Design of the new particles for controlled release of bioactive peptides

Abstract

Bioactive peptides carry antioxidative activity and have the potential to be used as additives in food formulation. When incorporated, major instability of peptides is imposed within heterogeneous products, as well as the loss of biological activity in the gastrointestinal system before absorption into the bloodstream and manifestation of biological activity at the target site in the body. A good solution as a controlled release system is liposomes – particles made out of phospholipids, natural molecules and a building block of the cell membrane. Therefore, the aim of this study was to prepare new systems for the encapsulation and controlled release of soybean antioxidant peptides. Liposome preparation was performed by forming a uniform thin film of phospholipon 90-G and hydrating it with an aqueous solution of soy protein concentrate hydrolyzate prepared by a two-step enzymatic process. The last step of liposome preparation was ultrasonic treatment. The size distribution, surface charge, degree of encapsulation and stability of multilamellar liposomes were characterized. A thin film method provided a satisfying percentage of encapsulation of soybean antioxidant peptides (19%). The ultrasonic homogenizer proved to be three times better than the ultrasonic bath while reducing the size of the particles. The antioxidant activity was tested by neultralization of the ABTS • + radical cation method and by Fe2+ ion chelation method. The test have shown that encapsulation of the peptide activity was partially retained. In the simulated gastrointestinal system, diffusion experiments have shown that liposomes slow down the release of antioxidant peptides. The presented results represent important information for the specific application of liposomes with encapsulated soybean peptides in functional food products.