Abstract:

This study aimed to clarify the effects of cold storage time on aroma components of grape during subsequent shelf
life at room temperature. Suffolk Red seedless grapes were detected for changes in volatile components during the shelf life
(on days 0, 3 and 6) after cold storage for 15 and 45 days by head space solid-phase microextraction (HS-SPME) combined
with gas chromatography-mass spectrometry (GC-MS) and for changes in aroma components during the shelf life after
cold storage for 15, 30, 45 and 60 days using electronic nose (e-nose). The results showed that volatile components of grape
were mainly composed of esters, aldehydes and alcohol, with ethyl acetate, aoba aldehyde, n-hexyl alcohol, leaf, citronellol
being the major volatile components. After cold storage for 45 days, the relative contents of esters and alcohols were lower
than those of the grapes stored for 15 days whereas the content of aldehydes was higher in the grapes cold-stored for 45
days during the shelf life. E-nose combined with linear discriminant analysis (LDA) could effectively distinguish the grapes
cold-stored for different times. Volatile aroma components of grapes were not overlapped during the shelf life after all cold
storage periods except on days 0 and 3 of the shelf life after 15-day cold storage, that was, volatile components of grapes
varied widely with prolonged storage time at room temperature after cold storage, which could be distinguished effectively
by e-nose. Loading analysis (LA) showed that hydrogen sulfide and terpenes (W1W), aroma components (W1S), and ethanol
(W2S) sensors were the major contributors to volatile odors, which was consistent with the results of HS-SPME-GC-MS
analysis. Therefore, it is feasible to use HS-SPME-GC-MS combined with electronic nose to distinguish grapes during the
shelf life at room temperature after cold storage for different times based on their aroma components.

Key words: grape, volatile components, cold storage time, shelf life, head space solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS), electronic nose