板栗的酶促褐变特性及灭酶预处理研究

Study on enzymatic browning and blanching methods of chestnut

对冻藏板栗中多酚氧化酶(PPO)的活力及热稳定性进行了比较,研究低糖板栗果脯灭酶预处理及其对后续渗糖过程的影响。结果表明:板栗中影响褐变的酶主要有PPO和POD,其中PPO较POD热稳定性略高。冻藏后的板栗中PPO最适温度及pH分别为20℃和6.5。板栗加工中应以板栗PPO活力降至8%以下作为是否灭酶充分的标准。通过与热水烫漂灭酶、蒸汽灭酶比较发现,微波热烫处理可抑制低糖板栗果脯加工过程中的褐变,并有助于提高渗糖效率。微波灭酶的最佳条件是:功率密度4W/g,处理6min。

The activity and thermal stability of polyphenol oxidase （PPO） in frozed chestnut were studied. The blanching methods and their effects on candying processing of chestnut were also investigated. Results showed that the thermal stability of PPO was higher than POD,the optimum temperature and pH of PPQ were 20℃,6.5 respectively, When the relative activity of PPO was decreased to less than 8%,the enzymes causing browning in chestnut were estimated to be inactivated enough, Compared with the way of hot water and steam blanching, enzymatic browning in chestnut was inhibited efficiently by microwave blanching ,and the sugar impregnation into chestnut was enhanced too in the processing of low-sugar candied chestnut, The optimal treatment of microwave blanching was that chestnut was heated at 4W/g power indensity for 6min.