Effect of high pressure on ovalbumin - Polysaccharide interactions

Probe spectrofluorimetry studies for ovalbumin (OVA) show an increase in su rface hydrophobicity at pressures > 400 MPa. Pressure treatment of mixtures of OVA+ dextran sulphate (DS) greatly reduces the surface hydrophobicity. Size exclusion chromatography data indicate that stronger protein-polysacch aride complex(es) are formed during treatment at low ionic strength and pH 6.5. Emulsions made with pressurized (600 MPa) OVA in the presence of polys accharide at pH 6.2 and low ionic strength exhibit the improved emulsifying efficiency and stabilizing properties of the protein. Under pressure treat ment at pH less than or equal to 6.5, OVA forms reversible electrostatic co mplex(es) and the strength of interaction is related to the charge density on the polysaccharide (DS > iota -carrageenan (iota -CAR) > kappa -carragee nan (kappa -CAR)). Complexation of OVA with polysaccharide seems to protect the protein against loss of functionality from pressure-induced aggregatio n.