Formation of maillard reaction products involving whey proteins and lactose

Maillard-type reactions can occur when proteins are heated in the presence of reducing sugars, and result in glycation of the N-terminal amino acids and lysine residues. These reactions proceed through a number of pathways, resulting in a diverse range of reaction products. Interest in the study of such reactions has recently been stimulated by the observation of whey protein-lactose adducts in wheys prepared from fresh milk after laboratory separation of cream (40 degrees C) and casein (pH 4.6) (Burr et al. 1996). Maillard-type reactions involving whey proteins are of commercial interest as they are promoted by a number of industrial processes encountered in whey processing (Leonil et al. 1997), and the reaction products may have new and useful characteristics. Structural modifications resulting from the glycation of beta-lactoglobulin at pH 7.2, and their effects on solution conformation and related physicochemical properties have recently been reported (Morgan et al. 1999). We describe here the formation of advanced Maillard reaction products (fluorescent) in beta-lactoglobulin-enriched whey protein-lactose model systems over a wide pH range.