基于主成分分析和聚类分析麝香草酚微胶囊/魔芋葡甘露聚糖/低酰基结冷胶可食性复合涂膜对蓝莓品质的综合评价

Comprehensive evaluation of edible composite coatings with thymol microcapsule/konjac glucomannan/low-acyl gellan gum on blueberry quality based on principal component analysis and cluster analysis

该研究旨在建立综合评价麝香草酚微胶囊/魔芋葡甘露聚糖/低酰基结冷胶(thymol microcapsule/konjac glucomannan/low-acyl gellan gum,TKL)可食性复合涂膜对蓝莓保鲜效果的方法。以晚熟蓝莓品种‘巴尔德温’为试材,从感官、生理生化、营养成分、色泽和质构等角度,采用主成分分析(principal component analysis,PCA)、聚类分析、相关性分析等综合评价TKL采前喷涂对蓝莓贮藏品质的影响。结果表明,TKL涂膜处理减缓了蓝莓贮藏过程中感官、果形指数、总酸、硬度、L^(*)、b^(*)、H^(*)和弹性的下降;抑制了失重率、腐烂率、丙二醛、a^(*)、C^(*)值的增加;维持较高的可溶性固形物、总酚、总黄酮、花青素含量、咀嚼性和回复性,从而减缓了蓝莓品质的劣变。PCA分析得到2个主成分,累计方差贡献率为86.90%。PCA得分与感官评价拟合呈极显著正相关(P<0.01)。聚类分析显示,TKL涂膜处理21~56 d的蓝莓品质与对照组7~35 d聚类同一类。TKL涂膜将贮藏期从42 d延长到63 d。PCA与聚类分析结合,可更准确地评价TKL涂膜对蓝莓采后综合质量的影响,为TKL涂膜在采后果实的保鲜应用提供理论依据。

The study aimed to establish a comprehensive method to evaluate the effects of thymol microcapsules/konjac glucomannan/low acyl gellan gum(TKL)edible composite coating on postharvest quality of blueberry.The late-ripening variety Baldwin was used as the test material.Based on the sensory,physiological and biochemical,nutrient,color,and texture perspectives,representative indicators were selected to comprehensively evaluate the effect of TKL preharvest spraying on blueberry quality using principal component analysis(PCA),cluster analysis,and correlation analysis.Results showed that the TKL coating treatment slowed down the decrease in sensory,fruit shape index,titratable acid,hardness,L^(*),b^(*),H^(*),and springing during storage of blueberry,reduced the increases in weight loss ratio,decay rate,malondialdehyde,and C^(*),and increased the contents of soluble solid,chewiness,resilience,total phenols,total flavonoids,and anthocyanidin.The TKL coating effectively slowed down the deterioration of blueberry quality.PCA analysis obtained 2 principal components with a cumulative variance contribution of 86.90%.The fitting of PCA scores with sensory values was an extremely significant positive correlation(P<0.01).Cluster analysis indicated that the blueberry quality of TKL coating treatment at 21-56 days was in the same category as the control at 7-35 days.Correlation showed that PCA scores were extremely significant and positively correlated with sensory evaluation(P<0.01).Cluster analysis showed that the quality of blueberry by TKL coating at 21-56 days was the same as that of the CK group at 7-35 days.The TKL coating treatment extended the storage period of Baldwin blueberry from 42 days to 63 days.The combination of PCA and cluster analysis could more scientifically,systematically,and accurately evaluate the effect of TKL coating on the postharvest preservation of blueberries,providing a theoretical basis for the application of TKL coating on postharvest fruit preservation.