Effect of Plant Protein-Based Microencapsulation on Antioxidant Capacity in Probiotic Systems

Abstract

The protection of bioactive compounds against environmental stress factors is of paramount importance in the development of functional food ingredients. This study was conducted to determine the effectiveness of microencapsulation systems based on rice protein, a plant-derived protein, and inulin, a prebiotic polysaccharide, using conjugation and physical mixing methods, and to evaluate their impact on the antioxidant capacity of systems containing different probiotic strains (Lactobacillus reuteri and Lactobacillus acidophilus). In the research, conjugate structures prepared through covalent modification of rice protein and inulin, as well as traditional physical mixtures, were utilized as wall materials. The total phenolic content of the microcapsules was analyzed using the Folin-Ciocalteu method, and their radical scavenging activities were determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The findings indicated that the total phenolic content of the microcapsules ranged from 275.94 to 291.56 milligrams of gallic acid equivalent per gram (mg GAE/g), while radical scavenging activities ranged between 157.36 and 227.54 milligrams of ascorbic acid equivalent per gram (mg AAE/g). The highest phenolic content and antioxidant potential were identified in the formulation containing Lactobacillus acidophilus prepared with the rice protein-inulin conjugate matrix (LAPC). The results of the study revealed that the covalent conjugation of rice protein and inulin strengthened molecular interactions with phenolic compounds through modifications induced in the protein structure and created a more resilient protective barrier compared to physical mixtures. These findings demonstrate that plant protein-based conjugate systems offer a superior encapsulation strategy for enhancing the oxidative stability of bioactive components in food formulations containing probiotics.