AMMONIA AFFECTS MAILLARD CHEMISTRY OF AN EXTRUDED AUTOLYZED YEAST EXTRACT - PYRAZINE AROMA GENERATION AND BROWN COLOR FORMATION

The effect of ammonia was studied by extruding mixtures of autolyzed yeast extract, glucose, and ammonium bicarbonate. The resulting extrudates were compared for degree of roast aroma generation by analysis of the pyrazine volatiles formed. In addition, the overall extent of the browning reaction was measured by monitoring brown color formation. Samples which contained ammonia exhibited a greater degree of brown color formation; however, ammonia adversely affected the total amount of pyrazines generated. The reactive nature of the free ammonia molecule was suspected to be the governing causative factor.