Digestive and fermentative properties of hawthorn pectic polysaccharides and immunostimulatory effects of fermentation products

Hawthorn has been traditionally used in Chinese food and medicine, with pectic polysaccharides exhibiting multiple health benefits. This study focused on a homogalacturonan-enriched pectic polysaccharide (HPS) from the new Crataegus pinnatifida cultivar Jinruyi. HPS had a molecular weight of 267 kDa and was composed of rhamnose (Rha), galacturonic acid (GalA), glucose (Glc), galactose (Gal), xylose (Xyl), and arabinose (Ara), with GalA comprising 80.05 %. It was partially depolymerized during simulated digestion and highly fermentable during in vitro human fecal fermentation. Like other polysaccharides, HPS promoted short-chain fatty acid production, but, unlike neutral sugar-rich polysaccharides that mainly increase propionate and butyrate, HPS significantly enhanced acetate levels. HPS also increased beneficial bacteria such as Faecalibacterium . Additionally, HPS fermentation enhanced nitrogen monoxide (NO), reactive oxygen species (ROS) generation, phagocytic activity and cytokine generation in RAW 264.7 cells. These results suggest HPS may improve gut health by modulating gut microbiota and producing beneficial fermentation products. • Hawthorn fruit from Jinruyi was rich in homogalacturonan-type pectic polysaccharides. • HPS was partially depolymerized during saliva-gastrointestinal digestion. • HPS was further metabolized by gut microbiota, leading to increased SCFA, particularly acetic acid. • Fermented HPS exhibited better immunostimulatory activity than native HPS.