Cereal Chem 72:70-75  |  VIEW ARTICLE

Wheat Flour and Defatted Milk Fractions Characterized by Differential Scanning Calorimetry. I. DSC of Flour and Milk Fractions.

N. Erdogdu, Z. Czuchajowska, and Y. Pomeranz. Copyright 1995 by the American Association of Cereal Chemists, Inc. 

Differential scanning calorimetry (DSC) thermograms were determined for wheat flour and milk fractions. Compositional and structural differences between prime and tailings starch apparently affected their DSC thermograms and interaction patterns. Tailings starch had a lower gelatinization enthalpy and a higher amylose- lipid complex transition enthalpy than did prime starch. These observations were attributed to the faster rate of heat transfer and higher accessibility to water, presumably related to the smaller granule size of tailings starch. Gluten lowered the temperatures of the amylose-lipid complex endotherm of both prime and tailings starches. Water solubles increased the gelatinization temperatures of the starches due to the competition for available water. Laboratory-prepared acid whey showed higher denaturation temperatures than sweet whey, which is explained by the acid- resistant character of the major whey protein beta-lg. A commercial whey protein concentrate showed endotherm temperatures that were considerably higher (greater than 40 C) than those of whey powders. Ultrafiltration in commercial processing could be responsible for this temperature shift. The degree to which protein is concentrated by ultrafiltration or dialysis affects the relative concentration of water solubles and influences the functional properties and interactions of whey protein concentrates with wheat flour components.