Studies On Dynamic Changes Of Major Chemical Compositions Of The Leaves Of LLBC And HPBC Of Flue-cured Tobacco

The change of major chemical compositions of tobacco leaves is veryimportant for the formation of chemical superior quality during curing process, ifeach major chemical composition of tobacco leaves is too excessive or too few, it willbring a disadvantageous influence for the quality of smoke gas. Therefore, a variety ofchemical compositions in balance and harmony will be very important for the smokegas. This paper studied on dynamic changes of major chemical compositions, such asstarch, total sugar, reducing sugar, total nitrogen and protein, of loose leaves bulkcuring (LLBC) and hang pole bulk curing (HPBC) of flue-cured tobacco. By studiedthe change law of each composition, for discuss how establish a optimal arts andcrafts of curing. By regulate and control the change of physiology and biochemistry oftobacco leaves, for making the content of each chemical composition can achieveoptimum target aim, and achieving the optimal combination. Results of studiedshowed that:1. In the process of curing, water contents of different parts of leaves of LLBCand HPBC are very high in the beginning, and dehydrated slowly. From thepreliminary curing to the 48 hour of curing time, the average speed of moisturediminishing slowed. After the 48 hour, dewatered speed become more rapid, andmade the hydrofuge and colour stting move faster. The dewatered speed of tobaccoleaves reach fastest when between 48 hour and 60 hours of curing and between 60hours and 72 hours of curing.2. The change of starch content of leaves mostly happened in processes ofyellowing and colour stting. In the in process of LLBC and HPBC, the degradation ofstarch mostly concentrated in 36 hours in the process of curing, and it became slowdown between 36 hours and 60 hours, and it became slowness when after 72 hours.Compare the starch content of different parts of leaves, we found: lugs＜cutters＜leaf.The time of loose leaves bulk curing was so longer, therefore the starch content ofloose leaves bulk curing is lower than hang pole bulk curing. 3. The different bulk curing method in the process, the total sugar contentshowed itself a trend of sustained rose along with the change of times. When cured to72 hours, the total sugar content of HPBC reached maximum. The total sugar contentof LLBC reached maximum when cured to 96 hours. At the end of curing, reached aconclusion: leaf＞cutters＞lugs. The time of LLBC experiences long, thereforeroasts after the total sugar content to be higher.4. During the process of curing, reducing sugar content of different bulk curingmethod showed itself a trend of sustained rose along with the change of times. Whencured to 72 hours, the reducing sugar content of different parts of leaves of HPBCreached maximum, and reducing sugar contents of the cutters and leaf return tomaximizing when bakes to 96h. compared reducing sugar contents of different parts ofleaves, we found: leaf＞cutters＞lugs. After bakes had finished, the sugar content ofLLBC is higher than HPBC.5. During the process of curing, total nitrogen content of different parts of leavesdecreased gradually and showed itself a trend of sustained descending along with thechange of times. Compare the total nitrogen content of different part leaves ofHPBC, we found: lugs＜leaf＜cutters. Compare the total nitrogen content ofdifferent part leaves of LLBC, we found: lugs＜cutters＜leaf.6. The different bulk curing method in the process, the degradation of protein wasrather slow for incipient curing, the protein degraded with great speed and heavy losswhile it cured to 24 hours. After the colour stting, the degradation declined graduallyagain and with less loss. It showed the change law of "slow to fast to slow". Comparethe starch content of different parts of leaves, we found: leaf＞cutters＞lugs. TheLLBC protein degeneration process is longer than HPBC, and LLBC cured after theprotein content to be also lower than HPBC.7. During the process of different bulk curing method, the free amino acidcontent of tobacco leaf has increase correspondingly along with the decrease of theprotein content, and it has a great change in three days. At the end of curing, comparethe free amino acid content of different parts of leaves, we reached a conclusion: leaf＞cutters＞lugs.8. The schmucks number of different part leaves of HPBC respectively is: 2.2 forlugs, 2.0 for cutters and 2.1 for leaf. The schmucks number of different part leaves ofLLBC respectively is: 2.4 for lugs, 2.1 for cutters and 2.2 for leaf. Compare the cured leaves of LLBC and HPBC, the starch content of cured leaf of LLBC was sinlificantlylower than that of cured leaf of HPBC, the total sugar and reducing sugar content ofcured leaf of LLBC was sinlificantly higher than that of cured leaf of HPBC. Thisresult showed that the quality of cured leaf of LLBC was better than that of cured leafof HPBC.