Fabrication of a double-network high internal phase emulsion gel stabilized by bacterial cellulose nanofibrils: Enhancement of heat stability and 3D printing

Abstract

The semi-fluid properties required for 3D printing of high internal phase emulsion (HIPE) gels are incompatible with high mechanical strength, thereby limiting the application of HIPE gels in simulated meat products. In this study, pea protein (PeaP)-stabilized HIPEs reinforced with bacterial cellulose nanofibrils (BCNFs) were constructed and deformed into PeaP/sodium alginate (SA) double-network HIPE gels by further cross-linking of transglutaminase (TGase) and Ca2+. Increasing the BCNF concentration decreased the interfacial tension of water-in-oil HIPE emulsions from 11.91 mN/m to 9.49 mN/m, and reduced the average diameter of the droplets from 27 ± 3.1 μm to 11.3 ± 0.6 μm. The HIPEs also showed a thicker interfacial layer and improved viscoelastic properties at higher BCNF concentrations. The HIPEs were transformed from a semi-solid material to a rigid solid HIPE gel after the formation of a double-network structure. The fracture stress of the double-network HIPE gel containing 0.16% BCNFs was 0.015 MPa, which was greater than that of 0.001 MP and 0.007 MPa for the single-network SA and PeaP HIPE gels. The double-network HPIE gels fabricated with 0.08%–0.16% BCNF concentrations had high-temperature stability. The synergistic effect of the PeaP covalent network and the SA-Ca2+ ionic network produced a HIPE gel with good extrusion printability and strong self-supporting properties. This work could provide new insights into the design of high-strength HIPE gels with 3D printability that will facilitate the use of emulsion gels in plant-based meat products.