Practical aspects of the dynamic light scattering method applicability for evaluation the solubility of whey protein hydrolysate

Sustainable development of the dairy industry provides for resource saving, reduction of enterprises emissions into the environment as well as preservation of components of raw materials during the processing technological cycle. The presence of a wide range of functional ingredients in the whey composition makes it possible to recommend it as a raw material source in the production of various assortment groups of food products. A promising trend of whey processing is fractionation and drying to obtain products with a long shelf life, high nutritional and biological value. The aim of the work was to study the completeness and kinetics of dissolution of whey protein hydrolysate. The objects of research were the cheese whey obtained during the production of Russian cheese at PJSC DC “Voronezhsky”; its ultrafiltration concentrate (UF-concentrate), developed with a protein concentration factor of 3.7-3.9; whey protein hydrolysate produced using enzyme preparations Promod 439L and Flavorpro 766MDP. The resulting hydrolysate was dried on a spray dryer VRD-5. Based on the analysis of the whey protein nitrogen index the necessary modes of pasteurization of cheese whey and whey protein hydrolysate were determined: t = (80 ± 2)°C, τ = 15 sec during subsequent proteolysis in the UF-concentrate; t = (76 ± 2)°C, τ = 15 sec before direct drying of whey protein hydrolysate. The ability to recombination the dry product was assessed by its particle-size distribution (the main particle size was 56.13 μm s for a sample of whey protein hydrolysate and 190.5 μm for a UF-concentrate). It was found that the whey protein hydrolysate was subjected to more complete rehydration and at a higher rate in comparison with the UF-concentrate of cheese whey. This is due to a change in the charge of proteins and peptides during proteolysis, which increased the solubility of nitrogen-containing components, as well as reduced the amount of air sorbed by proteins and required less time for the destruction of such agglomerates during recombination.