Effects of fan speed on starch and pigment degradation of tobacco leaves at yellowing stage during bulk curing.

In order to explore the effects of different fan speeds at the yellowing stage during bulk curing,the changes in the starch and pigment degradation of tobacco leaves were analyzed.The results showed that: from the beginning of curing to the end of 38 ℃ constant temperature,when fan speed was 1440 r/min,starch content in tobacco leaf was 15.21%,the rate of starch degradation was faster,and the content of reducing sugar was relatively high,being 9.84%.In the treatment of fan speed 960 r/min,after the end of constant temperature of 42 ℃,the rate of starch degradation was significantly faster than that in the treatment of 1440 r/min.The reducing sugar contents of tobacco leaves based on fan speed 960 r/min was the highest,which was 25.34% and had significant difference compared with the content based on fan speed 720 r/min and 1440 r/min.Chlorophyll a and Chlorophyll b contents of tobacco leaves based on fan speed 960 r/min at yellowing stage of bulk curing were significantly lower than the content based on fan speed 720 r/min and 1440 r/min,with 6.17 μg/g and 3.27 μg/g respectively,and carotenoid content was 138.83 μg/g,which was significantly lower than that based on fan speed 1440 r/min.