Abstract:

The physicochemical qualities of sweet peppers with different packaging treatments during shelf-life at normal
temperature after storage at 10 ℃ for 15 days were comparatively evaluated in term of weight loss, vitamin C content and
sugar/acid ratio. Besides, the volatile components were also analyzed using head space solid-phase microextraction and gas
chromatography mass spectrometry (HS-SPME-GC-MS) and electronic nose technology. The aim of these experiments was
to investigate the effects of different packaging materials (no packaging, microporous bag, and 20 μm thick polyethylene
(PE) bag) on the volatile components and physicochemical qualities of sweet peppers during post-cold storage shelf-life. The
results showed that electronic nose could distinguish the whole volatile components of sweet peppers contained in different
packaging bags during different shelf-life periods after storage，which were mainly esters and alcohols. The contents of
volatile esters of sweet peppers decreased during shelf-life while alcohols increased. The relative contents of esters in the
control, microporous bag, and PE bag groups decreased by 47.33%, 23.43% and 51.39%,whereas alcohols increased by
68.73%, 56.80% and 72.96%, respectively. These results showed that microporous bags most significantly retarded the
decrease of esters and the increase of alcohols and effectively improved the aroma components of sweet pepper during shelflife
after storage, having better preservation effect than the control and PE group. The microporous bag treatment had the
highest levels of vitamin C and sugar/acid ratio. No significant difference in weight loss rate was seen between the
microporous bag and PE bag groups (P > 0.05), but both were significantly lower than the control group (P < 0.05).
Overall, microporous bags could most effectively preserve the physicochemical qualities of sweet peppers during shelflife
after storage.

Key words: sweet peppers, electronic nose, gas chromatography mass spectrometry (GC-MS), packaging, volatile components