Determination of free fatty acids and their ethyl esters in musts and wines

White must and wine fatty acids are present mainly in the free form, or esterified as ethyl esters, and both contribute to flavor and foam properties of wine. A reliable and sensitive analytical procedure for analyzing the free fatty acids (C6-C18) and their ethyl esters has been developed. Sulfuric acid (3%) in methanol was selected as a derivative reagent, and optimal derivatization conditions were established (3 h at room temperature). This reagent gives total methylation of fatty acids and partial transesterification of ethyl esters to methyl esters and, through the study of this transesterification, free and bound fractions were determined satisfactory. (C) 1997 Elsevier Science B.V.