Effect of texture and structure of polysaccharide hydrogels containing maltose on release and hydrolysis of maltose during digestion: In vitro study

The release and hydrolysis of maltose from six classic polysaccharide-based hydrogels (agar, low acyl gellan, κ- and ι-carrageenan, sodium alginate and konjac glucomannan) containing 1% gelling agent and 10% maltose were compared under sequential in vivo oral, simulated gastric (SGD) and intestinal digestions (SID). The incorporation of maltose into hydrogels obstructed up to 35% maltose digestion and reduced the early stage of maltose hydrolysis by 40%–60%. The degree and the nature of obstruction were dependent on the polysaccharide structure and gel texture. Limited fragmentation of elastic and cohesive hydrogels and reduced maltose release in highly adhesive hydrogels both resulted in lower maltose release at the oral phase. The remaining large gel particles and dramatic gel microstructural changes as response to the gastric pH limited maltose release at SGD. Cumulative maltose release from oral processing and SGD contributed to initial maltose hydrolysis rate (HR) and the overall maltose hydrolysis in SID. Additionally, other factors were also involved. Release of polysaccharide from hydrogels under SGD stress and the formation of fine gel particles may have resulted in highly viscous or viscoelastic intestinal fluid and therefore decreased the speed of enzyme reaction. We believe that the information provided by the current study would help future design of hydrogel texture targeted at different incipient food component release and digestion profiles.