Effect of Maillard reaction on rheological, physicochemical and functional properties of oat β-glucan

Three types of oat β-glucan conjugates were prepared through Maillard reaction between oat β-glucan and l-glutamine (dipeptiven and l-glutathione). The structural properties of the β-glucan conjugates were compared using Fourier transform infrared spectroscopy (FT-IR), and their molecular weights were determined by gel permeation chromatography (GPC). The rheological property, emulsifying property, swelling power, and fat binding capacity of β-glucan conjugates were evaluated. The results indicated that the β-glucan conjugates were successfully obtained by bonding β-glucan with the amino acid/peptides. The molecular weight of oat β-glucan, and its conjugates with l-glutamine, dipeptiven, and glutathione was 119.5, 295.5, 317.6, and 321.0 kDa, respectively. β-glucan conjugates (5% w/v) exhibited a shear thinning behavior at 20 °C when oat β-glucan showed Newtonian fluid behavior over the entire measured shear rates. The apparent viscosity of oat β-glucan increased largely after Maillard reaction, and the β-glucan-dipeptiven conjugate (βG-D) showed the highest apparent viscosity. The emulsifying property, swelling power and fat binding capacity of β-glucan conjugates were enhanced compared with that of oat β-glucan, and βG-D showed the highest emulsifying property, swelling power and fat binding capacity. This phenomenon might be related to the fact that βG-D possessed highest apparent viscosity. The results revealed the possible changes of oat β-glucans during food processing, and will provide theoretical supports for the application of β-glucans as functional ingredients for food industry.