Effects Of Harvest Maturity And Curing Methods On Quality Of Dark Sun-Cured Tobacco In Jilin

Activities of enzyme and hormone in dark sun-cured tobacco during development and naturity process,activities of enzyme and internal components the tobacco of different curing methods during the curing process and effects of curing methods and harvest maturity on quality of dark sun-cured tobacco were studied to find the appropriate harvest maturity and curing methods so that to provide reference to develop an appropriate maturity standards and curing regulation for good quality dark sun-cured tobacco leaf in Jilin province from 2013 to 2014.The results are as follows:1.During development and maturity process in the upper leaves and middle leaves in dark sun-cured tobacco,the content of the pigment(chlorophyll a and chlorophyll b and carotenoids)was always decreasing and decreasing more severe after the B(C)M3;Activity of invertase decreased initially and then increased and decreased finally,which were all highest in the B(C)M3;Activity of amylase increased initially and decreased finally and the highest peak was in the B(C)M3;Activity of glutamine synthetase were all manifested as bimodal curve,and the highest peaks respectively was in the 30 day of leaf age and the B(C)M3;2.During the whole curing process of the upper leaves and middle leaves in dark sun-cured tobacco,The average environment temperature both day and night was in the order of: T3>T2>T1,on the contrary the average environment relative humidity both day and night was in the order of: T1>T2>T3.The content of the pigment(chlorophyll a and chlorophyll b and carotenoids)was always decreasing and the speed of decreasing was in the order of: T3>T2>T1;Activity of amylase,lipoxygenase and polyphenol oxidase increased initially and decreased finally and activity of amylase and lipoxygenase was always in the order of: T3>T2>T1,on the contrary activity of polyphenol oxidase was in the order of: T1>T2>T3.3.During the curing process of the upper leaves and middle leaves in dark sun-cured tobacco,The content of Free amino acid increased initially and decreased finally,and it was in the order of: T3>T2>T1;The content of polyphenols(chlorogenic acid,rutin and scopoletin)was increasing roughly,and the content of chlorogenic acid,rutin,scopoletin and the total polyphenols was in the order of: T3>T2>T1;The content of TSNAs was always increasing,and the content of NAT,NNK,NNN and the total TSNAs was in the order of: T3>T2>T1;The content of starch was always decreasing,and the speed of starch degradation was in the order of: T3>T2>T1.4.The increase of harvest maturity,the content of total sugar,reducing sugar and ratio of total sugar to nicotine increased gradually,starch decreased obviously in the upper leaves and middle leaves.The content of chlorine lowered after the first.The content of total nitrogen and nicotine were appropriate,and indifference between treatments.The content of potassium was low.Main chemical composition were more harmonious in B(C)M3.The contents of most of neutral aroma components and the total were all the highest in the leaves of B(C)M3 in the upper leaves and middle leaves.The single-leaf weight,stem ratio,filling power and leaf specific weight were better than others in the leaves of B(C)M3.The tobacco leaves were in B(C)M3 what were a great aroma quality and quantity,a decreased offensive odor and irritation,a moderate intensity,an appropriate aftertaste and combustibility.Its sensory quality was the best,and the leaves of B(C)M1 were the worst.The production,output value and high-class-leaf percentage in the leaves of M3 were the best and the leaves of M1 were the worst.5.The content of total sugar,reducing sugar,potassium,ratio of reductive sugar to nicotine and ratio of total nitrogen to nicotine in the tobacco leaves were the highest in the steely barn curing method(T3),where the content of starch,nicotine and chlorine were the lowest in the upper leaves and middle leaves in dark sun-cured tobacco;The contents of most of neutral aroma components,alkaline aroma components and the total of aroma components were all the highest in the leaves of the steely barn curing method(T3)in the upper leaves and middle leaves;The content of NAT?NNK?NNN?NAB and the total of the TSNAs were the lowest in the leaves of the steely barn curing method(T3),on the contrary it were the highest in the leaves of the traditional outdoor curing method(T1)in the upper leaves and middle leaves;In the upper leaves and middle leaves in dark sun-cured tobacco,the leaf length,leaf width,leaf area,single-leaf weight,stem ratio,and leaf specific weight of the steely barn curing method were better than others(T1,T2).The difference of filling power during the different treatments was small and they all were in the normal level;The tobacco leaves were in the steely barn curing method what were a great aroma quality and quantity,an appropriate concentration,strength and gray,In addition its total score of sensory quality also was the best;The production,output value and high-class-leaf percentage in the leaves of the steely barn curing method(T3)were the better than the leaves of yellowing covered plastic membrane—outdoor curing method and steely barn curing method.6.The results showed that the harvest maturity in B(C)M3 and the steely barn curing method was the appropriate methods to improve the quality of dark sun-cured tobacco in the upper leaves and the middle leaves in the county of Nongan in Jilin province.