Influence of cobalt source irradiation modification of pectin on anthocyanin stability

Abstract Objectives Influence of cobalt irradiation modification of pectin on anthocyanin stability. Materials and Methods We evaluated the stability of pectin–anthocyanin complexes formed after irradiation with varying doses of cobalt-60 under different storage, light, heat, vitamin C, and sucrose conditions. To assess the binding affinity between pectin and anthocyanins, we measured the encapsulation efficiency (EE), loading capacity (LC), zeta potential, particle size, polydispersity index (PDI), and ultraviolet-visible (UV-Vis) spectra of the complexes. Changes in anthocyanin stability were verified by determining color parameters, retention rates, and polymeric colors. Furthermore, to elucidate the mechanism by which irradiation alters the pectin structure, we analyzed its microscopic morphology, Fourier transform infrared spectroscopy (FTIR), molecular weight, and monosaccharide composition. Results Low-dose cobalt-60 irradiation caused moderate fragmentation of pectin chains. This structural modification enhanced the interaction between pectin and anthocyanins, leading to the formation of composite particles of uniform size and improved dispersion. Additionally, irradiation increased the zeta potential of the system, thereby improving anthocyanin stability. Conclusions Low-dose cobalt-60 irradiation significantly enhanced anthocyanin stability under various environmental stressors. This improvement can be attributed to structural modifications in pectin—specifically, the cleavage of its molecular chains induced by irradiation. Such degradation exposed additional binding sites on pectin, which in turn promoted the formation of a more stable pectin–anthocyanin complex. Consequently, the enhanced stability of anthocyanins was closely associated with these structural changes and the resulting stabilized complex.