Abstract:

To explore the degradation characteristic of the plastid pigment of the ‘KRK26’ leaves from Yunnan tobacco-growing area during flue-curing, providing a reference for the assessment of the aroma quality and the optimization of the flue-curing parameters of the tobacco variety. The category, contents and the content correlations of the degradation products of the plastid pigment of the middle part leaves of the Zimbabwe tobacco variety ‘KRK26’ from Yuxi tobacco-growing area of Yunnan Province during three phase flue-curing were studied on the basis of Gas chromatography (GC)-Mass spectrum (MS) analysis. The results indicated that, during the flue-curing, 11 main degradation products of the carotenoid (Car) and 3 of the chlorophyll (Chl) were detected. The highest contents of β-damascenone, β-damascone, dihydroactinodiolode, megastigmatrienone 1, 2, 3, 4, farnesylacetone and solanone were all at the stem-drying, those of 3-hydroxyl-β-damascone and 3-keto-α-ionol at the early period of the color-fixing, and those of pyrroles, neophytadiene and furans at the early period of the yellowing, the later period of the color-fixing and the middle period of the yellowing respectively. The content differences of the different degradation products of the Car and Chl and the difference of the degradation product contents of the Car at the different flue-curing stages all reached the extremely significant level, but the difference of the product contents of the Chl at the different stages did not reach the significant level. Extremely significant, significant and non-significant positive correlations or significant and non-significant negative correlations were found among the contents of the degradation products of the plastid pigment. The predominant degradation products of the Car at the different stages were all mainly solanone, total megastigmatrienones, farnesylacetone and β-damascenone and the predominant product of the Chl was neophytadiene whose content percentages in the total quantities of the main degradation products of the Car and the plastid pigment were more than 94.0% and 89.8% respectively all the time. So, the chief materials determining the aroma quality of ‘KRK26’ were neophytadiene, solanone, total megastigmatrienones, farnesylacetone and β-damascenone.