关键词: 添加剂, 刺梨果汁, 单宁, 品质稳定性

Abstract: This study was performed to investigate the effect of different additives such as chitosan, carboxymethyl chitosan, polyethylene pyrrole (PVPP) and gelatin on the contents of tannins, VC and flavonoids and SOD activity in Rosa roxburghii Tratt. (Cili pear) juice. Besides, the effect on the thermal stability of VC and flavonoids and SOD activity in the juice was also examined. The results indicated that chitosan had an excellent tannin removal effect with a removal rate of 66.40% when added to Cili pear juice at a concentration of 0.4 g/100mL. At the same concentration, carboxymethyl chitosan addition resulted in a removal rate of 52.40%. The tannin removal rates resulting from 0.5 g/100mL PVPP addition and 0.8 g/100mL gelatin addition were 61.30% and 54.40%, respectively. Moreover, chitosan improved the retention rates of VC and flavonoids, which were 96.86% and 97.55%, respectively at the concentration of 0.7 g/100mL, but had no significant effect on SOD activity (P ＞ 0.05). When each additive was added at the optimized concentrations individually, heating at 45 ℃ for 6 h resulted in an increase in the retention rates of VC and flavonoids and SOD activity than at the same temperature for 50 h and at 100 ℃ for 30 min. Further, carboxymethyl chitosan showed a better retention of VC in Cili pear juice after heating at 45 ℃ for 6 h than other three additives, reaching 72.88% (P ＜ 0.05). The retention rates of flavonoids and SOD activity of chitosan treatment group were 96.44% and 78.26% (P＜ 0.05), respectively, and of SOD activity of carboxymethyl chitosan treatment group 78.95% (P＜ 0.05).

Key words: additives, Rosa roxburghii Tratt. (Cili pear) juice, tannin, quality stability