The phenotypic characteristics (including single fruit mass, longitudinal diameter, transverse diameter, and fruit shape index) of 59 varieties of Chinese olive fruit were assessed and categorized based on probability. 15 Chinese olive varieties with varying fruit shape indexes and genetic backgrounds were selected for analysis of volatile compounds using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The results indicated a wide range of variation in four phenotypic traits, with coefficients of variation (CV) between 10.70% and 26.67%. The Kolmogorov-Smirnov (K-S) test showed that the data of fruit shape index, longitudinal diameter, and transverse diameter followed a normal distribution, allowing for their categorization based on probability. A total of 886 volatile compounds were identified including 186 terpenoids, 157 heterocyclic compounds, 146 esters, 73 ketones, 64 hydrocarbons, 64 alcohols, 53 aldehydes, 51 aromatic hydrocarbons, 21 acids, 21 amines, 20 phenols, and 30 other compounds at concentration levels ranging from 1881.70 to 6727.40 μg/g of fresh mass. Terpenes were the dominant volatile compounds in Chinese olive fruit, accounting on average for 52.49% of the total volatile compounds. The most abundant terpene was α-pinene, with a relative content of 7.13% (309.66 μg/g of fresh mass). A total of 181 characteristic aroma components were identified using odor activity value (OAV) analysis, contributing to the overall aroma profile of Chinese olive fruit. Among these components, the heterocyclic compound 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone was the biggest contributor with the highest OAV of 2468148.28, being responsible for sweet aroma. Utilizing principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) analysis, 6 differential characteristic aroma components were identified among different varieties of Chinese olive fruit. Notably, α-farnesene had the highest variable importance in the projection (VIP) value with an OAV of 19.71, being responsible for floral and fruity aromas. These findings serve as a valuable reference for the quality grading of Chinese olive fruit, as well as for future investigations into its aroma formation mechanism and quality improvement.
XI W P, ZHANG B, LIANG L, et al. Postharvest temperature influences volatile lactone production via regulation of acyl-CoA oxidases in peach fruit[J]. Plant Cell and Environment, 2014, 37(7): 1722. DOI:10.1111/pce.12356.
SIEGMUND B. Biogenesis of aroma compounds: flavour formation in fruits and vegetables[M]. Cambridge: Woodhead Publishing, 2015: 127-149.
LI L, MA X W, ZHAN R L, et al. Profiling of volatile fragrant components in a mini-core collection of mango germplasms from seven countries[J]. PLoS ONE, 2017, 12(12): e0187487. DOI:10.1371/journal.pone.0187487.
VAN GEMERT L J. Complilations of odour threshold values in air, water and other media (Part Ⅱ)[M]. Utrecht: Oliemans Punter & Partners BV, 2011: 207-359.
YUE C, CAO H L, ZHANG S R, et al. Aroma characteristics of Wuyi rock tea prepared from 16 different tea plant varieties[J]. Food Chemistry: X, 2023, 17: 100586. DOI:10.1016/j.fochx.2023.100586.
GUO X Y, HO C T, WAN X C, et al. Changes of volatile compounds and odor profiles in Wuyi rock tea during processing[J]. Food Chemistry, 2021, 341: 128230. DOI:10.1016/j.foodchem.2020.128230.
XUE J J, LIU P P, YIN J F, et al. Dynamic changes in volatile compounds of shaken black tea during its manufacture by GC × GC-TOFMS and multivariate data analysis[J]. Foods, 2022, 11(9): 1228. DOI:10.3390/foods11091228.
SUN P, XU B, WANG Y, et al. Characterization of volatile constituents and odorous compounds in peach (Prunus persica L) fruits of different varieties by gas chromatography-ion mobility spectrometry, gas chromatography-mass spectrometry, and relative odor activity value[J]. Frontiers in Nutrition, 2022, 9: 965796. DOI:10.3389/fnut.2022.965796.
SHENG X F, HUANG M Z, LI T T, et al. Characterization of aroma compounds in Rosa roxburghii Tratt using solvent-assisted flavor evaporation headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry and gas chromatography-olfactometry[J]. Food Chemistry: X, 2023, 18: 100632. DOI:10.1016/j.fochx.2023.100632.
ANDRES B P, LINA M L G, GONZALO T O. Volatilome study of the feijoa fruit Acca sellowiana (O. Berg) Burret. with headspace solid phase microextraction and gas chromatography coupled with mass spectrometry[J]. Food Chemistry, 2020, 328: 127109. DOI:10.1016/j.foodchem.2020.127109.
GUADAGNI D G, BUTTERY R G, HARRIS J. Odour intensities of hop oil components[J]. Journal of the Science of Food and Agriculture, 1966, 17(3): 142-144. DOI:10.1002/jsfa.2740170311.
BUTTERY R G, LING L C, LIGHT D M. Tomato leaf volatile aroma components[J]. Journal of Agricultural and Food Chemistry, 1987, 35(6): 1039-1042. DOI:10.1021/jf00078a043.
YAN J W, BAN Z J, LU H Y, et al. The aroma volatile repertoire in strawberry fruit: a review[J]. Journal of the Science of Food and Agriculture, 2018, 98(12): 4395-4402. DOI:10.1002/jsfa.9039.