No abstract

Background and objectives:In the wheat endosperm, the storage proteins glutenin and gliadin form a proteinaceous matrix deposited among starch granules and when hydrated, interact to form gluten. Although the genetics, rheology, and molecular characterization of these proteins have been widely studied, there remains a lack of knowledge in the structural characterization of how they form gluten. The objective of this study was to evaluate methods of wheat kernel preparation for electron microscopy and assess how they affect the proteinaceous matrix. Findings: Two methods were evaluated; microwave and refrigeration treatment of chemically fixed and sectioned wheat kernels. Of the two treatments, the microwave treatment induced the formation of gluten fibrils in the kernel endosperm. In some of the refrigeration-treated kernels, protein sheets were observed. Additional protein filaments were seen directly interacting with B-type starch granules. Conclusions: Microwave treatment for preparing wheat kernels for electron microscopy induces a change in the kinetics stabilizing the gluten proteins in the wheat endosperm to form gluten fibrils. Significance and novelty: To date, microscopic studies of gluten formation have evaluated flour or doughs, whereas this study evaluated gluten formation in the intact wheat endosperm. These findings can help direct future studies regarding gluten formation and artifacts in fixed wheat kernels.