Abstract
In this study, we developed novel porous starch (PS)/Lactobacillus (LS) microcapsules via in situ cross-linking with sodium trimetaphosphate (STMP), using Lactobacillus johnsonii (LJ), Lactobacillus acidophilus (LA), and Lactobacillus rhamnosus GG (LGG) as representative strains. Scanning electron microscopy (SEM) revealed that the cross-linked microcapsules (designated as PS/LS-CL: PS/LJ-CL, PS/LA-CL, PS/LGG-CL) formed aggregated structures with denser microarchitecture compared to uncross-linked porous starch/Lactobacillus microcapsules (designated as PS/LS: PS/LJ, PS/LA, PS/LGG). The encapsulation efficiencies of PS/LJ-CL, PS/LA-CL, and PS/LGG-CL (79.56%, 78.49%, and 55.96%, respectively) significantly surpassed those of their uncross-linked counterparts (67.92%, 58.68%, and 47.71%, p < 0.05). In addition, the cross-linked porous starch microcapsules improved the survival rate of Lactobacillus during simulated gastrointestinal digestion and long-time storage. Importantly, the oral gavage of PS/LS-CL, PS/LA-CL, and PS/LGG-CL significantly increased the amount of Lactobacillus. The colonization efficiency of all the tested Lactobacillus in mice was detected by both gradient dilution plate counting and quantitative real-time PCR (qRT-PCR). These findings indicate the potential function of the in situ cross-linked porous starch microcapsules as a robust delivery system to enhance the colonization of probiotics in vivo.