Research On The Changes Of Aroma Compounds In Green Tea During Storage

This study using the method of HS-SPME-GC-MS to extract and analyze the aroma compounds in green tea treated by different temperatures and moistures, and then analyzed the raltionship between these factors and aroma compounds. This study not only improved the research of this area but also provide guidances for expert-oriented enterprises.The results showed that the aroma compounds in green tea stored in environmental embrittlement changed slowly. We hadn't found any stale odor compounds in them, but we found that after storing tea samples produced some small molecular aldehydes like melon aldehyde, clclocitral, butanal and so on.Long-term or shorten-term treatments can both affect the compositon of tea aroma compounds. The green tea had made heavy changes by certain treatments, tea samples made a kind of moisture and heat process like fermentation in black tea and pile-permentation in pu-er tea. At last, alcohols and alkenes compounds that had faint scent or flowery odour decreased, but alkanes and furan compounds increased.Long-term temperature and moisture treatments affected odor-compounds in tea largely, the content of alcohol-compounds decreased while the content of alkane-compounds increased after treating. During the processing, the content of alcohols reduced first then increased, the content declined to the lowest, which accounted for only 5～10% of the total extracted aroma compounds, after treating 60 days, the content increased to 10～25%. But the change of content of alkanes was opposite, the content increased first then descended appreciably. After treating 60 days, the content of alkanes increased to 40～50% of the total extract aroma compounds. The higher the temperature, the faster varies of the odor compounds. The content of alkanes in tea samples treated by 55℃and different moisture only need 15 days can reach the level of room-controlled group, saving 45 days. Compared with tea samples stroed in environmental embrittlement, the tea samples shorten-hetated by 40℃,50℃and 60℃had great changes. Stored in room conditions by 60 days, the content of alcohols decreased to the 34% of total extracted aroma compounds, but the tea samples treated by 40℃for 6 hours only need 30 days, and other treatments just need 10 days. Stored in room conditions by 60 days, the content of alkanes increased to the 12% of total extracted aroma compounds, but all treatments only need 30 days can reach the same level, saving 30 days.Higher temperature treatments can create furan, naphthalene easily, and these compounds had caramel sweet and smoke odor. The higher temperature the earlier these chemical meterials produced. We had detected these compounds in tea samples treated by 55℃for 15 days,45 days earlier than 40℃treatments.Therefore, shorten-term temperature and moisture treatments affected the composition of tea aroma compounds largely. These shorten-term treatments can speed up the change of tea quality, superadded they can save store time, so they can save the costs. At the same time, these treatments can finished in one day, meaned a reality application for factory production.