热烫方式对桃微观结构、酶促褐变及相关品质的影响

Effects of Blanching Methods on Microstructure,Enzymatic Browning and Related Quality of Peach

本实验采用热水与蒸汽两种热烫方式对桃进行预处理,研究其对微观结构、酶促褐变及相关品质的影响,确定桃脯前处理的最佳热烫条件。结果表明:随热烫时间(0~80 s)的增加,两种处理方式对桃品质的影响基本一致,表面微观结构塌陷、多酚氧化酶(PPO)和过氧化物酶(POD)钝化失活、质构下降、褐变度减弱、V_(C)含量降低、总酚含量及抗氧化能力上升。相关性分析和聚类分析结果表明:PPO、POD、硬度、褐变度、V_(C)间呈极显著相关(P<0.01);总酚、DPPH·清除能力、亚铁离子还原能力间呈极显著相关(P<0.01)。热水与蒸汽热烫前40 s内各理化品质变化接近,具有较高的相关性,而热水与蒸汽热烫60 s和80 s的品质变化相关程度较高。总之,相比于热水处理,蒸汽处理能较好地维持桃的品质。当蒸汽处理80 s时,在有效钝化PPO和POD的基础上,仍能维持相对饱满的组织结构和较好的色泽品质,且V_(C)含量也保持在较高水平,是适宜桃脯前处理的最佳热烫条件。

In this study,hot water and steam blanching were used to pretreat peach.The effects of two blanching treatments on microstructure,enzymatic browning and related qualities of peach were studied for determining the suitable blanching condition.The results showed that the effects of two treatments on peach were similar with the increase of blanching time(0~80 s)in general,the surface microstructure collapsed,PPO and POD inactivated,texture declined,the browning degree and V_(C) content decreased,total phenol content and antioxidant activity increased.Correlation and cluster analysis showed that PPO,POD,hardness,browning degree and V_(C) were extremely significant correlated.And the total phenol,DPPH•scavenging capacity and FRAP were extremely significantly correlated.The changes in physicochemical quality of hot water and steam blanching for 40 s were similar,and showed a high correlation.The quality changes of hot water and steam blanching for 60 s and 80 s were highly correlated.Overall,steam blanching maintained the better quality of peach compared with hot water treatment.When blanching for 80 s,steam blanching could effectively inactivate PPO and POD and maintain preferable tissue structure,and it showed better color quality and higher V_(C) content than those of hot water treatment.Hence,steam blanching for 80 s was the best blanching condition for preserved peach processing.