油桃采后衰老与病害发生中挥发性物质变化的主成分分析

Changes of Volatile Substances in Nectarine during Postharvest Senescence and Diseases by Principle Component Analysis

采用固相微萃取与气相色谱-质谱联用技术,对油桃果实采后衰老与褐腐病害发生中近表皮和近果核的挥发性物质进行测定;用主成分分析(PCA)法研究不同样品挥发物谱的差异并对香气品质进行综合评价。结果表明,共检测到油桃果实挥发性物质14种,主要为C6化合物、酯类和内酯类物质。贮藏期间油桃果实挥发性物质逐渐由近果核处转向近表皮,褐腐病害发生后加速了这种转变。PCA结果表明,5-羟基-2,4-癸二烯酸-γ-内酯、γ-癸内酯、δ-辛内酯和乙醇可作为区分油桃果实贮藏4d时衰老与病害发生的标志性挥发物;C6醛类、乙醇和乙酸乙酯则可作为区分油桃果实贮藏0、2d与贮藏4、6d时的标志性挥发物。病害组贮藏2d后近表皮处香气品质最佳,贮藏4d后病害组香气品质远低于衰老组。

Volatile substances near the epidermis and stone of nectarine during postharvest senescence and brown rot were determinated using SPME-GC/MS,and principal components analysis（PCA） was applied to these complex GC/MS data of volatile compounds to facilitate differentiation and access aroma quality. The results showed that a total 14 compounds were identified. C6 compounds,esters and lactones were the major constituents. During storage,volatile compounds near the epidermis gradually turned to near the stone,and brown rot stimulated this trend. Results of PCA showed that 5-Hydroxy-2,4-decadienoicacid γ-lactone,γ-Decalactone,δ-Octalactone and ethanol could distinguish nectarine fruits during postharvest senescence from brown rot;while C6 aldehydes,ethanol and ethyl acetate could distinguish the samples of the early period（0 and 2 days） and late period of storage（4 and 6 days） . Aroma quality was best after 2 days,especially near the epidermis of brown rot fruits. Aroma quality of brown rot fruits was worse than senescence after 4 days.