WATER-SOLUBLE DEXTRINS FROM ALPHA-AMYLASE-TREATED BREAD AND THEIR RELATIONSHIP TO BREAD FIRMING

White bread was supplemented with malted barley flour, four bacterial, and two fungal sources of a-amylase to ascertain their effect on brea d firming. The malt-supplemented bread firmed at a faster rate than th e standard, unsupplemented bread. The fungal amylases and one of the b acterial amylases reduced the rate of bread firming compared to that o f the standard. The remaining three bacterial amylases reduced the rat e of bread crumb significantly more than did the other treatments. Hig h-performance anion-exchange chromatography was used to analyze the wa ter-soluble dextrins extracted from the aged, supplemented, and unsupp lemented bread crumb. Certain peak areas obtained from the chromatogra ms were shown to be highly correlated with a reduced rate of bread cru mb firming. Other peaks were highly correlated with an increased rate of bread crumb firming. When comparing only the bacterial enzymes, the three bacterial alpha-amylases that produced the lowest rate of bread crumb firming produced peaks that were significantly and highly corre lated to a reduced rate of bread crumb firming. The fourth bacterial a mylase supplemented bread, which firmed at the same rate as the two fu ngal amylase supplemented breads, contained more carbohydrate in those peaks and significantly and positively correlated to an increased rat e of bread crumb firming.