Novel carboxymethyl chitosan/N-acetylneuraminic acid hydrogel for the protection of Pediococcus pentosaceus

In this study, carboxymethyl chitosan (CMCS) and N-acetylneuraminic acid (NeuAc) were used to develop CNeuAc hydrogels to encapsulate Pediococcus pentosaceus QK-1. The mechanical properties, thermal stability, in vitro degradation, and pH sensitivity of the hydrogel were evaluated. The C-NeuAc concentration required for optimal hydrogel performance was 3% (w/v). Hydrogel swelling behaviour was effectively assessed by Fickian diffusion and Schott's second-order kinetic models. The hydrogel demonstrated excellent biocompatibility and low in vitro cytotoxicity. An in vitro assay revealed that the viability of Pediococcus pentosaceus QK-1 in C-NeuAc had decreased by only 1.41 log (CFU/ mL) after exposure to simulated acidic gastric fluid. Moreover, the survival rate of the encapsulated and free Pediococcus pentosaceus QK-1 cells were 80.1% and virtually zero, respectively, after passage through the gastrointestinal tract. It was empirically determined that low temperature and freezedrying were the ideal condition and method to ensure storage longevity of the hydrogel-encapsulated probiotic. Hence, C-NeuAc hydrogel is highly desirable as a food-grade probiotic delivery vehicle.

Automated summary

In this study, CNeuAc hydrogels were developed using CMCS and NeuAc to encapsulate Pediococcus pentosaceus QK-1. The hydrogel demonstrated optimal performance at a C-NeuAc concentration of 3% (w/v), and showed excellent biocompatibility and low cytotoxicity. It also effectively protected the viability of the probiotic in simulated gastric fluid and gastrointestinal tract.