Protein-reinforced and chitosan-pectin coated alginate microparticles for delivery of flavan-3-ol antioxidants and caffeine from green tea extract

Abstract

In this study, potential interactions of alginate-proteins and proteins-polyphenols were utilized for the formulation of microparticles encapsulating green tea flavan-3-ols and caffeine. Electrostatic assisted extrusion of alginate-protein (whey proteins, bovine serum albumine, calcium caseinate, soy proteins, hemp proteins) formulations was performed for the production of microparticles and the effect of chitosan or pectin coating was evaluated. Employing alginate in combination with soy or hemp proteins provided large and hard particles, while reinforcement with whey proteins and bovine serum albumin provided the most spherical and softer particles (lower hardness and elasticity), with average diameters around 700-800 mu m. The combination of alginate and calcium caseinate or whey proteins enabled to retain the highest content of polyphenols and caffeine in the formulated particles (up to 80%). Chitosan or pectin coating did not improve the physical and morphological properties or the encapsulation efficiency, but conferred better (prolongued) release profile of polyphenols from the particles. The release studies in water and simulated gastric and intestinal fluids revealed burst release of polyphenols (over 50% in first 5-10 min) followed by sustained release up to 120 min. An artificial neural network designed based on all physical and bioactive parameters of the formulated particles, revealed that the combination of alginate with calcium caseinate or bovine serum albumin as the delivery formulation and pectin coating would provide particles with the maximum loading efficiency of green tea polyphenols and proteins as the functional components, which may facilitate their functional properties when delivered to specific target media in the organism.