Seasonal changes of volatile compounds and odor evaluation of Zanthoxylum bungeanum ‘Hanyuan’ fruit during the development

Knowing the content, compound, and key odor of volatile oil in the fruit of prickly ash during the development is important for improving product quality and determining a suitable harvesting period. Samples of Zanthoxylum bungeanum 'Hanyuan' fruit were collected at 31-115 day after flowering (AF) used for volatile oil extraction by the steam distillation method, and the volatile compounds were determined by gas chromatography-mass spectrometry (GC-MS), and the cluster and principal component analysis (PCA) were used for odor evaluation. The volatile oil content increased gradually with the fruit development, ranging from 0.4% to 8.5%, and no significant (P > 0.05) difference was observed between 100 d AF and 115 d AF. A total of 65 compounds were detected in volatile oils at the different stages; these compounds mainly included hydrocarbons, alcohols, esters, ethers, aldehydes, and ketones, which accounted for 96.36%-99.52% of the volatile oils. The main volatile compounds were alkenes, alcohols, and esters according to the number and relative content of the compounds in volatile oils. A total of 25 common compounds were detected in volatile oils at the different stages, which accounted for 93.99%-98.36% of the volatile oils, and (+)-limonene, linalool, myrcene, linalyl acetate, and 1,8-cineole had higher relative content than other compounds. The main compounds of volatile oils at the different stages were similar, but the relative content varied greatly. The relative content of (+)-limonene was observed to be the highest at all stages, myrcene and linalyl acetate showed an increasing trend, and linalool showed a decreasing trend with fruit development. The key odor compounds of Zanthoxylum bungeanum 'Hanyuan' fruit at the different stages were varied. Linalool, (+)-limonene, myrcene, 1,8-cineole, (+)-delta-cadinene, β-ocimene, (E)-β-ocimene, and geranyl acetate were key flavor compounds during the entire fruit period of Zanthoxylum bungeanum 'Hanyuan'. The comprehensive score of odor evaluation at the different stages ranked as 115 d AF > 100 d AF > 86 d AF > 74 d AF > 39 d AF > 64 d AF > 47 d AF > 56 d AF > 31 d AF. The optimal harvest period for Zanthoxylum bungeanum 'Hanyuan' fruit for obtaining a higher content of volatile oil and a comprehensive score of odor evaluation was 100-115 d AF.