Biochemical characteristics of soft wheat grain associated with endosperm separation from bran and flour yield

Authors: Ji, Taehyun; MA, FENGYUN - The Ohio State University; Baik, Byung-Kee

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2020
Publication Date: 5/5/2020
Citation: Ji, T., Ma, F., Baik, B.V. 2020. Biochemical characteristics of soft wheat grain associated with endosperm separation from bran and flour yield. Cereal Chemistry. 97(3):566-572. https://doi.org/10.1002/cche.10271.
DOI: https://doi.org/10.1002/cche.10271

Interpretive Summary: Flour yield, expressed as the weight percentage of flour obtained from roller milling over wheat grain, is directly related to the profit of millers, and is therefore considered to be one of the most important quality traits. Efficient and clean detachment of endosperm from bran during milling has been identified as a prerequisite for high flour yield and shows a closer relationship with flour yield than other grain characteristics. Wheat grain with a high flour yield has less endosperm remaining attached to bran than wheat grain with a low flour yield. However, little is known about the endosperm characteristics that affect its detachment from bran during milling, which makes it difficult to screen wheat grain for high flour yield potential. By extracting the endosperm remaining attached to bran and determining the composition for ten wheat varieties possessing a wide range of flour yield potentials, we observed a large variation in the composition of the endosperm extracted from bran among the wheat varieties. Moreover, the varieties with high flour yield potential were relatively lower in water-soluble arabinoxylan content than those with low flour yield potential in the endosperm extracted from bran. As the main constituent of the endosperm cell wall, arabinoxylan is expected to play a key role in endosperm cell separation and detachment from bran during milling. Wheat varieties with high flour yield potential also showed a relatively lower water-soluble arabinoxylan content of flour. Both water-soluble arabinoxylan contents of flour from milling and of endosperm extracted from bran showed negative relationships with flour yield. This suggests that a low water-soluble arabinoxylan content of the outer endosperm of wheat grain is desirable for the easy detachment of endosperm from bran during milling, contributing to increased flour yield. The association of low water-soluble arabinoxylan with a better detachment of the outer endosperm from bran during milling (and consequently higher flour yield) provides wheat breeders with an efficient tool to screen for breeding lines possessing high flour yield potential in the development of wheat varieties.

Technical Abstract: Background and objectives: Endosperm separation from bran during wheat grain milling has a substantial influence on flour yield, whereas little is known about the endosperm characteristics affecting its detachment from bran. The associations of the outer endosperm characteristics with its separation from bran during milling, and subsequently with flour yield, were determined. Findings: The yields of flour and remnant endosperm of bran (REB) for ten soft red winter wheat varieties ranged from 66.7 to 75.9% and 1.7 to 3.7%, respectively. The ash, water-soluble AX and ß-glucan contents of the REB exhibited significant relationships with flour yield at P < 0.05. Wheat varieties of >75% flour yield exhibited higher ash and lower water-soluble AX contents of the REB than the varieties of <68% flour yield. The ash and water-soluble AX contents of flour also exhibited significant relationships with flour yield at P < 0.01. Conclusions: The water-soluble AX content of endosperm is implicated in the separation of endosperm from bran during milling of wheat grain. Significance and novelty: Wheat grain outer endosperm that is low in water-soluble AX could positively contribute to flour yield because of its role in the efficient detachment of endosperm from bran during milling.