Abstract: In this study, changes in the contents of methanol and ethanol during the fermentation of Jiaosu (fermented fruit juice) made from ‘Pingguoli’ pear fruit were monitored. Solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS), principal component analysis (PCA) and relative odor activity value (ROAV) were used to further analyze the dynamic changes in aroma components during fermentation. The results showed that the contents of methanol and ethanol initially increased to their maximum values of (0.152 ± 0.017) and (3.927 ± 0.025) g/L on the 20th and 50th day, and then declined to (0.026 ± 0.000) and (2.623 ± 0.071) g/L on the 80th day, respectively. A total of 40 aroma components, mainly including esters, alcohols, phenolic compounds, acids and aldehydes, were detected during fermentation. PCA indicated that alcohols, aldehydes and phthalic acid esters (PAEs) were the main aroma components that resulted in the flavor changes during the early stage of fermentation, while fatty acid ethyl esters (FAEEs) and phenolic compounds became the main aroma components which led to the flavor differences during the middle and late periods of fermentation. ROAV evaluation demonstrated that some of the key aroma components changed from decanal and 1-nonanal to eugenol during fermentation. This study provides basic data for the high-value utilization and deep processing of ‘Pinguoli’ pear Jiaosu.

Key words: ‘Pinguoli’ pear; Jiaosu; aroma components