Study On Freshness Of Walnut Male Anthotaxy By Ultra-high Pressure Treatment

Walnut male anthotaxy is very rich in nutrition, and has a certain health functions,after pollinated, it can be picked as food, it has strong palatability, when afterprocessed, and it tasted tender, crisp, pure, palatability and has a distinctive flavour.Generally, after walnut male anthotaxy picked, it was dried and preserved for futureconsumption, but this approach often makes serious loss of nutrients in the walnutmale anthotaxy, and the picking period and shelf life of the male anthotaxy is veryshort. So most walnut male anthotaxy resources was wasted.In this study, Walnut male anthotaxy was used as raw material. The main contentsand results of the study were as follows:1. Study on blanch and color-protection treatment of walnut male anthotaxyIn the study of blanch treatment of walnut male anthotaxy, By single factor, suchas blanch temperature,blanching time and pH of blanching solution, influence oncontent of Vc, peroxidase activity and sensory characteristics of walnut male anthotaxy,On this basis, By orthogonal test design, As an indicator of the sensory characteristicsof walnut male anthotaxy after blanched, Determined the optimum processingconditions:blanching temperature was90℃, blanching time was60s, pH of blanchingsolution was5.5. After verification experiment, under this condition, the peroxidaseenzyme activity could be maximize passivated, but also made the content of Vc andsensory characteristics reached a certain expectation.Study on color-protection of walnut male anthotaxy after blanched treatment.Color-protection experiment was by Zn²⁺,citric acid,soaking time, soaking temperatureas influence factors, though orthogonal text design, As an indicator of color gradingand content of chlorophyll, Determined the best conditions for color-protection:concentration of Zn²⁺was350μg/mL, amount of citric acid was400μg/mL,soakingtime was30min, soaking temperature was50℃.2. Study of combined temperature and ultra-high pressure treatment onsterilization of walnut male anthotaxyIn this experiment, by ultra-high pressure treatment for walnut male anthotaxysterilization. Effect of ultra-high pressure, processing time and processing temperatureon the microorganisms of walnut male anthotaxy was studied. On this basis, throughthe orthogonal text design and analysis of results, after verificated and draw the following conclusions: treatment pressure was450MPa,processing time30min,temperature was45℃, Under this conditions, effect of sterilization was best.The preservation test after ultra-high pressure treatment, select three differentconditions with different pressure,time and temperature on walnut male anthotaxyprocessing, and then placed in37℃and preserved35d. Every7d, observe and testtotal bacterial count and growth of coliform. The conclusion was confirmed that higherprocessing pressure450MPa,processing time30min and temperature45℃, it couldeffectively extend the preservation period of the walnut male anthotaxy.3. Effect of ultra-high pressure treatment on freshness of walnut male anthotaxyIn this experiment, Using ultra-high pressure treatment on walnut male anthotaxy,effect of different pressure,time and temperature conditions on peroxidase andpolyphenol oxidase, chlorophyll, vitamin C and soluble protein of walnut maleanthotaxy was studied, on this basis, determined the Optimal conditions by orthogonaltest design: processing pressure was450MPa, processing time was30min, processingtemperature was35℃. Through verification test, the activity of peroxidase andpolyphenol oxidase had decreased to31.06%,29.17%, and content of chlorophyll0.409mg/g, retention rate of Vc89.64%, the content of soluble protein13.14mg/g. Thiscondition was proved reasonable and suitable to treat walnut male anthotaxy.4. Quality changes of ultra-high pressure treatment and heat treatment on walnutmale anthotaxy during storageBy heat treatment, ultra-high pressure treatment and heat combined withultra-high pressure treatment, this three different ways to treat walnut male anthotaxy,and study the changes of quality and microorganism in its follow-up Storage.According to the experimental results of the second chapter, choose the blanchingtemperature90℃,the blanching time60s, pH5.5, and immerse in color-protectionsolution of350μg/mL Zn²⁺,400μg/mL citric acid, under50℃soak for30min.According to the results of the fourth chapter, choose processing pressure450MPa、processing time30min and temperature35℃.By change analysis of quality and microorganisms during storage, to conclude,the result of heat combined with ultra-high pressure treatment on walnut maleanthotaxy was obviously better than the other two treatments, this means dual effect ofheat combined with ultra-high pressure can kill most enzymes and microorganisms ofwalnut male anthotaxy, So that it could be kept a good sensory characteristics andquality during storage.