A comprehensive understanding of changes which are induced in the composition of amino acids in tobacco leaves during curing is indispensable for the quality control of tobacco leaves, since amino acids are amongst the key components relating to the aroma/taste of cigarette smoke. This study is intended to elucidate the effect of curing conditions and tobacco leaf types on the dynamic profiles of amino acids induced during curing.

Flue-cured Virginia (FCV) and Burley (BLY) were cured with two methods, a JT typical barn or a modified barn, in which the temperature and humidity of air were each kept at a constant value (38 °C and 85%R.H.), the same as FCV yellowing conditions. A proportion of the cured leaves was taken out of the barn at fixed intervals during the curing to measure their amino acid profiles. Amino acids were extracted with H₂O/Methanol solution, and this was followed by a quantitative analysis with a CE-ESI-MS system.

Induction patterns of amino acids were dependent on curing conditions, and amino acid profiles showed significant differences between FCV and BLY type leaves, even though these samples were treated under the same curing conditions. Proline and asparagine are known to be high volume components of the cured FCV and BLY type leaves, respectively. Dynamic ranges of these amino acids were completely different between FCV and BLY, while the induction patterns of both amino acids had similar tendencies throughout the curing process. The other metabolites and/or leaf types, such as Oriental leaf, should be analysed in the future to support a more precise interpretation of amino acid induction.