Structurally Different Pectic Oligosaccharides Produced from Apple Pomace and Their Biological Activity In Vitro

Abstract

This study set out to identify the composition and the biological activity of pectin-derived oligosaccharides (POS) generated from mild acid or enzymatic hydrolysis of apple pomace (AP). The effect of the polymerization of the structural units of POS contained in the AP hydrolysate on the growth and metabolism of microbiota from the human gastrointestinal tract and the adhesion of lactic acid bacteria (LAB) or pathogens to human gut epithelial cells was investigated in vitro. Mild acid hydrolysis followed by pectinolysis with Rohapect MaPlusT yielded the highest concentration of POS. In contrast, pure enzymatic processing of the AP performed with a mixed preparation of cellulase and Rohapect MaPlusT resulted in 1.8-fold lower overall POS. The concentration of higher-order oligosaccharides (degree of polymerization (DP) 7–10), however, was 1.7-fold higher. The increased ratio of higher-order oligosaccharides caused an increase in the bifidogenic effect, as well as affecting the amount and nature of short-chain fatty acid produced. Inhibition of Enterobacteriaceae was also observed. The strongest stimulation of LAB adhesion to the human epithelial cells occurred in the presence of the preparation containing the highest concentration of higher-order oligosaccharides. The fecal bacteria and pathogens showed much weaker adhesion to intestinal cells in the presence of all the tested AP hydrolysates. Both of the tested POS preparations, containing structurally different oligosaccharides (DPs 2–10 with different ratios of higher-order oligosaccharides), have the potential to be used as prebiotics for humans and animals. They stimulate bowel colonization with lactic acid bacteria and inhibit the development of infections caused by pathogens.

The effects of different dietary fiber pectin structures on the gastrointestinal immune barrier: impact via gut microbiota and direct effects on immune cells

“…Several studies have demonstrated that pectins and pectic-oligosaccharides (POS) have the ability to block the adhesion of pathogens to epithelial cells 99,[119][120][121] . POS are known to reduce the adhesion of pathogenic bacteria, such as Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Campylobacter jejuni, to epithelial cells [122][123][124] . This anti-adhesive effect of pectins and POS on pathogens was higher with pectins with a lower molecular weight or DM3 or DM5 pectins 119,121 .…”

“…In contrast to the anti-adhesive effects of pectins on pathogens, stimulating adhesion of commensal bacteria to epithelial cells may be favorable, as commensal bacteria may compete with pathogens for attachment or secrete other beneficial products 118 . Several studies have shown that pectins or pectic oligosaccharides enhance the adherence of commensal or probiotic Lactobacilli strains to epithelial cells 122,124 . The effects were species dependent, as pectins enhanced the adhesive effects of some Lactobacillus species, such as Lactobacillus plantarum 0981, 0995 or Lactobacillus brevis 0983, whereas pectins decreased the adhesion of other Lactobacillus species, such as Lactobacillus paracasei 0985, Lactobacillus plantarum 0989, 0990, and 0996 122 .…”

“…Several studies have shown that pectins or pectic oligosaccharides enhance the adherence of commensal or probiotic Lactobacilli strains to epithelial cells 122,124 . The effects were species dependent, as pectins enhanced the adhesive effects of some Lactobacillus species, such as Lactobacillus plantarum 0981, 0995 or Lactobacillus brevis 0983, whereas pectins decreased the adhesion of other Lactobacillus species, such as Lactobacillus paracasei 0985, Lactobacillus plantarum 0989, 0990, and 0996 122 . The structural characteristics were, however, not specified in those studies.…”

Bioactivity and Sensory Properties of Probiotic Yogurt Fortified with Apple Pomace Flour

“…On the other hand, Fernandes et al [5] demonstrated that in comparison to plain yogurt, yogurt supplemented with AP hot water extract (3.3%) decreased S. thermophilus counts at the end of fermentation. Furthermore, it has been shown that pectin-derived poly-and oligosaccharides isolated from AP exhibited a prebiotic effect, improving the vitality and adhesion of different lactic acid bacteria, while simultaneously reducing the adherence of various enteric pathogens [8,38].…”

“…Also, AP decreases the risk of colon cancer [ 7 ]. Furthermore, AP may serve as a carrier of phytochemicals and a source of non-viable nutrients that stimulate the numbers and/or activities of probiotic bacteria, causing the limitation of intestinal pathogen growth [ 8 ].…”