Improved thermal gelation of oat protein with the formation of controlled phase-separated networks using dextrin and carrageenan polysaccharides

• Phase separation produced by dextrin or carrageenan increased the oat gel strength.
• The type of polysaccharide used produced different degrees of phase-separation.
• Strong repulsive forces resulted in a greater degree of phase-separation and a highly ordered protein network.
• Oat protein gel strength doubled in the presence of carrageenan at neutral pH.

The thermal gelation of oat protein (OP) was investigated in the presence of polysaccharides at different pHs. The compressive stress dramatically increased in these phase-separated protein–polysaccharides gels due to an apparent increase in protein concentration. The polysaccharide structure significantly affected the degree of phase-separation and gel mechanical properties. The observed two-fold increase in gel compressive stress can be attributed to strong repulsive forces caused by carrageenan molecules. These resulted in a greater degree of phase-separation with the formation of carrageenan rich domains embedded in the protein phase, and a highly ordered protein network, stabilized by hydrogen and hydrophobic interactions. In the case of OP-dextrin gels, the rate of phase separation was slower than the rate of protein aggregation, thus the dextrin particles were uniformly distributed within the protein network. This research contributes to the basic understanding required for designing textures for novel plant-based protein products.