Studies of aggregation behaviours of cereal β-glucans in dilute aqueous solutions by light scattering: Part I. Structure effects

Cereal β-glucans form aggregates even in dilute aqueous solution. Their aggregation behaviours were studied by static and dynamic light scattering. It was shown that the aggregation of cereal β-glucans in aqueous solution was a very fast dynamic process and the equilibrium of molecular association and dissociation were reached quickly. The concentration dependence of the average apparent diameters of cereal β-glucans suggested that the cluster–cluster aggregation was dominant. The structural features of cereal β-glucans played an important role on their aggregation behaviours. As molecular weight increased, the degree of aggregation decreased due to the lower diffusion rate of large molecules. For the more rigid conformation (lower diffusion rate) of β-glucans with higher tri/tetra ratio, their degrees of aggregation were lower. These results suggested that the aggregation process was diffusion limited.