Transglutaminase–mediated engineering of myofibrillar proteins for enhanced stability and rheology in high internal phase Pickering emulsions

The primary goal of this work was to develop a sustainable protein–based fat substitute for low–fat food applications by leveraging transglutaminase (TG)–mediated structural engineering of tilapia myofibrillar protein (MP). This study investigates the structural modulation of MP by TG for constructing high internal phase Pickering emulsions (HIPPEs). TG–mediated cross–linking caused conformational changes in MP that resulted in stiff, hydrophobic–stabilized networks. The optimized HIPPEs showed shear–thinning behavior, a high elastic modulus (G′ >1000 Pa), and droplet sizes (1–10 μm). Covalent cross–linking was found to be responsible for the strong resistance to thermal treatments (≤90°C) and ionic stress in environmental stability evaluations. Nevertheless, HIPPEs showed limited freeze–thaw stability (G′ reduction from 1183.7 to 8.96 Pa) and pH sensitivity (structural collapse at extremes), underscoring the superiority of covalent networks over electrostatic forces in long–term stability. Compared with commercially available mayonnaise (with a thixotropic recovery rate close to 100%), the lower thixotropic recovery rate of HIPPEs (87.35% under the optimal MP conditions) is a significant drawback, indicating that the reversibility of its network is insufficient. This work provides a sustainable approach to low–fat food innovation by advancing the design of protein–based fat mimics through interfacial engineering. • The crosslinking effect of TG enhances interfacial rigidity and emulsion stability • HIPPEs enable paste-to-gel rheology via TG/MP optimization • Covalent TG networks enable resilience under high ionic strength and heat • HIPPEs mimic fat via shear-thinning and mayonnaise-like texture