Biomimetic membrane was investigated as model systems to mimic the structure of milk fat globule membrane (MFGM) and to study the effects of thermal processing-induced changes in MFGM fractions on membrane morphology and physical properties. Molecular docking was utilized to screen xanthine oxidase (XO) as the MFGM protein most likely to bind to phospholipid molecules on MFGM. Fluorescence spectroscopy verified that XO formed stable complexes with DOPE, DPPC, and PS 18:0-18:1, with the strongest binding to DOPE. Two types of artificial fat globule membrane (AFGM) were further constructed using XO with phospholipid molecules, including N-AFGM (simulating MFGM in raw milk) and P-AFGM (mimicking MFGM in ultra-pasteurized milk). The results of atomic force microscopy showed that the P-AFGM had significantly less liquid ordered phase (Lo), more aggregation of XO, smoother surface, higher Young's modulus, and more prone to rupture compared to N-AFGM. These results contribute to a better understanding of the relationship between changes of MFGM composition induced by thermal processing and fat globule stability.
Keywords: Biomimetic membrane; Liquid ordered phase; Milk fat globule membrane; Nano-mechanical properties; Young’s modulus.
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