The Quality Characteristics And Effects Of Harvest Maturity On Quality Of Dark Sun-cured Tobacco In Guangchang

In order to clarify the current qualitative characteristics of dark sun-cured tobacco and explore the existing problems,Guang Chang sun-cured tobacco was studied by analysing the appearance quality,physical characteristics,chemical composition and sensory quality of different grade and different leaf of the sun-cured tobacco in Guang Chang.In 2015,we did an experiment to study the changes of chemical composition during air-curing and the effect of harvest maturity on the physical characteristics,chemical composition,neutral aroma components and sensory quality of the air-cured leaf to clarify the appropriate harvest maturity for the sun-cured red tobacco in Guang Chang.The results are as following:1.The qualitative characteristics of sun-cured red tobaccoAppearance quality: The sun-cured tobacco have dark,glossy leaf with loose structure,enough oil content and a bit thick and poor integrated for most leaves.As the descending of the tobacco grade,the leaf become thinner,and have less oil contents,light color.The integrity is reduced.The second and third grade tobacco have the best appearance.Physical characteristics: Smaller leaf,the stem ratio and single leaf weight and filling value are low,the leaf weight of unit area and thickness and tension are larger.As the descending of tobacco grade,the leaf weight of unit area,tension,filling value gradually decreased.The size of leaf and single leaf weight increase after the first decrease,and the stem ratio of leaf decrease after the first increase.In generally,the level 2 tobacco is best.Chemical composition: The content of total sugar,reducing sugar,total nitrogen and total phenol are low but the content of nicotine,potassium and chlorine are high.The difference of total sugar and reducing sugar content in different levels are smaller.As the descending of tobacco grade,the content of nicotine,total nitrogen and total phenol gradually decrease,but the content of potassium and chlorine gradually increase.Through the statistical analysis,there is some differences for the content of chemical composition between different township.The content of total sugar,total nitrogen and potassium have a smaller difference.The largest difference of chemical composition content between different township is chlorine.Neutral aroma compounds: The upper leaf have the highest content of neutral aroma compounds.And the content of neutral aroma compounds gradually decrease along with the part decreasing,the content of phenylalanine and neophytadiene are lower.The content of neutral aroma compounds gradually decrease along with the grade decreasing,the highest level of the content of neutral aroma compounds is level 1.Sensory quality: The sun-cured tobacco in Guang Chang have more undesirable soil,irritancy and impact are strong,and butter combustibility,but the quality and quantity of aroma are ordinary.The sensory quality of middle leaf are best.To different grades,the sensory quality of level 2 is the best.2.The effect of harvest maturity on the quality of sun-cured tobaccoPhysical characteristics: Improving the maturity of tobacco leaf can decrease the single leaf weight,leaf thickness and increase the filling value.The stem ratio of leaf decrease first an then start to increase as the improving of the degree of maturity.The tension of leaf increase first an then start to decrease as the improving of the degree of maturity.Chemical composition: As the degree of maturity of tobacco leaf improving,the content of total sugar,reducing sugar and potassium increase first and then start to reduce.And the content of nicotine gradually increase,but the content of chlorine gradually decrease.The chlorophyll and the carotenoid also decrease gradually.Neutral aroma compounds: The content of neutral aroma compounds increase first and then start to descrease with the increasing of the maturity degree.The leaf color become yellow when the degree of maturity of tobacco is about 50%.At this moment,the content of neutral aroma compounds is hightest.Sensory quality: Improving the maturity of tobacco leaf can improve the quality and quantity of aroma,aftertaste and so on.and reduce the undesirable soil and decrease the irritancy and impact.Improve the combustibility of the leaf.And it can significantly improve the smoking total scores.