Abstract: Changes of free and glycosidically bound aroma compounds in ‘Ruiguang 1’ nectarines were investigated during postharvest storage at room temperature (20 ℃) or low temperature (1 ℃). Enzymatic hydrolysis was used to release the bound aroma compounds. Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used for qualitative and quantitative analysis of the free and bound aroma compounds in nectarines. The correlation between bound aroma compounds and soluble sugars was studied. Results showed that the compositions of free and bound aroma compounds were significantly different in nectarines stored at 20 ℃ and 1 ℃. In nectarines storage at 20 ℃, a total of 37 free aroma compounds and 30 bound ones were identified, of which, 8 compounds were detected in both free and bound forms. The free aromas decreased until day 4 and then increased until day 6 but decreased again on day 8. The bound aromas decreased to the minimum on day 6 then increased on day 8. In nectarines stored at 1 ℃, a total of 21 free aroma compounds and 32 bound ones were identified, of which, 7 compounds existed in both free and bound forms. The free aromas decreased with storage time, while the bound aromas increased at the beginning and then decreased. Correlation analysis showed a significant correlation between the bound aromas and the soluble sugars, especially sucrose, showing the highest correlation coefficient.

Key words: nectarine; free aroma compounds; bound aroma compounds; soluble sugar; gas chromatography-mass spectrometry