Composition analysis of volatile compounds in 114 germplasms of peaches evaluated by HS-SPME with GC-MS

Abstract Using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), we investigated the composition of volatile compounds in 114 peach germplasms across three harvest seasons (June, July, and August), three types (round peach, nectarine, and flat peach), two flesh colors (white and yellow), three levels of total soluble solids (TSS) content (high, medium, and low), and three categories of single fruit weight (SFW) (large, medium, and small). A total of 41 volatile compounds were identified in all 114 germplasms, including nine volatile categories: aldehydes (15), esters (5), lactones (8), alcohols (3), terpenols (4), ketones (2), phenols (1), alkanes (2), and ether (1). The average contents of the nine volatile types were aldehydes>esters>lactones>alcohols>terpenols>ketones>phenols>alkanes>ethers. Most of the 24 germplasms harvested in June could be clearly distinguished from the 30 germplasms harvested in August in the principal component analysis (PCA) plots (PC1, PC2, and PC3) of the three harvest seasons, which had much better discriminability than hierarchical clustering heatmap. In the PCA plots of the three TSS classifications, considerable separations occurred between 39 high TSS germplasms and 39 low TSS ones. In the PCA plots of classifications of the three SFW, three types, and two flesh colors, germplasms of different categories highly overlapped with each other. In the PCA (PC1 and PC2) loading plots, weights for distinguishing 114 germplasms of the five classifications were all in the order of trans-2-hexenyl acetate>benzaldehyde>methyl benzoate>2-hexenal>hexanal>linalool>hexyl acetate>2-ethylhexanol>γ-decalactone>the other 32 volatile components.