Prebiotic potential of pectin and cello-oligosaccharides from apple bagasse and orange peel produced by high-pressure homogenization and enzymatic hydrolysis

Apple bagasse and orange peel were subjected to high-pressure homogenization (HPH), enzymatic hydrolysis (EH) and their combination (HPHE) to study their effect on oligosaccharide production and in vitro fermentability. The application of a cellulase-pectinase mixture on the by-products generated significant quantities of cellobiose (COS-2) and pectin derived oligosaccharides (POS) which were identified as mainly methylated and acetylated oligogalacturonides with DP 2-5 (POS 2-5). When pre-treating the substrates with HPH, the release in orange peel was enhanced significantly leading to a POS content of 44.51 g/100 g peel, whereas oligosaccharide solubilization in apple bagasse was not affected. In vitro fermentation of the hydrolysates containing COS-2 and POS showed faster fermentation rates, between 6 and 10 h, and enhanced gas production, compared to those samples not subjected to enzymatic hydrolysis. Short chain fatty acid (SCFA) production was not impacted by the presence of POS and COS-2 in the induced quantities.