These findings cast light on the importance of colloidal particle's surface properties and pH on their connectivity with the surrounding matrix, which modulates the bulk microstructure and rheological properties with potential functional consequences, such as milk lipid digestion.Īdhesion force Atomic force microscopy Casein micelle Emulsion Interfacial properties Lipid droplet.Ĭopyright © 2019 Elsevier B.V. Consequently, casein-coated homogenized fat globules yield stiffer milk acid gels. The adhesion between individual fat globules and casein micelles was higher upon homogenization, especially at acid pH where the work of adhesion increased from 3.3 x 10 -18 to 14 x 10 -18 J for native and homogenized fat globules, respectively. Fresh coconut milk contains nearly 55 ± 3 aqueous, 37 ± 2 fat and 8 ± 2 protein 3. caseins) and pH govern their interactions with casein micelles. Coconut milk is an oil-in-water emulsion, stabilized by the naturally occurring proteins (albumins and globulins) and phospholipids (lecithin and cephalin) 1, which requires extra energy to destabilize this emulsion 2. It was found that an increase in energy density can reduce the particle size, increase the amount of adsorbed protein and improve the stability of the emulsion ( Silva, Zisu, & Chandrapala, 2019 ). We showed that the surface properties of milk fat globules (biological membrane vs. The composition of milk proteins and the energy densities influenced the physicochemical properties of grape seed oil emulsions. In this study, macroscale rheometry, microscopic observations, nanoscale AFM-based force spectroscopy and physico-chemical analysis were combined to examine the interfacial composition and structure of milk fat globules and to evaluate their interactions with casein micelles. An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation.Emulsions are part of a more general class of two-phase systems of matter called colloids. The absolute quantification of PLs was analyzed using 31P NMR spectroscopy. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification. We compared phospholipids (PLs), PL fatty acid (FA) composition, and milk fat globule size and structure in human milk (n 120) from mothers of full-term and preterm infants during lactation (colostrum, transition, 1 mo, 2 mo, and 3 mo) and 8 brands of infant formulas. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins.
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