Prunus mume Concentrate and Ca2+ Dual Cross-Linking Facilitate Sodium Alginate/Carboxymethyl Chitosan/Gelatin Microcapsules for Probiotic Encapsulation

This study presents a novel dual cross-linking method using Prunus mume concentrate (PMC) as a source of H+ and Ca2+ to enhance polysaccharide (sodium alginate/carboxymethyl chitosan/gelatin) microcapsule formation. The structure and release characteristics of microcapsules were influenced more by PMC pH than by its concentration. SEM results showed that as the pH decreased, the microcapsules had a more compact structure. The FTIR results showed that acid enhances hydrogen bonding and electrostatic interactions within the polysaccharide, leading to more stable microcapsule structures. XRD patterns showed that acid enhanced the stability of the polysaccharide crystal structure. Microcapsules significantly increased viable counts by 1 log(CFU/mL) in simulated gastric fluid (SGF) and 1.25 log(CFU/mL) in simulated intestinal fluid (SIF) after 3 h of digestion. This study provides a basis for investigating the dual cross-linking of natural plant concentrates and Ca2+ construction of polysaccharide microcapsules to enhance probiotic resistance.