Wheat flour must be high in both protein content and quality to develop the functional properties essential to bread baking. When mixed with water, flour forms a viscoelastic substance called gluten, which is composed of two protein fractions, glutenin and gliadin. The control of mixing time has also been associated with the glutenin fraction of the wheat flour. Differences between wheat varieties in bread-making properties appear to be a function of the nature of gluten. A study of Orth and Bushuk (1972) showed that loaf volume was inversely related to the amount of acid-soluble (in 0.05N acetic acid) glutenin and directly related to the proportion of insoluble glutenin (Fig.1). Glutenin was responsible for
loaf volume, which was confirmed by MacRitchie (1980, 1985). Glutenin was composed of high-molecular weight proteins with values reported from 150,000 to 3 million, while gliadins
were low-molecular weight proteins ranging in molecular weight from 25,000 to 100,000
daltons.