The objective of the study reported in this research paper was to produce micellar casein concentrate (MCC) and milk protein concentrate (MPC) with 80% crude protein relative to total solids (TS) using MF and UF processes respectively. Additionally, capillary gel electrophoresis (CGE) was used to study the protein fractions in retentate and permeate. For MCC production, 227 L of pasteurized SM was subjected to MF using 0.5-micron spiral wound polyvinylidene fluoride membrane. During the process, diafiltration (DF) water was added at six intervals, totaling 100% of the feed volume. For MPC production, 227 L of pasteurized SM from the same lot was subjected to UF using 10 kDa Polyethersulfone membranes. During the process, DF water was added at four different intervals, with a final total addition of 40% of the feed volume. Both processes used a volume reduction of five. There were significant (p < 0.05) differences in all of the compositional parameters, except fat and casein for the MF retentate (MFR) and UF retentate (UFR). UFR had a higher crude protein (CP), TS, lactose, ash and calcium content as compared to MFR and this affected the CP/TS ratio found in both the retentates. The differences in membrane pore sizes, operating pressures and level of DF used all contributed to the differences in final CP/TS ratio obtained. The CGE analysis of individual protein fractions present in the UFR and MFR showed that UFR has a β-lactaglobulin to α-lactalbumin (α-LA) ratio similar to SM, whereas the MFR has a higher ratio, indicating preferential transmission for α-LA by the MF membrane. The results from this study show that MF and UF processes could be used for production of MCC and MPC with similar CP/TS ratio with careful selection of operating parameters, and that CGE can be used for detailed analysis of various protein fractions.

The physicochemical changes during the storage of high protein powders, such as skim milk powder (SMP), nonfat dry milk (NDM), and milk protein concentrates (MPC), can result in a variation in the functional properties of the powders. The objective of this study was to evaluate the effects of the storage of various milk powders (SMP, NDM, MPC40, and MPC70) on their functional properties. Three different lots of the powders were collected from US manufacturers and were analyzed for functional properties after 3, 9, and 15 months of storage at 25 °C. Additionally, this study also evaluated the effects of seasonal variation on the functionality of SMP and NDM. Functional properties, such as solubility, emulsification ability index (EAI), foaming, and surface hydrophobicity index (SHI), were evaluated at each storage time point. The solubility of MPC70 and the foam overrun of SMP, MPC40, and MPC70 decreased significantly (p < 0.05) with an increase in the storage time. The emulsification properties of MPC70 were significantly higher than other powders. Except for foam drainage, there was no effect of the season on the SMP and NDM functional properties. The storage of milk powders has an impact on some functional properties, and a proper selection of powders based on end-use is recommended.

Dairy proteins are potential and multipurpose ingredients used to prepare various food products. It exhibits many beneficial functionalities and bioactivities in the processing of food products. All the functionalities of different dairy proteins depend on their peculiar structural characteristics. So, the present study aimed to characterize high-protein powders with different matrices (milk protein concentrate (MPC), rennet casein (RCN), micellar casein concentrate (MCC), whey protein isolate (WPI), and native whey concentrate (NWC)) for their composition, handling, and reconstitution properties, and microstructure and compared them with whole milk powder (WMP) and skim milk powder (SMP). The bulk density of the high-protein powders was significantly (p < 0.05) lower than WMP and NFDM. Due to the low bulk density of the high-protein powders, the wettability of these powders in the water was very high. Microstructural analysis of powders by scanning electron microscopy reveals that the high-protein powder had tetrahedron-to-polyhedron-shaped particles depending on the protein level. The idea regarding the powder’s morphology might be helpful for further improvement in the production processes to modify the functional properties of high-protein milk powders.

In dairy-based imitation mozzarella cheese (IMC) formulations, intact casein is critical and imparts IMC with a firm and elastic, stringy, melted texture. Rennet casein (RCN) is the desired ingredient to provide intact casein in IMC and is preferred over milk protein concentrate (MPC) and micellar casein concentrate (MCC). Transglutaminase (TGase), a crosslinking enzyme, alters the physical properties of MPC or MCC and may change IMC functionality. The objective of this study was to determine the effect of TGase-crosslinked MPC and MCC powders on the functionality of IMCs. The TGase treatment included TGase at 0.3 (L) and 3.0 (H) units/g of protein and a control (C) with no TGase addition. Each IMC formulation was balanced for constituents and was produced in a Rapid Visco Analyzer (RVA). The MCC or MPC powder with high TGase enzyme in IMC formulation did not form an emulsion. The IMC containing TGase-treated powders had a significantly (p ≤ 0.05) higher RVA-viscosity during manufacture and transition temperature (TT), and a significantly (p ≤ 0.05) lower Schreiber melt test area. The IMC made from MPC (with or without TGase) had lower TT values and Schreiber melt test area as compared with that made from MCC. The TGase-treated MPC and MCC, when used for IMC manufacture, were comparable to IMC manufactured with RCN in texture and some measured melted characteristics. In conclusion, TGase treatment alters the melt characteristics of MCC and MPC in IMC applications.

Both hydrodynamic cavitation (HC) and temperature elevation are important pretreatments for improving the performance of liquid food processing by reducing viscosity. In this study, we assessed the impact of HC and elevated temperature on the functionality of milk protein concentrate powder with 80% protein (MPC80) prepared from nanofiltration (NF) of ultrafiltration (UF) retentate. Skim milk was concentrated using UF, and the retentate was further subjected to HC and concentrated using NF, then spray dried to obtain MPC80 powder. The functionality of these powders processed using NF at 22 °C, NF at 50 °C, HC and NF at 22 °C, and HC and NF at 50 °C were evaluated. Rennet coagulation time of reconstituted MPC80 from different NF treatments was like skim milk when treated with 0.1% CaCl₂. High-temperature NF reduced the water solubility of MPC80 powder (70.03 to 79.20%) at room temperature, but it was similar when measured at 50 °C (86.05 to 92.91%). The HC improved foaming (92.22 to 112.89%) but did not impact the emulsifying capacity (59.58 to 61.38%) and heat stability (18.04 to 20.22 min). Results showed that the HC and high-temperature NF utilized to increase the production efficiency of MPC80 also maintained the functionality of the powders after spray drying.