We investigated the effects of different concentrations of whey protein isolate (WPI) on oat starch characteristics in terms of pasting, thermal, and structural properties. The pasting properties of the starch showed that hot paste viscosity increased with the addition of WPI in the system, and relative breakdown decreased. Thermal analysis showed a significant effect of WPI on oat starch by increasing the peak temperature of differential scanning calorimeter endotherms. The X-ray diffraction and Fourier transform infrared spectroscopy studies revealed that WPI increased the ordered structuration of starch paste, as evident by an increase in relative crystallinity; in addition, a decrease in infrared bands at 1,024 cm-1 and 1,080 cm-1 suggested decreased gelatinization of oat starch granules. Overall, WPI at different concentrations affected the oat starch gelatinization properties.
Evidence for the asymmetric distribution of phospholipids in the milk fat globule membrane (MFGM) was obtained by applying 3 washing processes using aqueous solutions with different degrees of stringency (mild, intermediate, and intensive) to milk fat globule (MFG) surfaces in simulated milk ultrafiltrate buffer. We detected no change in the amount of cholesterol after the mild washing process; however, intensive washing yielded a relative enrichment of surface cholesterol with concomitant damage to the outer bilayer of the MFGM. This finding supports the hypothesis of repartitioning of cholesterol on MFG surfaces during mechanical treatments. An updated model system of lipid organization was developed according to the results of relative depletion of individual phospholipids, as analyzed by HPLC.