Enhanced gelling properties of fava bean proteins via the addition of commercial oat β-glucan ingredients

Thickening and gelling agents are widely used to enhance the texture of plant-protein gels. With the rising demand for sustainable and clean-label formulations, fibres such as oat β-glucan (BGL) are being explored as natural additives. Here, two commercial oat β-glucan (BGL) rich ingredients, called SD and PO (varying in BGL content), were used to investigate which properties and concentrations most influenced the gelling of fava bean protein isolate (FPI). The addition of BGL powder to a fixed 15 wt% protein concentration resulted in enhancements mainly for the gel stiffness from 16.5 ± 1.7 kPa to 92.2 ± 7.2 kPa with SD and 39.3 ± 3.8 kPa for PO. BGL content corrections did not reveal clear differences for SD and PO addition. With 5 % BGL powder addition and varying protein content, the maximum increase in the Young's modulus was 16.3 and 6.9 times for SD and PO at peak, respectively. Fracture stress increased up to 13.3 and 3.6 times. The minimum gelling concentration was reduced from 12 wt% to 8 wt% and to 9 wt% when 5 % SD or PO was used, respectively. When corrected for the dry matter content and BGL content, the results revealed that only SD enhanced the gelling properties. The effect was explained by most pronounced microphase separation for SD which was related to differences in purity (67 wt% vs 26 wt%), molecular weight (67 kDa vs > 550 kDa), and viscosity (0.17 Pa.s vs 11 Pa.s) for SD and PO, respectively.