The Distribution Of Organic Acid Contents Of Flue-Cured Tobacco In Different Ecological Regions And Their Relationship With Other Main Chemical Components

Organic acid, routine chemical compositions, polyphenol and volatile aroma components were determined by 87 flue-cured tobacco samples in 5 typical ecological locations in China, 13 flue-cured tobacco samples in Brazil, and 13 flue-cured tobacco samples in Zimbabwe. The distribution characters of the organic acid in different latitudes are discussed. The difference of the organic acid compounds was analyzed among different positions, different latitudes and different altitudes by methods of analysis of variance. And the relationship between organic acid compounds and routine chemical compositions, polyphenol and volatile aroma components were analyzed by methods of correlation analysis, cluster analysis, variance analysis and regression analysis. The results showed that:(1) The average total amount of flue-cured tobacco samples'organic acids was 11.42%, and compositions of malic acid (8.6%) was greatest, far more than other acids, which amounting to more than 75% of the total amount. Oxalic acid (1.04%), citric acid (0.64%) come next, the content of lactic acid is the lowest, only taking up to 0.04%. Lactic acid, acetylpropionic acid, malic acid, citric acid and organic acid had relative high coefficient of variation, great discreteness, and has an uneven distribution. Oxalic acid, malonic acid, palmitic acid, oleic acid and linoleic acid had a relative low coefficient of variation. Correlation analysis showed that the total amount of organic acid had positive correlation at the 0.01 level with oxalic acid, malic acid and citric acid content, had high positive correlation at the 0.05 level with linoleic acid + oleic acid, and had negative correlation with acetylpropionic acid. There was a greater relevance between organic acid substances.(2) There existed significant differences among different tobacco-growing areas, various positions and different latitudes for the organic acid content of flue-cured tobacco, but no difference among various elevations. Indicating the trends of Guizhou> Luyu > Yunnan > Zimbabwe >Northeast > Brazil> Fujian. The content of tobacco leaf's organic acid in different parts manifest as low part (13.4%)> middle part (10.41%) >high part (10.30%). The difference of organic acid content between high part and middle part is not very obvious, but the contents of these two parts are significantly lower than low part. The content of organic acid in tobacco leaf's in different latitude manifest as Mid-latitude (12.44%) > low-latitude (11.30%) > high-latitude (9.97%). The content of organic acid in high-latitude is remarkably lower that of mid-latitude, but there is no obvious difference between the content of organic acid in high-latitude tobacco leaf and that of mid-latitude and high latitude leaves. The content of tobacco leaf's organic acid in different altitudes manifest as mid-altitude (12.82%) > high-altitude (11.64%) > low-altitude (10.72%).(3) The relationship analysis between routine chemical compositions and organic acid showed that total organic acids had a significant negative correlation with the content of total sugar and reducing sugar and had negative correlation with potassium and potassium-chlorine ratio and very significantly positive correlation with nitrogen-nicotine ratio. And had a relatively significant correlation with organic acid and routine chemical compositions. Total organic acids content of flue-cured tobacco were divided into three groups of low, medium and high by cluster analysis and the analysis of corresponding routine chemical compositions showed that the nicotine content, total sugar content, reducing sugar content, potassium content and potassium-chlorine ratio decreased, total nitrogen content and sugar-nicotine ratio increased and chlorine content first decreased then increased with the increasing of organic acid. The differences of total sugar, potassium, chlorine content and potassium-chlorine ratio of three groups of organic group were very obvious. Reducing sugar content of three groups of organic group was very obvious. There existed no differences in three groups of nicotine content, total nitrogen content, sugar-nicotine ratio and nitrogen-nicotine ratio. The results of regression analysis showed that nicotine and potassium had a great impact on organic acid content.(4) The relationship analysis between organic acid and polyphenol content showed that, total organic acids had very significantly positive correlation with neochlorogenic acid and quinic acid, had very significantly negative correlation with scopoline, and had significantly positive correlation with scopoletin. The matters of organic acid are highly correlated to polyphenol. According to organic acids content of flue-cured tobacco, polyphenol content were divided into three groups of low, medium and high by cluster analysis. The analysis of corresponding polyphenol content indicated that neochlorogenic acidcontent, quinic acid content, scopoletin content and rutinoside content increased, scopoline content decreased, chlorogenic acid and rutin showed the tends of first increased and then decreased with the increase of organic acid. There existed significant differences among new chlorogenic acid, quinic acid and scopoline content in three groups, but no significant differences for other polyphenol content.(5) The relationship analysis between organic acid and volatile aroma components showed that, total organic acids had a significantly negative correlation with furfural, and had a significantly positive correlation with phenylacetaldehyde. There existed significant relationship between matters of organic acid and volatile aroma components. According to organic acids content of flue-cured tobacco, neutral aroma content were divided into three groups of low, medium and high by cluster analysis. The analysis of corresponding neutral aroma content The analysis of volatile aroma components in these three corresponding groups shows that, with the increase of organic acid, furfural content, benzaldehyde and solanone content decreased, phenylacetaldehyde content increased and other neutral aroma components showed the trend of first increased and then decreased. There existed signifcant differences among three corresponding groups of benzaldehyde content, phenylacetaldehyde content while no significant differences for other neutral aroma matters.