Curing Characteristics Of Shandong Main Cultivated Tobacco Varieties And NC55Bulk Cuirng Technology Research

Tobacco curing characteristics is an important impact factor on the quality of tobacco leaf，domestic and abroad have attached great importance to the study of tobacco curing characteristics.Different flue-cured tobacco varieties have different curing characteristics, every year due to the lack ofunderstanding of the tobacco curing characteristics, resulting in a large number of bad curing tobaccoleaves appeared, causing serious economic losses. In addition, with the continuous promotion ofbulk-curing barn in recent years, the percentage of bulk-curing is increasing,the research on bulk curingtechnology is not sufficient, every year because of the bulk-curing technology is not perfect and lesstargeted, result in green and variegated tobacco leaf，smooth，oil shortage, closely structure, chemicalcomposition coordination of cured tobacco，reducing the quality and availability of tobacco leaf，it’sdifficult to meet the tobacco material demand of “Chinese style cigarette".Aimed at ShanDong tobaccovarieties this study carried out two part experiments, one part is the research on curing characteristics ofdifferent position leaves of NC55,ZhongYan100,K326of Shandong main cultivated varieties, whichproviding the basis for formulating precise bulk curing technologies to different varieties; another partis the research on optimizing and improving the bulk curing technology of NC55cutter leaves, forminga suitable bulk curing technology for NC55cutter leaves, improving the comprehensive characters ofcured tobacco.The main research conclusions were as follows:1. The curing characteristics of different positions and three different varieties:NC55: lower leaves: The speed of chlorophyll degradation is fast, the yellowing characteristics isgood,water loss show good balance between yellowing stage and color fixing stage, water dehydratingcharacteristics is good, ppo activity in early curing stage is high, but ppo activity is relatively low inbrowning reaction sensitive period, relatively speaking,the lower leaves show better curingcharacteristics; cutter leaves: Chlorophyll degradation speed is little slower than ZhongYan100,chlorophyll degradation showed balance between yellowing stage and color fixing stage,the yollowingcharacteristics is good, the water loss balance between yellowing stage and color fixing stage is notgood, the leaves loss too much water at early stage, water dehydrating characteristics is good, the levelof ppo activity and polyphenol content is higher, the leaf coloring characteristics is common, so thecuring characteristics are common. Upper leaves: Chlorophyll degradation speed is relatively slow, theyollowing characteristics is not good, the leaves loss too much water at early stage, the water loss rate isfaster, the water loss balance between yellowing stage and color fixing stage is not good,result in theuncoordinated between the water loss and the yollowing,the level of ppo activity and polyphenolcontent is higher during curing,the leaf coloring characteristics is not good，so the curing characteristicsis bad.ZhongYan100: lower leaves: The speed chlorophyll degradation is more slowly than variety NC55,the yellowing characteristics is common, the leaves loss too much water at early stage, the water lossrate is faster, the water loss balance between yellowing stage and color fixing stage is not good, ppo activity is relatively low during curing,the lower leaves curing characteristics are common; cutter andUpper leaves: The speed of chlorophyll degradation is fast, the yellowing characteristics is good,thewater loss balance between yellowing stage and color fixing stage is good,water dehydratingcharacteristics is good, the level of ppo activity and polyphenol content during curing is low, the leafcoloring characteristics is good, so the curing characteristics is good.K326: Compared to variety NC55and ZhongYan100, three different positions tobacco leaves ofvariety K326have the same performance:The speed chlorophyll degradation is slowly during earlycuring stage, the speed is fast during later curing stage,the tobacco leaves need long time to turn totalyollow under dark condition,the yellowing characteristics is not good, the leaves loss too less water atearly stage,at later stage the leaves loss too much water and the water loss rate is faster, the water lossbalance between yellowing stage and color fixing stage is not good, so the water dehydratingcharacteristics is not good, the level of ppo activity and polyphenol content during curing is higher, sothe curing characteristics is bad.2. the optimized bulk curing technology to variety NC55cutter leavesAiming at cutter leaves of variety NC55, on the basis of conventional three-step-curing technology,forming the precised technology suitable for variety NC55cutter leaves,the key operationpoints:leaf-changing stage, dry-bulb and wet-bulb temperature is38℃/37℃, keep stable time is24to30hours, the leaves turning70to80persent yellow and soft; wilting stage, dry-bulb and wet-bulbtemperature is42℃/39～37℃, keep stable time is18to24hours, the leaves turning90to100persentyellow and the viens turn soft, muscle-yellowing stage, dry-bulb and wet-bulb temperature is47℃/37～38℃, keep stable time is18to24hours,the leavesand muscle total yollowing,the leaves1/3dried;leaf-drying stage, dry-bulb and wet-bulb temperature is54℃/40℃, keep stable time is12hours, theleaves total dried,vein-drying stage, dry-bulb and wet-bulb temperature is65℃/42℃,keep stable time tothe vein dried.