Regulation And Control Of VC In Apple Juice Processing

Because of lengthiness of processing, heat damage, serious oxidation, degradation of quality in the current processing of apple juice, especially low retention rate of VC and other nutrient substance, base on the analysis of VC degradation pathway and condition, and by tracking the change of VC in each main current processing of apple juice. Main operation, mechanism and weight function that lead to VC loss were analyzed and confirmed. Based on it, product planning and market positioning of apple juice with high VC content was proposed. The core content to guarantee quality, including active regulation the quality of raw material, simplification of manufacturing procedure, creation of materiel environment with low oxygen, alleviate the degradation of quality at high temperature, were mainly studied. Effectiveness and feasibility of quality safeguard measure were evaluated and predicted. Finally, technological processes were initially conformed for apple juice with high VC content.In the simulation of the core process of the current apple juice and tracing detection of VC, it was found that drastic aeration and enzyme catalysis for AA lead retention rate of VC and AA in product reducing to32.36%and9.84%. Among the processing, the loss of VC and AA in broken process were the highest(lead retention rate were45.64%and80.05%respectively), which means aerobic degradation were the main reason of VC loss in the previous process, and high-temperature and tedious processing made the further hydrolysis of DHA down to finally use up in later processing.In the quality-assurance measures procedure of raw material change to product, it was found that low-temperature stress could obviously increase VC content for precocious and serotinous apple before saltus. Liao Fu apple and Gala apple postharvest in5d were frozen at-7±1℃4h and9h, contents of total ascorbic acid, AA, DHA increased by21.94%、24.90%,5.46%and20.17%,21.82%,12.12%; compared with the apples without cold treatment, contents of total ascorbic acid, AA and DHA of ’Ralls’ and ’Fuji’ which postharvest in30d increased about26.65%,28.93%,18.26%and15.78%,17.33%,11.30%; contents of soluble sugar, malic acid and Sugar-acid ratio declined about12.03%,7.54%,5.92%and14.53%,10.00%,5.04%respectively; aroma substance increased6and5kinds.VC loss could effectively decrease in low oxygen environment. When O2content was lower than2%in environment of N2,the loss ratio of total VC was4.64%in broking processing. Retention rate of total VC were relatively higher after sterilization of ultrahigh pressure by low temperature, and it reached to93.53%at550MPa and20±2℃for15min.Technological processes were initially conformed for apple juice with high VC content.include of raw material clean, low temperature stress, the adjustment of state, gas shielded crushing, gas separation, coarse filtration, grinding, filling and ultra-high pressure processing composition in low temperature successively. It was found when the ’Gala’ apple which postharvest in30d after processing at-7±2℃for20h, VC retention rate of high-VC apple juice could reach106.75%; For direct carry on the processing of raw materials, final VC retention rate of high VC apple juice could reach88.07%...