Storage stability of aroma volatiles in ultra-high pressure and thermally treated Thai green-chili pastes (Nam Prig Nhum)

Pressurized, pasteurized and untreated Thai green-chili pastes (Nam Prig Nhum) were kept at 4 °C, while sterilized samples kept at 30 °C for 8 weeks. Their volatile components were subsequently extracted at every-two-week interval using solid phase microextraction and identified by gas chromatography–mass spectrometry. The chromatograms showed that predominant volatiles present in untreated Nam Prig Nhum were sulfide, hydrocarbon and ester classes, other volatile classes such as aldehydes, ketones, furans, pyrazines, alcohols and acids existed to the lesser extent. Among these volatiles, some sulfides, hydrocarbons, furans and pyrazines were the thermally developed compounds, particularly diallyl sulfide, allyl methyl disulfide and allyl methyl trisulfide. Desired volatiles including ester, aldehyde and alcohol classes in pressurized samples showed higher retention than those thermally treated Nam Prig Nhum. However, most volatiles reduced or lost upon storage.