INFLUENCE OF CYSTEINE OXIDATION ON THERMAL FORMATION OF MAILLARD AROMAS

Cysteic acid and cysteinesulfinic acid, which are oxidized forms of re duced cysteine, were heated separately with D-glucose in an aqueous sy stem of pH 6 at 160 degrees C for 2 h. The reaction products were extr acted and analyzed. Among the identified compounds, pyrazines and fura ns are the most predominant compounds and no or only trace amounts of sulfur-containing compounds were identified in these two reaction syst ems. In the same reaction condition, the reduced cysteine and D-glucos e produced mainly sulfur-containing compounds; no pyrazines were found in this system. The reaction mass of cysteic acid and D-glucose posse ssed smoky, nutty, and yeasty aromas, while cysteinesulfinic acid with D-glucose generated a strong coffee note. The reduced cysteine with g lucose produced onion and garlic, as well as slightly meaty and sulfur y, flavors.