Effect of heat treatments on the incorporation of milk serum proteins into the fat globule membrane of homogenized milk

Abstract

Summary The incorporation of serum proteins into the synthetic fat globule membrane in milks that had been heated and subsequently homogenized has been quantitatively determined using electrophoresis and densitometry. The results indicated that the amounts of serum proteins present in the fat globule membrane were smaller in milk that was heated before homogenization than in milk that had been homogenized and then heated. The thickness of the adsorbed layer of protein on the surfaces of the fat particles, measured using photon correlation spectroscopy in dissociating and non-dissociating buffer solutions, was also lower in the former case (∼ 20 nm) compared with the latter (∼ 34 nm). The kinetics of adsorption of both β –lactoglobulin and α-lactalbumin in heated homogenized milk on the vacant ‘sites’ on the synthetic fat globule membrane followed similar trends at 75 and 90 °C.