Analysis of aroma quality and mining of synthetic genes for characteristic aroma volatile compounds of “Chachiensis”

Aroma is an important indicator to evaluate the quality of Citrus reticulata “Chachiensis” and its processed product Guangchenpi (GCP). In this study, gas chromatography/olfactometry-mass spectrometry (GC/O-MS) combined with aroma extract dilution analysis (AEDA) was used to identify the key aroma-active compounds of “Chachiensis” peels. Then the aroma wheel of “Chachiensis” peels integrated with “GCP” was constructed. Finally, the genes involved in the biosynthesis of key aroma-active compounds in “Chachiensis” were mined and characterized. The results showed that 32 aroma-active compounds were identified in “Chachiensis” peels, while 11 of them were identified as key aroma-active compounds including α-farnesene. The aroma wheel of “Chachiensis” peels integrated with “GCP” was constructed, which was composed of eight aroma types such as “fruity” and 19 aroma descriptors. A total of 11 terpene synthase (TPS) genes involved in the synthesis of key aroma-active compounds in “Chachiensis” peels were mined, among which CTPS37 was found to synthesize α-farnesene and trans-β-farnesene in E. coli. This study provides a theoretical basis for the analysis of the formation mechanism of “Chachiensis” peel flavor and the healthy development of the GCP industry.