Cereal Chem 69:169-173   |  VIEW ARTICLE

Wheat Hardness. II. Effect of Starch Granule Protein on Endosperm Tensile Strength.

R. B. Malouf, W. D. A. Lin, and R. C. Hoseney. Copyright 1992 by the American Association of Cereal Chemists, Inc. 

A hard and a soft wheat flour were fractionated into starch, gluten, and water solubles. These fractions were interchanged and reconstituted into doughs, which were dried and ground. Tablets made from these reconstituted flours had low tensile strength when the starch fraction was from the soft wheat, regardless of the source of the other two fractions. Tablets had intermediate tensile strength when made with soft wheat gluten and the hard wheat starch fraction. Proteins, including the 15-kDa sodium dodecyl sulfate- polyacrylamide gel electrophoresis band, were removed from the soft wheat starch fraction by using either pronase or sodium dodecyl sulfate. These treatments did not gelantinize the starch. The starch fraction from soft wheat with the surface protein removed gave tablets with high tensile strength. These results support the hypothesis that the 15-kDa protein associated with soft wheat starch granules has a dominant influence on wheat endosperm texture. Pronase treatment removed essentially all protein from the starch fractions, suggesting that nearly all proteins associated with starch granules are on the surface.