The Effect of Air-source Heat Pump Bulk Curing Barn on the Main Physiological Changes and Quality of Flue-cured Tobacco

In order to further explore the curing effect of air-source heat pump curing barn, the mature middle leaves of Zhongchuan 208 were used as experimental materials to study the main physiological changes of tobacco leaves during the curing process and quality of tobacco leaves cured in air-source heat pump and coal-fired bulk curing barn. The results showed that with the curing process, the chlorophyll, carotenoid, water and starch contents of tobacco leaves in different energy bulk curing barns gradually decreased, carotenoid/ chlorophyll ratio, total sugar and reducing sugar increased. Compared with the coal-fired bulk curing barn, the pigment content of tobacco leaves in the air-source heat pump bulk curing barn decreased faster. The water loss was faster. The carotenoid/ chlorophyll ratio was higher by 5-9 percentage points from the end of 38 ℃ to the end of 54 ℃. The carotenoid/ chlorophyll ratio was higher by 1.33 and 0.2 respectively at the end of 54 ℃ and 68 ℃. The starch content was lower, the reducing sugar was higher, and the starch content decreased by 47.25% and reducing sugar increased by 11.37% at the end of 68 ℃. The proportion of high-grade tobacco increased by 7.03 percentage points, and the average price of cured tobacco leaves increased by 1.37 yuan/kg. The total score of sensory quality increased by 2.5 points. To sum up, the air source heat pump bulk curing barn is beneficial to the yellowing and water loss coordination of tobacco leaves, reducing the starch content, improving the quality and benefit of tobacco leaves, which provide technical support for air-source heat pump clean energy to replace coal-fired bulk curing.