The Relationship Between Main Non-volatile Organic Acid Metabolism And Quality Of Flue-cured Tobacco

12 flue-cured tobacco varieties from Xuchang tobacco growing areas were used as experimental material.The dynamic changes of total organic acid content,malic acid content,citric acid content,metabolism related enzymatic activity,the nicotine content and sensory quality of modulated smoke sample were determined.At the same time,the grade of B2 F and C3 F leaf samples were collected in seven maintobacco growing areas of Henan,Shandong,Shanxi,Anhui,Guangdong,Yunnan,Guizhou,being analyzed and evaluated the total content organic acid,appearance quality,chemical components,sensory quality index.In order to clarify the variation and relevance of main non-volatile organic acid concentrations and metabolism related enzymatic activities in the process of the growth of flue-cured tobacco leaves.And tc analysis and evaluat the differences among appearance quality and conventional chemical composition and sensoryquality of tobacco planting areas.And to investigate the effect of the ratio of total organic acid contents and the nicotine contents("acid-base ratio")of tobacco leaf quality.The results showed that:(1)With the growth of tobacco plants,flue-cured tobacco total organic acid content indicated a trend of first increased then decreased,in the middle of leaf age50d-60 d reached the highest value.The total organic acid contents of different flue-cured tobacco varieties middle leaves had significant differences in different age periods while had little changes before and after modulation.(2)Malic acid contents had a trend of gradually growth.Citric acid contents displayed a slow "increase-decrease" trend.Malic acid contents and the MDH activity had a significant negative correlation.Citric acid contents and the CS activity had a significant positive correlation,while had little correlation with the NAD-IDH activity.(3)When the total organic acid contents was more than 32%,nicotine contents was between 1.5% and 2.6% at the same time,the higher "acid-base ratio1’ the better sensory quality of flue-cured tobacco.In summary,the accumulation of malic acid and citric acid of flue-cured tobacco leaf were regulated by the changes of its metabolism related enzymatic activity." Acid-base ratio " influenced the smoke mildness of flue-cured tobacco.Through regulating NAXJ-MDH and CS activity to adjust the content of malic acid and citric acid,coordinating Macid-base ratio" and improving the quality of tobacco.(4)There were significant differences of flue-cured tobacco non-volatile organic acid contents among leaf parts and areas and varieties.The total variance of non-volatile organic acid contents in flue-cured tobacco showed that leaf position >original areas >varieties.The total variance of non-volatile organic acid contents in upper leaves was greater than middle leaves.While the average non-volatile organic acid contents in upper leaves was less than middle leaves.It was necessary to distinguish leaf positions for researching non-volatile organic acid contents of flue-cured tobacco.The ecological effect on the non-volatile organic acid contents of flue-cured tobacco was greater than varieties.(5)We used the statistical software SPSS to study organic acid contents,nicotine contents,"acid-base ratio" and appearance quality,chemical components,sensory quality of simple correlation and stepwise regression analysis of flue-cured tobacco middle leaves.The results showed that non-volatile organic acid contents had a significant positive correlation with soft fineness and combustibility.However,leaf structure,flexibility,total nitrogen contents,protein and ^reducing sugar/total sugar "were the main factors influencing organic acid contents.The nicotine contents had a significant positive correlation with stimulating.While,maturity,leaf structure,appearance quality score and total nitrogen contents were the main factors influencing the nicotine contents.MAcid-base ratio" had a significant negative correlation with stimulating.While chroma,"total nitrogen/nicotine" were the main factors influencing "acid-base ratio".(6)Flue-cured tobacco could have a suitable "acid-base ratio’*.The most suitable Macid-base ratio" 1 range was different in different leaf parts.Because of the flavor styles,the most suitable Hacid-base ratio1’ range could vary slightly.On the upper leaves of flue-cured tobacco,when the non-volatile organic acid contents was between 35%~60%,and at the same time the nicotine contents was between2.5%-3.5%,the higher riacid-base ratio " the better sensory quality.As in middle leaves of flue-cured tobacco,when the non-volatile organic acid contents was between 25%-65%,and at the same time the nicotine contents was between2.0%-3.5°/〇,the higher " acid-base ratiof,the better sensory quality.