PROTEIN-LIPID AND PROTEIN-CARBOHYDRATE INTERACTIONS IN THE GLUTEN COMPLEX

Abstract

It is well known on the basis of earlier research and observations that defatting of flour or addition of polar lipids affect gluten proteins. More recent research made in Kansas, Winnipeg and also in our laboratory revealed the important role of phospho-and glycolipids in the interactions of proteins and lipids and in the formation of protein lipid aggregates. It was also stated that the formation of aggregates mentioned above is not a spontaneous effect but a result of specific interactions between lipids and given protein subunits. Good correlation was found between the polar lipid content and baking value of wheats resp. flours. The role of carbohydrates in the formation of gluten complex has not been investigated so thoroughly as the lipid-protein interaction. Theoretically - due to the polar character of carbohydrates - hydrogen bonds may be formed between polar side chain groups of amino acid residues and hydroxyl groups of carbohydrates. A covalent binding of carbohydrates by O or N -glycosidic bond is also possible. Ionic binding may not be excluded if oxidized carbohydrate derivatives are present. In our laboratory Örsi has found that some high molecular weight components of glutenin contain a significant quantity of carbohydrates. Experiments made in our laboratory showed that some gel-forming polysaccharides containing ionic groups improve the dough properties and stability. The explanation of the character of interactions needs further investigations.