Abstract: In this study, orthogonal array design was employed to optimize thermal reaction conditions for the preparation of coffee flavor. This was followed by reaction product analysis by gas chromatography-mass spectrometry (GC-MS).When the reaction system was composed of 5 g of amino acids, 4 g of reducing sugar, 100 g of propylene glycol, 10 g of 95% ethanol and 40 g of deionized water at pH 6－8, the optimal reaction conditions were glucose/fructose ratio of 1: 1.5, arginine/lysine ratio of 2.5: 1, reaction temperature of 115 ℃, and reaction time of 4.5 h. The reaction resulted in the generation of 25 volatile flavor compounds such as furfuryl alcohol, maltol, dimethyl pyrazine, acetyl pyrrole and mercaptans. Moreover, pyrazine, pyrrodine, furan, phenol and their substitutes were the major volatile flavor compounds.

Key words: coffee flavor, thermal reaction, Maillard reaction, gas chromatography-mass spectrometry (GC-MS)