Composite starch/fermented protein emulsion gels for plant-based cheese applications

This work investigated the effect of incorporating lipids and proteins on the properties of starch-based gels relevant for plant-based cheese analogues. Gels were prepared by first fermenting protein-based emulsions to create primary gels, and subsequently using the water of these primary gels as starch hydration media to produce secondary, starch-based, pea protein-rich composite emulsion gels. Fermentation appeared to increase gel hardness compared to non-fermented protein addition. Compared to natural and crosslinked/acetylated starches, the acid-hydrolysed/acetylated starch produced firmer gels and was selected for further experimentation. Gels were macroscopically homogeneous but microscopically showed lipid coalescence at increasing lipid content (>8%), which was reduced by ultrasonicating the emulsion prior to fermentation. Dry matter content was key in determining textural and rheological properties of the gels, with starch/protein gels of 36% dry matter showing hardness and viscoelastic properties similar to those of the dairy cheese Danbo. However, the composite gels did not melt on increasing temperature up to 80 °C (delta below 20°). Proton dynamics were found to depend on gel properties and lipid addition. Overall, this work contributes towards the development of plant-based cheeses with desired characteristics by increasing their protein content and modulating their properties through fermentation and syneresis. • Modified & native potato starch used for composite starch/pea protein emulsion gels. • Protein was prefermented & syneresis water subsequently used to hydrate the starch. • Starch content in the aqueous phase was key in determining gel properties. • Sonication & order of addition can fine-tune gel microstructure & functionality.