6. Conclusions and Future Trends.
As globular proteins whey proteins undergo several conformational changes and interactions during thermal treatments of milk products and in model systems. Glycation of whey protein during heat treatments has received special attention due to its effect on the technological and nutritional properties of milk and whey protein products. The extent of these changes depends on the severity of the heat treatments, heating conditions, medium and type and ratio of the carbohydrate present. In the presence of lactose as the main sugar present in milk products, lactosylation of the main whey proteins results in variable losses in lysine, decreases in their antigenicity and digestibility. Generally, the solubility and thermal stability of β-Lg and α-La can be improved by glycation because the pI of the protein is shifted to lower pH values and to the decrease in the formation of aggregates. Also, glycated β-Lg and α-La exhibit better emulsion stability, foam stability and high antioxidant activity than the native proteins.
Based on studies on individual whey proteins, attempts have been made to expand the applications of whey protein products particularly WPI via modification with Maillard reaction. The use of polysaccharides particularly dextrans and maltodextrins for glycation and limiting glycation to the early stage of Maillard reaction aimed to produce conjugates modified with functional properties and least losses in the sensory and nutritional properties of the native proteins. Encouraging results have been obtained from several studies done along this line but more studies are needed to optimize the reaction conditions.
