Changes of Free Amino Acids in Burley Tobacco with or Without Casing During Roasting

The changes of free amino acids in burley tobacco with or without casing during roasting was studied by reverse phase high performance liquid chromatography with precolumn derivatization with o-phthalaldehyde and fluorenylmethyl chloroformate.The results showed that:1) the total amount of free amino acids in burley tobacco without casing increased first and then decreased in the process of roasting,and it decreased by 19% after tobacco was roasted for 18 minutes,and the contents of Asn,Asp and Arg decreased by more than 20%;2) for burley tobacco with casing,the total amount of free amino acids reduced gradually during roasting,and it decreased by 37% after tobacco was roasted for 18 minutes,and the contents of Glu and Phe decreased by more than 50%,Asn and Val decreased more than 40%,and Asp,Ser,Arg,Lys and Pro decreased more than 30%;3) the change of free amino acids in burley tobacco with or without casing mainly occurred at 140℃.