. Using jujube powder by microware drying as material, foil plastic bag, PVDC and 0.25mm PE with moisture resistant agent were used to package jujube power. The results showed that after storing the jujube powder for 180 days at room temperature, the flavor and taste of product was still good, all packaging mentioned above could satisfy moisture proof effect.(5) Study on quality stability and sanitary index of jujube power: Using Jujube powder by microware drying as material, the coagulability was improved by adding proper anticoagulant, and determined xanthan gum as the best anticoagulant, the optimal addition in jujube power of jujube juice and pulp were 0.1% and 0.3%, respectively. At the same time, the sanitary index was measured, the results showed that the sanitary index of jujube powder by microware drying accord with state standard.