Microstructure and distribution of oil, protein, and starch in different compartments of canaryseed (Phalaris canariensis L.)

Abstract Background and objectives The aim of this study was to understand seed microstructure and oil, protein, and starch distribution in brown and yellow canaryseed that could provide an understanding of potential use of solvent‐free technologies for protein fractionation purposes. Findings Varying thickness of the bran was observed from the ventral to the dorsal side of the seed. The aleurone layer is mostly a single‐cell layer; however, it could occasionally be a double‐cell layer. The germ, endosperm, and aleurone layer contain oil. However, more oil is distributed in the endosperm area (3.88 g of oil in roller‐milled white flour) than in the germ and aleurone layer (2.83 g of oil in roller‐milled bran fraction). The endosperm also contains varying sizes of compound starch granules (~4–7 µm to 20 µm) and individual starch granules (~2–4 µm). Protein is widely distributed in the endosperm compared to the germ, aleurone layer, and bran. Conclusions Microstructural differences in different regions of the canaryseed were observed. The presence of higher oil content in the endosperm suggests that the application of solvent‐free technologies could be challenging for protein fractionation. Significance and novelty This study revealed microstructural and chemical differences in different regions of the seed. Especially, it showed the spatial distribution of oil, which is crucial in designing industrial processes, for “clean‐labeled” protein ingredients.