Effect Of High Pressure Processing On Quality Of Chinese Bayberry Juice

With the increase of consumer demand to food quality, it is necessary to develop novel processing methods which use minimal heat and additives, and result in fresh like products of superior nutritional quality. High pressure processing (HPP) is an alternative processing technology to inactivate microorganisms with high retention of color, flavor and nutrients of fruit and vegetables due to its limited effect on the covalent bonds of low molecular-mass compounds.The objectives of this study were (1) to evaluate the effect of HPP on microorganism inacitivation,(2) to analyze the properties (pH, soluble solid content, color, anthocyanin and ascorbic acid) of pressure treated bayberry juice during storage, compared with untreated samples and heat treated samples (3) to investigate the volatile components of Chinese bayberry after HPP. The results show that:(1) HPP could effectively destruct the microorganism in Chinese bayberry juice and inhibit the growth of microorganism in the following storage period. After500MPa,5min HPP treatment, Chinese bayberry can meet the fruit and vegetable juice beverage hygiene standards, and in4℃and25℃storage period the microorganism number gradually reduced with time. After50℃,5min heat treatment, the microorgamism number conforms to the standards, but it recovered in the storage period rapidly.(2) Compared with untreated sample, HPP had no significant influence on pH, soluble solids content of Chinese bayberry juice.(3) HPP treated juice had less reddish color compared with fresh juice.(4) The retention ratios of anthocyanin and ascorbic acid content after pressure treatment were more than98%and96%, respectively. Both anthocyanin and ascorbic acid content of pressure treated juice were more stable during storage as compared with those of the untreated juice. The degradation of anthocyanin and ascorbic acid of samples during storage could be described using first order kinetics.(5) It was observed that there was a significant (p<0.01) correlation between anthocyanin and ascorbic acid content for all tested samples of Chinese bayberry juice.(6) According to the retention of anthocyanin and ascorbic acid content after HPP treatment, and the degradation rate in storage period,500MPa and10min were selected as the optimal pressure and holding time of HPP treatment.(7) The aroma components in Chinese bayberry juice after HPP and heat treatment were evaluated by combing SPME and GC-MS method. The top three of relative quatitive componets were1-Hexanol,3-Hexen-l-ol,(Z)-, and Caryophyllene. After HPP, the relative contents of three main components were improved compared with untreated sample. Though the aroma of fruit juice does not necessarily depend on the quantitative concentration of any volatile compound. The results of this research could be used for future sensory evaluation, and provide theoretical basis for practical application.