To Clarify The Type Of Date Juice Process Optimization And Its Stability Study

The optimized extraction and clarified technology conditions of jujube juice were studied, and its stability was investigated during the processing and storage.The jujube- ginger and jujube-astragalus compound beverage were developed.The content of this article consisted of six charpters,and the author's work are in the following five aspects.1.Orthogonal experiments based on single factor experiments were performed and the results showed that the optimal conditions of extraction by enzymatic hydrolysis as follows: 0.03%of enzyme concentration,3h of operating time and 50℃of enzymatic hydrolysis temperature.The pectinase clarification,chitosan clarification and adsorbing-clarification by macroporous adsorbent resin were performed to clarify the jujube juice.The optimal conditions for pectinase clarification were:the concentration of enzyme was 0.06%, enzymatic hydrolysis time and temperature was 1.3h and 55℃respectively.The jujube juice temperature was 40℃,6.34%of chitosan dosage,4.5 of pH for chitosan clarification and the optimum flow rate was 1ml/min for adsorbing-clarification.2.The effect of centrifugation,clarification and adsorbing by macroporous adsorbent resin on jujube juice were investigated.The results showed that the soluble solids content and light transmittance are nearly unchanged;pH value of jujube juice decreased somewhat during pectinase clarification;the adsorbing by macroporous adsorbent resin increased the color value to the largest extent;Vc content showed downtrend during the procession.3.The storage stability of clarified jujube juice was investagated at 4℃,20℃,35℃respectively.The results showed that soluble solids content and light transmittance remain stable at different temperatures.However,the Vc content,protein content of clarified jujube juice decreased a lot at the first 20 days.Low temperature storage is a prefered method which had the least influence on jujube juice.4.The thermal degradation kinetics of Vitamin C in the clarified jujube juice was investigated,and a mathematical model was established.The results showed that the loss of Vitamin C mainly caused by AA oxidation.A reversible first order model described well the AA degradation data.The conversion of DHAA into DKGA during thermal processing is inreversible.The vitamin C in jujube juice is more sensitive to heat than its in other fruit juices,this indicates that the thermal processing should be avoid during the procession and cold preservation is recommended to keep its stability.5.The jujube-ginger and jujube-astragalus compound beverage with good sensory quality were developed.