Comparison of contents of free and glycosidic neutral aroma components in four different tobacco types

The SDE-GC/MS(Simultaneous distillation extraction-GC/MS) method was used to analyze the contents of free and glycosidic neutral aroma components in cured leaves of 4 tobacco types(flue-cured,burley,oriental,and sun-cured tobaccos) produced in Sichuan Province.The results showed that all the 4 tobacco types had free and glycosidic aroma components.The total amount of free neutral aroma components followed the order of flue-cured tobacco burley tobacco sun-cured tobacco oriental tobacco.In flue-cured tobacco,neophytadiene accounted for a large proportion,so the content of total free aroma components excluding neophytadiene was the highest in sun-cured toba-cco and oriental tobacco,followed by burley tobacco,then lowest in flue-cured tobacco.Solanone content was the highest in oriental tobacco among the 4 types with the greatest proportion in total aroma fraction.The total amount of glycosidic neutral aroma components in flue-cured tobacco was the highest,followed by sun-cured tobacco,burley tobacco and oriental tobacco.In addition,the content of total glycosidic aroma components excluding neophytadiene and the ratio of glycosidic to free aroma components in flue-cured tobacco were the highest,and there was no significant difference among the other 3 tobacco types.The aroma components found both in free and glycoside forms in the 4 tobacco types were those making great contribution to tobacco leaf aroma;the proportion of glycoside form to free form of these neutral aroma components were different among the 4 tobacco types.Neophytadiene and furaldehyde mainly existed in free form,while megastigmatrienone mainly existed in glycoside form in flue-cured tobacco,which had great variation in the sun-cured tobacco and air-cured tobacco.Solanone mainly existed in free form,which was dominant in the oriental tobacco.