1-MCP结合自发气调包装对‘空心李’果实软化和细胞壁代谢的影响

探讨果实软化与细胞壁代谢之间的关系及1-甲基环丙烯(1-MCP)结合自发气调包装(MAP)对果实软化的调控机制,为生产中李果实软化问题提供理论依据和技术参考。笔者以贵州省特色果品‘空心李’为试材,通过测定果实的硬度、细胞壁代谢成分和细胞壁代谢酶活性的变化,研究1-MCP、MAP及两者结合(1-MCP+MAP)对(20±1)℃下果实软化的抑制效应。结果表明：（1）与对照（直接放于纸箱内）相比,1-MCP、MAP及1-MCP+MAP处理抑制了果实硬度下降,原果胶和纤维素降解,抑制了多聚半乳糖醛酸酶(PG)、果胶甲脂酶(PME)和纤维素酶(Cx)活性增加,抑制效果为1-MCP+MAP>1-MCP>MAP。（2）果实硬度的下降与原果胶和纤维素含量呈显著正相关,与可溶性果胶含量关系表现不一,1-MCP和1-MCP+MAP处理与可溶性果胶含量呈显著负相关,而对照和MAP处理与可溶性果胶含量没有表现出明显的相关性。1-MCP、MAP、1-MCP+MAP处理和对照果实硬度的下降与PG和PME活性存在显著负相关,对照和MAP处理的果实硬度与Cx活性表现显著负相关,1-MCP和1-MCP+MAP处理果实硬度与Cx活性没有表现相关性。1-MCP结合MAP对沿河‘空心李’果实硬度下降、细胞壁物质降解及其相关酶活性有显著抑制作用,能够抑制‘空心李’果实软化,延长保鲜时间,减少采后损失。

Effects of 1-MCP Combined with MAP on Softening and Cell Wall Metabolism of ‘Kongxin’ Plum

The objective is to explore the relationship between the fruit softening and cell wall metabolism and fruit softening regulatory mechanism of Prunus salicina ‘Kongxin’ by 1-methylcycropene (1-MCP), modified atmosphere packaging (MAP) and the combination of 1-MCP and MAP, and to provide technical references for solving the problem of plum fruit softening after harvesting. With P. salicina ‘Kongxin’ fruits as experimental materials, the changes of firmness, cell wall compositions, the metabolism-related enzyme activities under 1-MCP, MAP, and 1-MCP+MAP treatment during storage at (20±1)℃ for twelve days were investigated. The results were as follows: (1) compared with control (placed directly in carton), 1-MCP, MAP and 1-MCP+MAP delayed the decrease of fruit firmness and the degradation of protopectin and cellulose, and inhibited the enzyme activities of polygalacturonase (PG), pectin methylesterase (PME) and cellulase (Cx), the inhibitory effect of the treatment was 1-MCP+MAP>1-MCP>MAP; (2) the decrease of fruit firmness was obviously and positively correlated with the content of protopectin and cellulose, and was not consistent with the change of soluble pectin content; 1-MCP and 1-MCP+MAP treatment were negatively correlated with soluble pectin content, while the control and MAP treatment showed no significant correlation with soluble pectin content; there was a significantly negative correlation between the decrease of fruit firmness under 1-MCP, MAP, 1-MCP+MAP and control treatment with PG and PME activities, but there was a mixed relationship between the fruit firmness and Cx activity, including a significantly negative correlation in the control and MAP treatment, while no significant correlation in 1-MCP and 1-MCP+MAP treatment. The results indicated that 1-MCP combined with MAP treatment could significantly inhibit the firmness decline, the degradation of cell wall substances and the enzyme activities in the process of softening, to control the softening of P. salicina ‘Kongxin’ fruits, prolong the storage and reduce the loss after postharvest.