Relationship between Chemical Components, Volatile Aroma Metabolites and Sensory Quality of Tobacco Leaves from Three Tobacco Areas in Yunnan

Purpose To clarify the sensory differences of sweet-scented flue-cured tobacco in different tobacco-growing areas of Yunnan, and to analyze the correlation among chemical components, volatile aroma metabolites and sensory quality, identifying the key substances affecting aroma, style characteristics and quality formation.

Methods C3F grade tobacco leaves from three tobacco-growing areas in Yunnan (Honghe, Puer, Qujing, denoted as HH, PE, QJ, respectively) were selected. Sensory evaluation and gas chromatography-mass spectrometry (GC-MS) were used to explore the chemical components and volatile metabolites of tobacco leaves, and their correlations with sensory indicators were analyzed.

Results There were significant differences in sensory quality, chemical components and volatile aroma substances of flue-cured tobacco among the three areas. Sensoryly, HH had prominent sweet aroma and the best sensory quality; PE had strong miscellaneous gas and irritation; QJ had poor aroma quality but light miscellaneous gas. In terms of chemical components, except for reducing sugars, there were extremely significant differences in total sugar, nicotine, total nitrogen, total potassium, sugar-alkali ratio and nitrogen-alkali ratio among the three tobacco areas, and the sugar-alkali ratio in all three areas was greater than 10. A total of 581 volatile metabolites were identified, mainly esters and heterocycles, among which citronellal and methyl acetate were key substances affecting sensory quality and style characteristics. Correlation analysis showed that total potassium of QJ was positively correlated with aroma expression, while reducing sugar, etc. were negatively correlated with concentration; lactic acid of PE was positively correlated with poor sensory indicators, while reducing sugar, etc. were negatively correlated with positive sensory indicators; total nitrogen, etc. of HH was positively correlated with concentration, strength, aroma expression and other indicators.

Conclusion There are significant differences in the quality of sweet-scented flue-cured tobacco in different tobacco-growing areas of Yunnan, among which flue-cured tobacco from Honghe has the best comprehensive performance. Volatile components such as citronellal are key substances affecting the sensory quality and style characteristics of sweet-scented flue-cured tobacco in Yunnan.