Development of lentil aquafaba-based emulsions with the addition xanthan gum or corn starch for food technology applications

Introduction: Currently, there is an increasing trend towards the use of functional w/o emulsions for food applications based on plant proteins from aquafaba legumes.

Goal: The evelopment of stable w/o emulsions containing 30 and 60% sunflower oil for applications in emulsion-like functional foods. Lentil aquafaba with 0.5 and 0.8% protein was used as a vegetable emulsifier, and xanthan gum (0.1 and 0.2%) or cold-soluble corn starch (1 and 2%) thickeners were added to physically stabilize the emulsion.

Methods: The stability of the emulsions was assessed based on both the volumetric droplet size distribution and the apparent viscosity measured by laser diffraction and rotational viscometry, respectively.

Results: Preliminary studies of the technological properties of lentils, such as swelling and boiling coefficients, seed strength before and after heat treatment, and the diffusion coefficients of soluble solids in water, allowed us to optimize the aquafaba production process. Emulsions with lentil aquafaba as an emulsifier show a bimodal droplet size distribution. The average volumetric size depends on the thickener concentration and changes for emulsions with 60% oil from 8.2 μm (with 0.2% xanthan) to 29.3 μm (with 2% starch). The same trend is observed for emulsions with 30% oil. Rheological studies allowed us to classify the samples as non-Newtonian fluids with a pseudoplastic flow pattern. Fitting the flow curves to the Herschel–Bulkley model allowed us to calculate the yield shear stress for the emulsions, which varied from 0 to 6.8 Pa depending on the oil content and the nature and amount of the thickener. For emulsions with 30% oil and starch as a thickener, instability was visually observed over time, and afterwards the emulsion was degraded.

Conclusion: Food emulsions obtained using plant proteins of lentil aquafaba as an unconventional emulsifier are promising ingredients in the formulation of emulsion-based foods.