Formation and colloidal stability of ovalbumin-retinol nanocomplexes

Abstract

This work is aimed to obtain and characterize nanocomplexes formed by non-covalent attractive interactions between ovalbumin (OVA) and retinol (RET). In order to gain some ideas about the effect of OVA aggregation on RET complexation, OVA nanoparticles (OVAn) obtained by controlled heat treatment (85 °C, 5 min) were also evaluated. Nanocomplex formation was monitored by intrinsic and extrinsic fluorescence spectroscopy. Results suggest that OVA was more effective for binding RET than OVAn, possibly because aggregate formation could employ some hydrophobic patches needed for RET binding. Furthermore, nanocomplex colloidal stability was studied by means of absorbance (at 400 nm), particle size distribution (PSD) and ζ potential determinations. At pH values of common foods (4.0 and 7.0), nanocomplex colloidal stability mainly depended on aqueous phase behaviour of the proteins (OVA and OVAn). Finally, long-term photochemical stability against light and oxygen of RET nanocomplexes depended on solution pH and protein aggregation.