Interaction between cereal β-glucan and proteins in solution and at interfaces

Cereal β-glucan is well known for its beneficial health effects, such as lowering of blood cholesterol values and a reduced risk of coronary heart disease. These effects are often discussed in relation to the dissolution and aggregation behavior of the β-glucan during human digestion. Furthermore, potential proteinaceous material present is believed to have an important impact on the formation of viscous slurries during digestion and might influence the aggregation behavior of the β-glucan. Therefore, the interaction and aggregation behavior of a β-glucan isolate (OBC90) with two different proteins (gliadin and whey protein) was investigated in solution at different pH with regards to kinetics of aggregation and protein/β-glucan ratio and at interfaces. Aggregates were found at low pH and the aggregation and composition of aggregates seems to depend on the type of protein. Furthermore, phosphate was found at low concentrations in the β-glucan, most likely being the reason for the net negative charge at pH ≤ 4. Therefore, electrostatic interaction is suggested to play an important role for the aggregation between β-glucan and proteins.