Self-assembled nanoparticles from heat treated ovalbumin as nanocarriers for polyunsaturated fatty acids

Abstract

The objective of the present work was to obtain and characterize two heat induced (85 °C, 5 min) ovalbumin nanoparticles (OVAn1 formed at pH 11.35 and OVAn2 formed at pH 7.50). In addition, the impact of these OVA nanosized aggregates on the formation and characterization of inclusion nanocomplexes formed with two polyunsaturated fatty acids (PUFAs): linoleic acid (LA) and its isomer, conjugated linoleic acid (CLA) was studied. The pH in which heat treatment was performed had a great impact on nanoparticles hydrodynamic diameter (dH). Nanoparticles dH values were 24.63 ± 0.04 nm for OVAn1 and 92.0 ± 0.2 nm for OVAn2, respectively, and no significant differences in ζ potential values (p > 0.05) were detected. Nanocomplexes colloidal characteristics were studied by particle size distribution (PSD) and ζ potential determinations. In all cases, size measurements showed that PUFAs binding promoted an increased nanoparticles size. In addition, atomic force microscopy (AFM) examination for nanoparticles and nanocomplexes showed a rounded shape and an increase in dimensions of the nanocomplexes which was attributed to LA and CLA binding. On the other hand, nanocomplex formation was monitored by intrinsic and extrinsic fluorescence spectroscopy. Results highlighted that both nanoparticles bound LA and CLA in greater amount than OVA did. Besides, both nanoparticles were able to bind more amount of LA than CLA. Results suggested that knowledge of differences in OVA nanoparticles properties and PUFAs molecular structure is a relevant requisite for the design of inclusion nanocomplexes with especial colloidal properties.