Influence of polysaccharide concentration on polyphenol-polysaccharide interactions

Non-covalent interactions between polysaccharides and phenolics affect the physical properties of polysaccharide solutions. These interactions may in turn be influenced by polysaccharide-polysaccharide interactions. To test this hypothesis, we studied the influence of polysaccharide concentration (with guar, β-glucans, and xanthan) on the variations of rheological and water-binding properties upon addition of phenolics compounds (vanillin, caffeic acid, gallic acid, and epigallocatechin gallate). Addition of phenolics led to increased flow behavior index and decreased flow consistency index, with maximum effects at polysaccharide concentrations ranging between 0.6 × C* and 1.4 × C*, where C* is the critical overlap concentration of each polysaccharide. Water mobility was generally not significantly influenced by the addition of phenolics. The results showed that the ability of phenolic compounds to induce aggregation of polysaccharides in solution was strongly influenced by polysaccharide concentration around C* and therefore by polysaccharide-polysaccharide interactions.