Carboxymethyl chitosan/N-acetylneuraminic acid/oxidised hydroxyethyl cellulose hydrogel as a vehicle for Pediococcus pentosaceus RQ-1 with isomaltose-oligosaccharide: Enhanced in vitro tolerance and storage stability of probiotic

C-NeuAc/OHEC hydrogels were prepared from carboxymethyl chitosan/N-acetylneuraminic acid (C-NeuAc) and oxidised hydroxyethyl cellulose (OHEC), and used as novel vehicles for the co-encapsulation of Pediococcus pentosaceus RQ-1 and isomaltose-oligosaccharide (IMO). The thermal stability, rheological behaviour, swelling kinetics, porosity, pH sensitivity, and degradability of the hydrogels were evaluated. The hydrogels were most stable and were suitable as vehicles for co-encapsulation of Pediococcus pentosaceus RQ-1 and IMO when C-NeuAc:OHEC = 5:4. In the presence of IMO, the encapsulation efficiency of the hydrogel was optimal and in the range of 91.02–94.63%. An in vitro assay revealed that the C-NeuAc/OHEC hydrogel provided good protection for Pediococcus pentosaceus RQ-1 against the harsh conditions of a simulated gastrointestinal tract. The survival rate of Pediococcus pentosaceus RQ-1 was only 77.0% in the presence of free IMO. By contrast, the survival rates of Pediococcus pentosaceus RQ-1 co-encapsulated with 0.5%, 1.0%, and 1.5% IMO were 84.4%, 90.8%, and 90.3%, respectively. Hence, IMO co-encapsulation significantly improved probiotic survival. Moreover, co-encapsulation with 1.0% IMO and 4 °C were the optimal storage condition for Pediococcus pentosaceus RQ-1. The present work showed that C-NeuAc/OHEC hydrogels are promising as probiotic co-encapsulation delivery vehicles.