Abstract:To provide a theoretical basis for the flavor quality control of essential oils of citrus peels, the composition and content of volatile substances in essential oils of 4 varieties of citrus peels were analyzed and identified by headspace-solid phase microextraction-gas chromatography-mass spectrometry, and the relative odor activity values were used to analyze the key aroma components. The results showed that a total of 62 volatile components were identified in 4 varieties of citrus peel essential oils, including 13 monoterpene, 14 sesquiterpene, 5 alkanes, 12 alcohols, 8 esters, 4 aldehydes, 3 ketones, 2 ethers and 1 kinds of acids. The citrus peel essential oils of the 4 varieties all had the highest content of hydrocarbon compounds (89.00 %~95.00 %), and the content of D-limonene in all components was significantly higher than that of other compounds. According to the compound composition, the 4 varieties of citrus can be divided into two chemical types: limonene/γ-terpinene type and limonene//3-carene type. The key aroma components of 4 varieties of citrus peel essential oils were screened by ROAV value, and a total of 24 key aroma substances were screened. Among them, the substance that contributed the most to the flavor of Citrus meyerii Y. Tan. peel essential oil was perilla aldehyde, and there were 10 key aroma substances in total. Linalool is the substance that contributes the most to the flavor in the essential oils of fruit peel of Citrus unshiu Marc., Citrus aurantium L. and Citrus Wilsonii Tanaka , and the key aroma substances are 12, 20 and 20, respectively. These key aroma substances play an important role in the aroma quality of citrus peel essential oils. This study provides a theoretical reference for the quality evaluation of citrus peel essential oil and the development and application of citrus essential oil.