1-甲基环丙烯对李果实采后衰老期间非挥发性风味物质影响的多变量分析

采用多变量分析的方法研究1-甲基环丙烯(1-MCP)对‘黑琥珀’李果实20℃贮藏期间非挥发性风味物质形成的影响。结果表明：李果实中主要的糖酸组分是D-果糖、D-葡萄糖、蔗糖、山梨糖醇和苹果酸，D-果糖在采收时与贮藏前期释放较多，蔗糖在贮藏后期时含量较高；1-MCP处理抑制了蔗糖向D-果糖和D-葡萄糖的转化，延缓了可溶性固形物含量的下降，在贮藏后期，1-MCP处理诱导苹果酸、柠檬酸和L-天冬氨酸含量的降低，而增加了果实的pH值。偏最小二乘回归与通径分析结果表明，感官甜酸比与山梨糖醇、蔗糖呈高度正相关，酸度与苹果酸呈高度正相关，且蔗糖是甜酸比的主效因子，对甜酸比的影响主要是通过对山梨糖醇、D-果糖和苹果酸的间接效应实现的。

Multivariate Analysis of the Effect of 1-Methylcyclopropene (1-MCP) on Non-Volatile Flavor Compounds in Plum Fruits during Postharvest Ripening

In the present study, the effect of 1-methylcyclopropene (1-MCP) on non-volatile flavor compounds in post-harvest
Blackamber, plum during storage at 20 ℃ was explored by using principal component analysis (PCA), correlation analysis, partial least squares regression (PLSR) and path coefficient analysis. The results showed that the major non-volatile compounds inBlackamber, plum fruits were D-fructose, D-glucose, sucrose, sorbitol and malic acid. The level of D-fructose was higher at harvest period and the early stage of storage, and the release of sucrose was higher at the later stage of storage. 1-MCP treatment inhibited the transformation of sucrose to D-fructose and D-glucose, and delayed the decrease of SSC. At the same time, 1-MCP treatment induced the decrease of malic acid, citric acid and L-aspartic acid and the consequent increase of pH in plum fruits. PLSR and path analysis showed that sensory sweetness/sourness ratio was correlated strongly in a positive manner with sucrose or sorbitol and was affected mainly by sucrose as a result of its indirect effect on sorbitol, D-fructose and malic acid. Moreover, a high positive correlation between acidity and sensory sourness was observed.