Developing concentrated emulsion gel hybrids structured by natural food fibres

Abstract

The integration of healthy unsaturated fat into plant-based meat alternatives is being advocated worldwide but remains technically challenging, due to limitations in the textural qualities and processability of edible oil. One way to improve the rheological behaviour of oil is via emulsion gel technology. However, adaptable solutions for real-life food processing are few and far between. On this basis, we formulated physically stable emulsion gel hybrid templates with 50–83% sunflower oil load, mostly oil-in-water microstructure, and structured solely by natural food fibres without using oleogelators. The fibres included citrus fibre and soy polysaccharides as emulsifying fibres, and curdlan and deacetylated konjac glucomannan as structuring fibres. Upon heating, they developed stiffness up to 10E4 Pa in storage modulus G′. Here, we present the first characterisation of such fibre-based emulsion gel hybrids through analysis by epifluorescence microscopy, oscillatory rheology, and diffusing wave spectroscopy, and report underlying composition-structure-rheology-thermal behaviour relations. The key findings are that strength in the emulsion gel hybrid could come from combinations of the following observed mechanisms: (i) tiny droplets of dispersed phase droplets with high curvature, (ii) emulsifying fibre of high molecular weight, (iii) controlled interference from emulsifying fibre on the viscoelastic network development of structuring fibre, and (iv) for additional shear stability, highly aggregated state of dispersed phase droplets without coalescence. Promising templates bearing close resemblance to animal fat references such as pork belly fat (in terms of G′), and shear stability with potential toward extrusion and food printing application have been identified.