Studies On The Physical And Chemical Quality And Antioxidative Property Of Different Persimmon Juice Varieties

Persimmon was originated in China, with possess abundant nutritive value and nique health care value, and it was a kind of ecological fruit trees with hign edible values and evelopment potential. At the present time, the kind of persimmon product was single, and the resource utilization efficiency of persimmon was low, and its characteristic was juicy, high sugar content.and advantageous to the storage. If on the basis of persimmon juice, we can develop other new products, so can consume raw materials massively for a short time.during the harvest of persimmon.This paper studied the effect of variety and enzyme treatment on juice yield and quality of persimmon juice, and the effect of machining operations and storage on quality and antioxidative propertie, so determine the variety and condition that was fit to machining. Evidently, the result was acceptable.1. The effect of variety and enzyme treatment on juice yield and quality of persimmon juice: This paper studied the effect of persimmon variety, pectin content, cellulose content, the type of enzyme and enzymatic hydrolysis conditions on juice yield and quality of persimmon juice. The resuits indicated that juice yield of Jingmian persimmon was the most maximum, and the juice yield had a remarkable correlating with the content of pectin, but the relation was unapparent between juice yield and the content of fiber. It was the temperature that mpairs the juice yield of Jingmian persimmon. The optimum conditions of pectinase hydrolysis were determined as follows: 2.5ml/kg pectinase and pH 4.5, hydrolyzing for 2h at 55℃. The results of persimmon juice quality and monose composition showed that Jingmian ang Niuxin persimmon were rich in sugar and good in colour and quality.The main sugars such as glucose, fructose and Cane sugar are included in the three persimmon juice, and the content of glucose was highest. The content of monose in Jingmian and Niuxin persimmon was higher in the three varieties of persimmon. So the first selection of persimmon juice processing was Niuxin persimmon.2. The changes of quality of persimmon juice and antioxidantproperties in machining process.: the content of total sugar, polyphenol and total flavonoid was high in the three persimmon juice, and the three persimmon juice all had the scavenging effects of hydroxyl radicals, super oxide anion radical and DPPH radicals, and the scavenging was high. Thereinto, the content of total sugar, polyphenol, total flavonoid and antioxidiative effects in Niuxin persimmon juice were highest. The effect of clarifies, the sterilization process on the content of the main oxidation resistance material and antioxidant properties was more remarkable.But the oxidation resistance material and antioxidant properties of Niuxin persimmon juice were relatively more steady, and it had an advantage over Jingmian persimmon juice and Mopan persimmon juice.3. The changes of quality and antioxidant properties of persimmon juice during storage:The content of polyphenols, total flavonoids, vitamin C, carotenoids in three varieties of persimmon juice were decreased during storage, Thereinto, the content of Mopan persimmon juice declined most markedly;.The scavenging effects of hydroxyl radical scavenging, superoxide anion and DPPH? radical were showed a decreasing trend, which was consistent with the developing trend of main antioxidants.Under different storage temperatures, the change trend of antioxidants and antioxidant capacity in persimmon juice was also different, and low temperature storage was in favor of the preservation of antioxidants and antioxidant properties. But under the same conditions, the quality and antioxidant capacity of Niuxin persimmon juice was relatively stable, better than Jingmian persimmon juice and Mopan persimmon juice.