The digestibility of mulberry fruit polysaccharides and its impact on lipolysis under simulated saliva, gastric and intestinal conditions

• Mulberry fruit polysaccharides (MFPs) digestion was studied in vitro.
• Salivary amylase has no effect on the polysaccharide digestion.
• The breakdown of glycosidic bonds linked to the decrease of MFPs molecular weight.
• Polysaccharide inhibit the lipid digestion in the oral and gastrointestinal tract.

The digestibility of mulberry fruit polysaccharides (MFPs) and its effect on lipid digestion were investigated in the simulated saliva, gastric and intestinal model. Results showed that the saliva, especially the salivary amylase had no effect on MFPs, while the gastric juice had greater effects on the MFPs digestion than intestinal juice, which could be evidenced from the decrease in molecular weight (Mw) from 128.7 ± 6.1, 13.6 ± 1.4 and 2.9 ± 0.1 to 84.3 ± 4.7, 5.2 ± 0.1 and 1.2 ± 0.1 KDa, respectively. It was observed that the amount of reducing ends were increased from 0.051 ± 0.003 to 0.451 ± 0.011 mM and no monosaccharide was released from the polysaccharide during the whole digestion period, indicating that gastrointestinal digestion cleaves the glycosidic bonds and produces no free monosaccharide. In addition, under the simulated saliva, gastric and intestinal digestion conditions, MFPs could reduce the rate and extent of lipid digestion in a concentration-dependent manner. Our findings provide information on the digestibility of polysaccharides from Morus nigra L. in vitro.

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