Studuy On Ultra-high Pressure Processing Technology For Mulberry Juice And Storage Stability

The traditional thermal pasteurization processes are effective on sterilization of mulberry juice. However, they cause mulberry color deepened, heat-sensitive material losses, and changes in antioxidant activity etc. In order to produce high quality and antioxidant activity mulberry juice, and to ensure the safety of fruit juice, to evaluate the application of non-thermal processing technology on the processing of high-quality mulberry juice, inactivation of microbe,and effect on the quality of pear juice by UHP were investigated. The main contents are as follows:Process parameters of mulberry juice were optimized by the combination experiments, with mulberry juice yield indicators enzymatic. The results showed that the optimal parameters were as follows:the ratio of pectinase and cellulase enzymatic was 1:1.36, enzymolysis pH5.0, enzymolysis temperature 49.54?, enzymolysis time 2.63h, the juice yield was 86.41%.Consistent with the prediction vaule Ultra-high pressure electric field sterilization of the total number of colonies mulberry kill death ratio index, sterilization process parameters was optimized by response surface methodology analysis. The results showed that:pressure 483MPa, pressure holding time 25min and temperature 15?,it can well meet the national standard for mulberry juice hygiene.Analysis and comparison of ultra high pressure treatment and heat treatment mulberry juice changes in microbiological?quality?active ingredients. The results showed that:high pressure sterilization and heating sterilization can inactivation of microorganisms in mulberry juice and can achieve commercial sterility; compared with unsterilized mulberry juice, high pressure sterilization had a little effect on pH?soluble solids content?conductivity? browning degree; high pressure sterilization change to a lesser extent of the volatile flavor compounds, resveratrol composition, total phenols, lycopene, clearance of-OH and DPPH total antioxidant capacity, but heat treatment juice quality indicators change to a more extent, ultra high pressure treatment mulberry juice can more complete reserves the nutrition and antioxidant activity.Analysis and comparison of high pressure sterilization and thermal sterilization of mulberry juice storage stability at 4?,25? conditions, the following conclusions:storage 60 days later, the detection can achieve commercial sterility requirements juices, indicating that juice good sterilization effect; during storage, high pressure sterilization of juice growth in both pH,soluble solids content, conductivity, browning degree change not any, total phenols, clearance of DPPH, total antioxidant capacity had a little influence; thermal sterilization of mulberry juice was had obvious influence, during storage, three kinds of sterilization of mulberry juice resveratrol composition showed a downward trend, and high pressure treatment juice quality indicators change to a lesser extent; compared with the stored at room temperature, low temperature storage can inhibit color, shape, fragrance and taste of deterioration of mulberry juice, and high pressure sterilization is a good way to keep mulberry juice flavor, color, and other sensory quality than heat sterilization.