Pectin-non-starch nanofibers biocomposites as novel gastrointestinal-resistant prebiotics

•Novel biocomposites based on prebiotic nanofibers were fabricated to protect probiotics.•Nanofibers of chitin, lignocellulose and bacterial cellulose improved pectin biocomposites.•Prebiotic activity and gastrointestinal resistance of the biocomposites were optimized.•Survival of B. coagulans included in the biocomposites to GI conditions was enhanced.•The biocomposites presented a good structural integrity with a non-porous surface.

Incorporation of nanofibers of chitin (NC), lignocellulose (NLC) and bacterial cellulose (BNC) in pectin was studied to improve prebiotic activity and gastrointestinal resistance of the pectin-nanofibers biocomposites for protection of probiotics under simulated gastrointestinal conditions. The biocomposites were prepared using various compositions of pectin and nanofibers, which were designed using D-optimal mixture method. The incorporation of the nanofibers in pectin led to a slow degradation of the pectin-nanofibers biocomposites in contrast to their rapid swelling. AFM analysis indicated the homogenous distribution of interconnected nanofibers network structure in the pectin-nanofibers biocomposite. FTIR spectra demonstrated fabrication of the biocomposites based on the inter- and intra-molecular hydrogen bonding and ionic interaction of pectin-Ca2+. XRD patterns revealed the amorphous structures of the biocomposites as compared to the crystalline structures of the nanofibers. Among the compositions, the optimal compositions were as follows: 60% pectin + 40% NC, 50% pectin + 50% NLC and 60% pectin + 40% BNC, where the prebiotic score, probiotic survival under simulated gastric and intestinal conditions were optimum. The optimal biocomposite pectin-NC exhibited the highest survival of the entrapped probiotic bacteria under simulated gastric (97.7%) and intestinal (95.8%) conditions when compared with the corresponding to free cells (76.2 and 73.4%).