Impact of exogenous \u03b1-amylases on sugar formation in straight dough wheat bread

Gerold Felix Rebholz,Sebastian Dirndorfer,Katharina Anne Scherf,Thomas Hofmann,Corinna Dawid,Karin Sebald

doi:10.1007/s00217-020-03657-y

Abstract

The use of bacterial or fungal α-amylases is common in wheat bread production to improve several quality-related parameters such as loaf volume, crust color or staling behavior. To study the impact of exogenous α-amylases on straight dough wheat bread, we quantitated mono-, di- and oligosaccharides and residual α-amylase activity in bread crumb during storage for up to 96 h. Discovery-driven proteomics of the five α-amylase preparations studied showed that only a few different amylases per preparation were responsible for the hydrolytic effect. Compared to the control, the supplementation with α-amylase from Bacillus amyloliquefaciens in wheat dough preparation led to major changes in the sugar composition of bread crumb during storage with the formation of oligosaccharides like maltopentaose, maltohexaose, maltoheptaose, and maltooctaose. A residual activity corresponding to 4.0% of the applied activity was determined in the breads prepared with α-amylase from B. amyloliquefaciens, but no residual activity was detected for any of the other fungal or bacterial α-amylases from Aspergillus oryzae or Thermoactinomyces vulgaris. Whether the detected residual activity is related to the characteristics of bread staling or bread crumb properties must be clarified in further studies.

Highlights

Amylases are present endogenously in wheat flour, but their activities vary greatly depending on the type and variety of grain, the environmental conditions during cultivation, and the state of maturity at harvest [1]
It is generally accepted that the amount of amylases present endogenously in wheat flour is too low to have a technological impact during the manufacturing of wheat bread except in cases of pre-harvest
Five different α-amylase preparations commonly applied in bread production were analyzed regarding their protein composition and their impact on straight dough wheat breads

Summary

Introduction

Amylases are present endogenously in wheat flour, but their activities vary greatly depending on the type and variety of grain, the environmental conditions during cultivation, and the state of maturity at harvest [1]. The addition of α-amylase to wheat doughs improves the fermentation rate by providing additional substrates such as maltose and maltooligosaccharides to the yeast cells. This leads to a prolongation of the productive fermentation due to the fact that. The caramelization process, the Maillard reaction, and the Strecker degradation are reactions that take place during the baking process under the influence of heat and in the presence of various reducing sugars. They are mainly responsible for the flavor and taste of wheat bread [8]

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