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Rye Bread Defects: Analysis of Composition and Further Influence Factors as Determinants of Dry-Baking

Oest, Marie; Bindrich, Ute; Voß, Alexander; Kaiser, Heinz; Rohn, Sascha

FG Lebensmittelchemie und Analytik

For decades, the evaluation of rye milling products have been aimed at detecting raw material defects that are linked to excessive enzyme activity. Those defects were indirectly characterized by the rheological methods of the dough or the final products. However, such methods do not sufficiently reflect the baking properties of all rye flours present on the market. A further problem is the continuing climate change, which affects compound composition in rye. So far, these bread defects can only be corrected by process engineering (e.g., extended dough resting). Therefore, it is necessary to characterize the main determinants of the quality defects prior to the baking process in order to predict baking quality and not waste raw material, energy, and time. In this study, it was found that the water accessibility of starch for gelatinization and its partial inhibition by certain components play a major role in baking quality. Specifically, high amounts of insoluble nonstarch-polysaccharides (NSPSs) and a hindered denaturation of proteins seem to be an indication and reason for poor baking quality. However, traditional quantitative analysis of the ingredients and properties of the rye milling products (e.g., falling number, protein content, amylographic data) does not allow any reliable conclusions about rye flour suitability for use as bread rye. It can be concluded that more complex compositional aspects (e.g., complexation of compounds) need to be characterized for future quality control of rye.