Effects Of Loading Density Of Bulk Curing Barn On Physiology Characteristics Of Flue-cured Tobacco During The Process Of Flue-curing And The Quality Of Cured Leaves

This paper studied the effects of loading density on the change of physiology of flue-cured tobacco during the process of flue-curing and the quality of cured leaves with four levels of loading density treatments and two conditions of temperature and humidity of yellowing. The results showed that:1 .During the process of flue-curing,the water content decreased slowly at former stage , and increased fast in middle period, then decreased slowly again at later stage .The rate of losing water decreased with the loading density increasing.Under the same loading density ,the stage of quick losing water of 38℃ of yellowing was later than that of 42℃ of yellowing,while that stage under 80-85% comparative humidity of yellowing was faster than that under 90-95%.2.Under the same curing condition, the degree of lipid peroxidation was the lowest and the activity of peroxidase was the highest by treatment 55-56kg/m~3 in four treatments of loading density. Under the same loading density and the different controlling of yellowing temperature,the content of MDA of treatment (38℃ of yellowing) was lower than that of 42℃ of yellowing, but the peroxidase activity was higher. The level of lipid peroxidation was the lowest and the peroxidase activity was the highest when the comparative moisture of yellowing period was 80-85%.3.During the process of flue-curing, it was evident that the respirating rate decreased at the former stage of yellowing (0-12h),and increased to the peak in the middle of yellowing (about 30h after curing ),then decreased again in the latter stage of yellowing (30-36h). At color fixing period ,the respirating rate decreased to a very low level. The respirating rate decreased gradually with the loading density increasing under the same yellowing condition. The dry-weight loss of treatment (38℃ of yellowing) was smaller than that of treatment 42℃ of yellowing.4.The content of chlorophyll reduced in the whole course of curing, it decomposed slowly in earlier stage , then decomposed quickly in middle period , and slow down to stopping on later stage .The speed of decomposition of treatment 55-56 kg/m~3 was the fastest in four treatments under every yellowing condition.5.The activity of PPO decreased gradually in the process of curing, it was the highest by treatment (55-65)and the lowest by treatment (35-45) in four treatments of loading density. Under the same loading density , the activity of PPO was lower in treatment of 38℃ of yellowing and 80-85% comparative humidity. It showed that...