In-vitro digestion and fermentation of cranberry extracts rich in cell wall oligo/polysaccharides

Abstract

Cranberry extracts, generated by microwave-assisted extraction and enzymatic-treatment, were subjected to in-vitro-gastrointestinal digestion and colonic fermentation using human-fecal-inoculum. 54.3% of neutral sugars were found in jejunum dialysate, whereas 51.2% of uronic acids were recovered in effluents. Pectic polysaccharide regions of cranberry extract resisted the gastrointestinal digestion, while hemicellulosic polysaccharides were hydrolyzed. Total polyphenolic content in all digesta was 2.3 times higher as compared to feed meal. Cranberry products (pomace-extract-hydrolysate) showed different fermentation behaviors and were compared to inulin-type-oligofructose. All cranberry products improved the growth of Clostridia cluster-XIVa (Δlogbacteria = 1.3–2.5). Cranberry hydrolysate and oligofructose increased the population of Bifidobacterium spp (Δlog = 0.5–0.6). Contrary to pomace and oligofructose, cranberry extract and its hydrolysate did not enhance the growth of Enterobacteriaceae. Short-chain-fatty acid analysis revealed the production of large amounts of acetate, propionate, and butyrate with total concentrations of 145.5–161.7 mmol/L. This study lays the ground for the development of prebiotic-cranberry extracts as value-added-functional ingredients.

Keywords

• Cranberry pomace
• Cranberry extract/hydrolysate
• Cell wall oligo/polysaccharides
• In-vitro gastrointestinal digestion
• Colonic fermentation
• Gut microbiota