Utilization of low-temperature heating method to improve skim milk production: Microstructure, stability, and constituents of milk fat globule membrane

In the process of defatting milk, preheating treatment is an important factor affecting the flavor of skim milk. Here, raw milk was preheated at different times and temperatures. Then laser confocal microscopy, multiple-light scattering instrument, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to analyze the microstructure of milk fat globule membrane (MFGM), milk stability, and MFGM protein (MFGMP) components. Results showed that phospholipid domain of MFGM changed from an ordered state (Lo) to a disordered state (Ld) with increase in treatment temperature and time, leading to an increase in MFGMP content in skim milk. During the stability test, the stability of raw milk decreased significantly with increase in preheating temperature, while the opposite was true for skim milk. Finally, the results of MFGMP differentiation analysis showed that, the content of ten taste-related MFGMPs in the control group samples was significantly lower compared to the optimal group (P < 0.05).