Impact of exogenous maltogenic α-amylase and maltotetraogenic amylase on sugar release in wheat bread

The use of exogenous maltogenic α-amylases or maltotetraogenic amylases of bacterial origin is common in wheat bread production, mainly as antistaling agents to retard crumb firming. To study the impact of maltogenic α-amylase and maltotetraogenic amylase on straight dough wheat bread, we performed a discovery-driven proteomics approach with commercial enzyme preparations and identified the maltotetraogenic amylase P22963 from Pelomonas saccharophila and the maltogenic α-amylase P19531 from Geobacillus stearothermophilus, respectively, as being responsible for the amylolytic activity. Quantitation of mono-, di- and oligosaccharides and residual amylase activity in bread crumb during storage for up to 96 h clarified the different effects of residual amylase activity on the sugar composition. Compared to the control, the application of maltogenic α-amylase led to an increased content of maltose and especially higher maltooligosaccharides during storage. Residual amylase activity was detectable in the breads containing maltogenic α-amylase, whereas maltotetraogenic amylase only had a very low residual activity. Despite the residual amylase activities and changes in sugar composition detected in bread crumb, our results do not allow a definite evaluation of a potential technological function in the final product. Rather, our study contributes to a fundamental understanding of the relation between the specific amylases applied, their residual activity and the resulting changes in the saccharide composition of wheat bread during storage.