We investigated the influence of three types of monoglycerides, glyceryl monostearate (monostearate), glyceryl monooleate (monooleate) and glyceryl monoelaidate (monoelaidate), on protein during dough preparation. The addition of monooleate and monoelaidate decreased the amount of protein in the ethanol soluble fraction (corresponding to gliadin) and increased the water soluble fraction. Monostearate did not produce these changes in the protein fractions. The quantities of monooleate and monoelaidate in the ethanol soluble fractions were larger than that of the monostearate. The surface hydrophobicity of the water soluble protein and the 0.01 N acetic acid soluble protein in the dough was determined using the magnesium of 1-anilino-8-naphthalenesulfonic acid. The doughs containing monooleate or monoelaidate showed a decrease in the hydrophobicity of the proteins. After the defatting operation with butanol to remove the monoglycerides, the surface hydrophobicity of these defatted proteins nearly increased to the level of protein which contained no added monoglyceride. It was indicated that the unsaturated monoglycerides, monooleate and monoelaidate were adsorbed into the protein during the dough mixing and lowered the surface hydrophobicity. It was considered that the presence of a double-bond component in the fatty acid may cause bonding to the dough protein.

The effect of the addition of alpha-lactalbumin and beta-lactoglobulin fractionated from whey protein isolate (WPI) on the texturization of rennet casein was investigated. Each whey protein component was added to rennet casein at a level of 5% on a dry basis. Surface hydrophobicity of each textured casein product was determined by using 1-anilino-8-naphthalene-sulfonate (ANS) and hydrophobic gel chromatography. An addition of beta-lactoglobulin was found to be effective on decreasing the hydrophobicity of the resultant textured product, whereas alpha-lactalbumin was not. A decrease of the hydrophobicity, which was shown when beta-lactoglobulin was added, was possibly associated with the formation of beta-lactoglobulin-casein complex during cooking. The fibrousness of the product blended with beta-lactoglobulin was superior to that containing alpha-lactalbumin. It was indicated that beta-lactoglobulin contained in WPI played a major role in improving the fibrousness of the resultant textured product.