The self-association properties of partially dephosphorylated bovine beta-casein
2023
Song, Sijia | Lin, Yingying | Zhang, Yuning | Luo, Yujia | Guo, Huiyuan
Partially dephosphorylated bovine beta-casein has great potential to become a novel infant formula base in the future. At present, there are few studies on the self-association properties of partially dephosphorylated bovine beta-casein, which are very essential and important for its processing and application. This study investigated the self-association properties and physical stability of partially dephosphorylated bovine beta-casein. Partially dephosphorylated bovine beta-casein was prepared using phosphatase and the dephosphorylated isoforms were precisely identified through UPLC-ESI-MS. Afterwards, the self-association properties of partially dephosphorylated bovine beta-casein at different protein concentrations, temperatures, CaCl₂ concentrations and pH were studied. Partially dephosphorylated bovine beta-casein was more sensitive to increases in protein concentration (0.03%–0.25%), temperature (4–54 °C), CaCl₂ concentration (0–9 mM) and pH (4–8) and prone to form large protein aggregates compared with native beta-casein (>1 μm vs < 100 nm). However, the protein aggregation results at pH 4 were exceptional, with partially dephosphorylated beta-casein forming smaller aggregates than native beta-casein (<30 nm vs > 300 nm). The physical stability of native and partially dephosphorylated beta-casein solutions was also determined and the results were in agreement with above-mentioned results of protein aggregation. The decrease in negative charge caused by the loss of phosphate groups seemed to be responsible for the difference in self-association properties between native and partially dephosphorylated beta-casein. These findings will provide effective guidance for infant formula manufacturers.
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