Development of innovative liposome-release systems for encapsulation of biologically active soybean peptides

Abstract

Bioactive peptides constituents of protein hydrolysates show great instability, poor absorption and bitterness when incorporated into food formulations. In addition, in the gastrointestinal system, there has been noted a loss of biological activity before desorption into the bloodstream and a lack of bioactivity at the target site in the body. The latest studies have focused on the field of encapsulation of proteins and peptides and for this purpose liposomes composed of natural phospholipids, molecules of cell membrane factors, are imposed as the most suitable choice. Therefore, the aim of this research is to develop new liposome-release systems suitable for encapsulation of soy protein hydrolysates. Multilamellar liposomes were prepared by forming a uniform thin film of phospholipids, cholesterol and soy protein hydrolysates, and by a sequential hydration process. For the purpose of obtaining unilamellar vesicles, the suspension of multilamellar vesicles was treated with high-intensity ultrasound waves. Unilamellar liposomes were characterized from the standpoint of size distribution, surface charge, degree of encapsulation, stability and retained antioxidant activity. A satisfactory percentage of soy protein hydrolysates encapsulation greater than 40% was achieved for all prepared suspensions, with a significant increase in encapsulation efficiency with increasing peptide mass. All liposome formulations were characterized by a negative zeta-potential value, with an increase in the negative charge above 30 mV in the case of suspensions with 60 and 100 mg of soybean peptides indicating greater stability compared to the suspension with 20 mg. The smallest particle size (191 nm) and more uniform distribution was observed in the suspension with the highest encapsulation efficiency (56%) and stability (-33.1 mV). Retention of antioxidant activity after the encapsulation procedure in liposomes was noted. In the simulated gastrointestinal system, liposome formulations were found to provide sustained release of antioxidant peptides derived from hydrolysates, indicating their potential application in food formulations.