Coacervates of whey proteins to protect and improve the oral delivery of a bioactive molecule

The potentiality of heteroprotein complex coacervates as biocarrier for a bioactive was investigated. Vitamin B9 (B9), also known as folic acid, was encapsulated by complex coacervation of two whey proteins (WP), β-lactoglobulin and lactoferrin. The stability and bioavailability of formed B9-WP coacervates was then characterized. Under degradative conditions in vitro (UV light irradiation, and oxidation by H2O2), WP coacervates protected the vitamin against chemical degradation. B9-WP coacervates also showed considerable physical stability over time when incorporated in real food matrices. Compared to unencapsulated B9, oral administration of B9-WP coacervates to healthy rats enhanced the plasma level of the vitamin. This improved bioavailability can be ascribed to the improvement in the solubility of B9 throughout the gastro-intestinal tract. We thus demonstrate the efficiency of WP coacervates as biocarrier for the protection and delivery of small bioactive molecules.