Effect of pH and cosolvent sucralose on the solvation profile of ovalbumin: Ultrasonic and molecular simulation studies

The protein-sucralose (SL) interaction is getting more attention in food and pharmaceutical products due to the peculiar properties of SL compared to the normal sugars. This article discusses the effect of SL as an additive combined with pH variation on the solvation profile of Ovalbumin (OVA) by molecular interaction studies. The findings were explored experimentally by measuring density, ultrasound velocity, viscosity, surface tension and further extended from the analysis of some thermo-acoustical parameters. Results suggested that cosolvent SL interact with OVA in larger magnitude in acidic pH region whereas lesser in alkaline pH region. In addition, results confirm the presence of dipole-dipole interactions exists in both pH regions but differ in their magnitude. The simulation results suggest that the solvent (water)/cosolvent (SL) accumulation on the OVA surface has a pH-dependence behavior. The MD coupled to minimum distance distribution function gmd(r) showed an accumulation of SL closer to the OVA surface at ∼1.8 Å and water at ∼2.5 Å, suggesting that SL structure plays a vital role in the weakening of the preferential exclusion of itself from the OVA surface. The prominent existence of non-covalent interactions especially hydrogen bonding and van der Waals interactions are confirmed by both experimental and computational studies thereby leads to OVA denaturation in both acidic and alkaline regions to a different extent.