VOLATILE MINOR ACIDS IN COFFEE .1. CONTENTS OF GREEN AND ROASTED COFFEE

The contents of volatile acids, except for formic and acetic acids, ha ve been determined in green and roasted coffee by means of SDE, ion ex change and GC/FID. Identificated with GC/MS, for the first time in gre en coffee are 2-methylpropanoic, (S)-2-methylbutanoic, 3-methylbutanoi c, hexanoic, 3-methylpentanoic, heptanoic, octanoic, nonanoic, decanoi c, dodecanoic, tetradecanoic, pentadecanoic, (E)-2-butenoic, 2-methylp ropenoic, (E)-2-methyl-2-butenoic and 3-methyl-2-butenoic acids, in ro asted coffee 3-methylpentanoic, 2-ethylhexanoic, dodecanoic, tetradeca noic and pentadecanoic acids. All these acids, including propanoic, bu tanoic and pentanoic acids, were quantitated in green (as far as possi ble) and roasted coffee, partially for the first time. The found conte nts are much lower than most of the literature values. Most of the con tents increase with increasing degree of roast, but those of the highe r straight-chain saturated fatty acids, except for decanoic acid, do n ot. During storage at higher temperatures or/and high water contents, the contents of almost all the acids increase. The contents of some ac ids in roasted coffee are lower after steam treatment of the correspon ding green coffee.