Abstract:

In order to clarify the effect of curing barn types and moisture removal methods on the curing quality of tobacco leaves，the effects of the internal dehumidification heat pump bulk curing barn （closed-cycle curing barn）on the contents（mass fraction）of main chemical components，organic acids and neutral aroma components of flue-cured tobacco leaves were studied by half-leaf method，with the conventional moisture exhaust heat pump bulk curing barn （open-cycle curing barn） as control. The results showed that compared with the open-cycle curing barn，the total sugar content of flue-cured tobacco leaves in the closed-cycle curing barn was significantly（p<0.05）increased by 1.66 percentage points，the reducing sugar content was significantly increased by 2.30 percentage points，the ratio of reducing sugar to total sugar was significantly increased by 8.2%，the ratio of reducing sugar to total alkaloids was significantly increased by 8.7%，the starch content was decreased by 3.05 percentage points， the content of citric acid was decreased by 25.3%，the content of 2，4-heptadienoic acid was increased by 25.7%，and the content of γ-pentanoic acid was increased by 15.6%. The variable importance in projection （VIP） values showed that there were significant differences in the contents of 14 neutral aroma components in the flue-cured tobacco leaves of the closed-cycle curing barn compared with the open-cycle curing barn. The total sugar，reducing sugar，2，4-heptadienoic acid and γ-pentanoic acid content，ratio of reducing sugar to total sugar and the ratio of reducing sugar to total alkaloids of flue-cured tobacco leaves were significantly increased by using the closed-cycle curing barn，and the content of some neutral aroma components was significantly increased.

Key words: flue-cured tobacco, half-leaf method, closed-cycle curing barn, main chemical component, organic acid, neutral aroma component