Protein based nanoparticles as matrices for encapsulation of lipophilic nutraceuticals

Abstract

Some globular proteins have the ability to bind lipophilic compounds onto their surfaces. A member of lipocalin proteins, beta-lactoglobulin, is the most recognized globular protein showing this behavior which could be linked with a possible biological role. Further examples of globular proteins showing ligand binding property are albumins such as, bovine and human serum albumins, alpha-lactalbumin, ovalbumin, etc. In general, the binding properties of lipophilic compounds are mediated by hydrophobic forces and it could involve particular domains of protein structure. In spite of, the exact ligand binding sites remains controversial for some globular proteins, there is no doubt this functional property arouses the interest in the development of innovative encapsulation systems for sensitive lipophilic nutraceuticals (LNs). In this sense, globular proteins could be used as carrier for LNs delivery being nontoxic, non-immunogenic, biocompatible and biodegradable materials. Moreover, considering that binding property depends on the non-polar nature of some protein surface regions, processes that promote the exposition of hydrophobic residues could be applied for increasing the LNs load in delivery systems. Controlled heat treatment could be a convenient strategy for increasing protein surface hydrophobicity and consequently improving their LNs binding properties. At the same time, the handling aqueous medium conditions (pH, ionic strength, presence of polysaccharides) as well as different processes leave to formation of protein based nanoparticles which could be incorporated in a lot of aqueous systems (foods, pharmaceuticals, cosmetics, etc.). In this chapter, a revision of literature about the use of protein based nanoparticles for LNs encapsulation is provided. Especial emphasis is made on the encapsulation of polyunsaturated fatty acids (PUFAs) as models of LNs. Some applications and biological implications of these encapsulation systems are also mentioned.