| MiZao jujube is kinds of rhamnaceae and belongs to ziziphus plants, it is main production area in Santai county of Sichuan province. It tasted crisp and tender and region fruit of high nutritional values. However, little has been reported on the product processing of MiZao jujube juice satisfy the market demands. In this paper, we use MiZao jujube as raw Smaterial to study the optimizing of process parameters and change in physicochemical properties and antioxidant activity during store. The main results are as follows:1. In the production of MiZao jujube juice, key technologies, such as color protection, blanching, clarification, product formulation, increase flavor and stablility tests were optimized by one-factor-at-a-time, assembly experiment and orthogonal array design methods. The optimal color protection formula (per 100 mL) was composed of citric acid 0.05 g, Vc 0.025 g and Na2SO3 0.025 g, the optimal blanching conditions were 95℃ and 3 min; the best clarification conditions were pectinase 0.12 g/100 mL, pH 4.5,45℃,2.5 h; the best beverage formula(per 100mL) compositions of MiZao jujube juice 40 mL, sucrose 5.0 g and citric acid 0.1 g; the best increase flavor formula (per 100mL) were added salt 0.03 g and honey 0.1 g; the optimal stability conditions formula (per 100 mL) was composed of CMC 0.1 g, maltodextrin 0.06 g and beta-cyclodextrin 0.06 g. Determination results of the physicochemical and microbiologic standards of finished products could meet the national standards.2. There were similarly changed except reducing sugar and total sugars when the MiZao jujube juice A and B of physicochemical properties during was stored under natural environment. During store,the turbidity, clarity and phosphorus havd not changed, others change as follows:pH and TSS had not obvious changed; chromatic aberration, precipitation rate, total acid and starch had increased trend; chromatic aberration and precipitation rate changed more than others; sugar-acid ratio, lpolypheols, Vc, total flaovonids, protein, tannin, calcium and iron had decreased trend; conductance increased first then decreased during stored. Change of variation of every indicator MiZao jujube juice A was less than B, so stablility of A was superior B during store. Excepted that the the conductivity, precipitation rate, tuibidity, the starch, total sugar and sugar-acid ratio assuming the visible differences between MiZao jujube juice A and B during storage, others indexs were no significant difference (P<0.05).3. Antioxidant capacity includes the reducing ability, the total antioxidant capacity, the ability of eliminating DPPH free radical, the ability of eliminating OH, the ability of eliminating NO2-, the ability of eliminating O2-. A compared study on antioxidant capacity was conducted among MiZao jujube juice, snow pear juice, grape juice, orange juice and wild jujube juice. The results were as follow:the reducing ability, total antioxidant capacity, eliminating capacity of NO2-,OH and ·O2- the type of MiZao jujube juice is stronger than others 4 juices. Excepted that the scavenging DPPH-capacity of MiZao jujube juice was weaker than orange juice, the capacity of total antioxidant chance of is still stronger others during attenuation. As the concentration reducing the 5 kinds juice assuming the visible differences the capacity total antioxidant, DPPH-free radical, but above were no significant difference the capacity of powering, scavenging·OH1·O2- and NO2-(P<0.05).4. The main antioxidants of MiZao jujube juice were determined through accelerated shelf life test and its in vitro antioxidant activities. The Q10 of MiZao jujube juice was 2.96. The scaveing capacity of DPPH-free-radical,·OH free radical,·O2- free-radical and NO2-maintained more than 90% and the inhibitory activity toward lipid preoxidation running into 62% during storage. The results showed that the max of the FRAP was 474.18 μmol/g of 0.08mL jujube juice when store to 5 months; the max the chelating ability of NO2- was 97.77% of 0.04mL jujube juice when store in 8 months; the man of free-radical scavenging capacity of ·DPPH was 97.38% of 0.04mL jujube juice when stored just started; the max of free-radical scavenging capacity of ·O2- was 97.78% of 0.04mL jujube juice when stored to 2 months; the max of free-radical scavenging capacity of ·OH was 99.74% of 0.04mL jujube juice when store to 8 mouths; the inhibitory activity toward lipid peroxidation max was 62.96% when store to 5 mouths.’MiZao’jujube juice were no significant difference the capacity of antioxidant during store(P<0.05). |
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