Effect of ecological environment on upper stalk leaves quality and neutral aroma components of burley tobacco

To explore the effects of ecological environment on the quality of burley tobacco during air-curing process, burley leaves cultivated in Binchuan and Yunlong Counties of Yunnan Province were put into both counties for air-curing, respectively. Temperature and relative humidity of barns were investigated during the curing process. HPLC and GC/MS were used to analyze plastid pigment and neutral aroma components of burley tobacco leaves. Results showed no apparent differences in temperature between the two areas. However, the differences in relative humidity between the two areas were very significant. Relative humidity in Yunlong County was higher by 4.42%~16.54% than in Binchuan County throughout the air-curing process. Air-curing duration of tobacco leaves in Binchuan County was 9 days shorter that in Yunlong County. The differences in leaves cured in the two ecological environments were evident in terms of physical appearance and internal quality. β-carotenoid of leaves cured in Binchuan County produced in Yunlong County was 6.44% higher than that produced in Binchuan County, while β-carotenoid contents in leaves cured in Yunlong County produced in Binchuan County was 14.45% higher than that produced in Yunlong County. Neutral aroma components of leaves cured in Yunlong County was higher than that of leaves cured in Binchuan County. Leaves produced in the two counties and cured in Yunlong County respectively had 47.31% and 20.37% higher aroma components over those cured in Binchuan County. For leaves produced in the same area but cured in Binchuan County had significantly more contents of nicotine and total sugar than those cured in Yunlong County. However, the contents of total nitrogen of leaves cured in Yunlong County were significantly higher than those cured in Binchuan County. Strong correlations were noted between eco-environment and the contents of plastid pigment, neutral aroma components and the main chemical compositions of burley tobacco. It was therefore significant to make reasonable scientific measures based on local situations during curing process in order to increase the content of aroma and improve the quality of leaves in agricultural and manufactured burley tobacco.