Quality variations of cut tobacco cured by infrared-convection cylinder drying

ObjectiveQuality variations of cut tobacco cured by infrared-convection cylinder drying were investigated to provide basic theoretical basis and technical supports for exploring the new drying methods and techniques for tobacco raw materials.MethodChongqing C041 cut tobacco in 2015 was used as material.It was dried by self built far infrared-cylinder dryer.The effects of infrared-convection drying process on moisture content,surface temperature,elasticity,fil-ling value,pore volume and structure of cut tobacco were investigated.The results were compared with those in the tradi-tional drying.In addition,variations of pore size distribution of cut tobacco in infrared-convective drying process were ex-plored.ResultIncreasing the infrared radiation temperature and hot air temperature during infrared-convection drying could strengthen the effects.The filling value of tobacco rose with the increase of infrared radiation temperature,and de-creased with the increase of hot air temperature. The increase of the hot air increased the elasticity of tobacco.When the infrared temperature was 170℃,the elasticity was the largest,and when the temperature was 145℃the elasticity was the lowest.Pore volume of the tobacco enhanced with the increase of infrared temperature and the decrease of hot air tempera-ture.During the drying process,the proportion of pore volume changes was concentrated in the range of 0.50-20.00 and 0.05-0.50μm.Comparing on two different drying methods,it was found that filling value and pore volume of cut tobacco cured by infrared-convection drying were greater than those cured by traditional drying,and their elasticity was small, and degree of fragmentation was high.ConclusionWithin a certain range,improving infrared radiation temperature,re-ducing hot air temperature are beneficial to maintain filling value of cut tobacco,and pore volume also changes regularly. Compared with traditional drum drying,the drying rate of infrared-convection drying is faster,hence it should be applied in the actual drying process of cut tobacco.