Abstract
The global demand for the milk protein concentrate (MPC) formulated consumer products and MPC as an ingredient has grown over the last decade. The U.S. still imports significant amounts of MPC, even after doubling its domestic MPC production over the past few years. Milk protein concentrates and isolates provide a variety of food ingredients, which gives excellent functionality and nutrition to different foods and beverages. However, caseinates and whey protein concentrates have good functionality especially solubility, as compared to the MPCs. The solubility of MPCs decreases with time. The objective of this thesis is to study the combined effect of the direct steam injection process and pH change on the functionality of MPCs.The functional and compositional characterization of MPC 70, 80 and NFDM, manufactured using combined effect of 7, 8, and 9 pH levels at 85 and 105°C direct steam injection (DSI) temperatures, has been reported in this thesis. High solubility samples of MPC 70, 80 and NFDM, were analyzed for solubility and microstructure after storage period of 20 days at 40°C. Proximate composition, protein compositional analyses, zeta-potential, hydrodynamic diameter (dh or derr), functionality (solubility, foaming, viscosity, heat stability, and rennet gelation), and microstructure analyses were performed to understand the effect of treatment on powders. Our hypothesis was that pH and temperature changed configuration of casein and whey proteins, respectively, and resulted in different functionality of MPCs. We have observed an increase in the means of solubility, zeta potential, ash, viscosity, and a decrease in hydrodynamic diameter of MPC70 and 80 samples with increased pH at both evaluated temperatures. By using scanning electron microscopy, a decrease in aggregation was observed with an increase in pH at both temperatures in M70 and M80 samples. Opposite effect was seen in NFDM samples. No significant effect was observed in protein compositional, foaming, fat, protein, and moisture analysis in NFDM, MPC70, and 80 samples.