Changes Of Nutritional Components And Antioxidant Activity Of Pomegranate Juice During Process

Xinjiang is China’s earliest cultivation areas of pomegranate. Because of its good quality, bright color and high nutritional value, it is popular among Chinese. But various reasons, such as heating and oxidation etc. easily lead to pomegranate juice color change, nutritional components and antioxidant activity component loss in the production process. This paper takes Kashi sour pomegranate as experimental materials, the polyphenol, flavonoids, anthocyanins, Vc, browning index, DPPH, free radical scavenging rate, color were the experiment index to study the changes of functional factors.the anthocyanin and procyanidine in the pomegranate juice during the processing. The results are as follows:(1) Freeze concentration (FC), vacuum freeze concentration (VFC) and vacuum heat concentration (VTC) were used in this paper to study the effect on the active component and nutritional components in pomegranate juice with different processing ways. The experiment results showed that, with the increase of soluble solids, polyphenol content, flavonoids content, Vc content, DPPH radical scavenging ability, anthocyanin content were all increased in three concentrated samples, but VFC increase fastest. FC, VFC, VTC process polyphenol content by2.495mg/mL were increased to3.052,3.220,2.742mg/mL,0.753mg/mL respectively by flavonoids content was increased to0.976,0.996,0.895mg/mL,0.311mg/mL respectively, the anthocyanin content by up to0.356,0.409,0.343mg/mL,0.020mg/Vc content by were increased to0.056,0.063,0.041mg/mL, DPPH radical scavenging capacity from93.22%rise to94.49%,94.76%respectively,93.95%,browning index by1.595respectively increased to1.887,1.756,2.159.(2) The change mechanism of pomegranate anthocyanin and procyanidine in heating, microwave sterilization, ultraviolet irradiation and food additives during processing were studied in this paper. Temperature and oxidant had a great impact on pomegranate anthocyanins and procyanidine. The pomegranate anthocyanin and procyanidine content declined rapidly with the increase of heating temperature and oxidant amount. Microwave pasteurization had no obvious effect on the anthocyanin and procyanidine in pomegranate juice, ultraviolet radiation had no obvious effect on the anthocyanin but had a relatively greater effect on procyanidine. Among four kinds of common food additives (Citric acid, sodium benzoate, potassium sorbate, Vc),the (?)itric acid and Vc have no obvious effect on the anthocyanin and procyanidine, but dium benzoate and potassium sorbate have an obvious effect on the anthocyanin nd procyanidine. Different pH have an great impact on the pomegranate anthocyanin and procyanidine, the pomegranate juice showed red at pHl-3, light red at pH4, micro yellow at pH5-6, light yellow at pH7and yellow at pH8-10.(3) The change of nutritional components and antioxidant activity component in the concentrated pomegranate juice were studied under-4℃and25℃during storage process. The results show that, the storage temperature have an obvious effect on the anthocyanin and Vc, the anthocyanin and Vc decreased sharply with the temperature increases. The polyphenol and flavonoids content is relatively stable during storage.