【摘要】 为提升烟叶打叶复烤加工质量、降低复烤过程片烟收缩,以烤烟上部橘黄二级烟叶(B2F)和中部橘黄二级烟叶(C2F)打后片烟为材料,采用机器视觉装置并结合数字图像分析法,对片烟收缩特性进行检测和表征,对干燥过程片烟收缩特性进行分析,并探讨了烟叶原料部位、打后尺寸对片烟干燥收缩特性的影响。结果表明,图像分析法用于片烟收缩特性测试具有较好的精确性,一定条件下片烟收缩率测试结果的相对标准偏差低于6%。干燥过程中片烟收缩形变主要来源于干燥前期的快速脱水阶段,随着干燥过程含水率的降低,片烟收缩率变化趋缓。C2F的收缩率明显高于B2F,实际复烤干燥加工热风温湿度和终点水分下,C2F、B2F收缩率分别达14.3%、11.9%。不同尺寸片烟收缩特性存在差异,B2F片烟收缩率随尺寸增加而明显增大。可见,对于不同等级部位烟叶原料,通过复烤前片烟打叶尺寸的调节和复烤过程适当降低脱水速率,可有效控制收缩形变。更多还原

【Abstract】 In order to decrease the drying shrinkage of tobacco laminas and improve the processing quality of threshing and redrying,flue-cured yellow tobacco leaves of B2F and C2F after threshing were used as the test materials to measure and characterize the drying shrinkage of tobacco laminas by machine vision and digital image analysis.The variation of tobacco lamina shrinkage during drying was analyzed,and effects of raw materials parts as well as its size on shrinkage rate were also investigated.The results showed that image analysis method had a high accuracy for shrinkage rate measurement of tobacco lamina,and the RSD was less than 6%.During drying process,the shrinkage mainly occurred at the primary stage of drying,and shrinkage rate of tobacco lamina slowed down with the decreasing of moisture content.The shrinkage rate of middle tobacco leaves C2 Fwas higher significantly than that of upper tobacco leaves B2F.At the actual redrying processing conditions,the shrinkage rates of C2F and B2F reached 14.3% and11.9% respectively.Raw materials size also had significant effect on the tobacco lamina shrinkage characteristic.For upper tobacco leaves B2F,the shrinkage rate increased significantly with the increasing of tobacco lamina size.It can be seen that the shrinkage rate can be controlled by adjusting tobacco lamina size before redrying and decreasing the dehydrating rate during redrying for tobacco leaves of different grades and parts.更多还原