Pea protein microgels: microparticulation process development, evaluation of technofunctional properties, and application as Pickering emulsion stabilizers

Abstract

Nowadays, the consumer's choice for food products is beyond the nutrition aspect. Factors such as environment sustainability and ethical principles during the processing are even more linked to their buying decision. This fact has been pushing forward the food industry to rethink their formulations, choosing to develop products that fit better to this new consume profile. One of the strategies to achieve such aim is the replacement of animal proteins for vegetal proteins into food formulations. However, protein from vegetables presents techno functional properties distinct from animal proteins, manly due to their low solubility. Some interventions may be performed in order to improve the techno functional properties of vegetal proteins by using physical or chemical methods or by enzymatic reaction. Microparticulation is a physical process conduced by heat, which induces protein molecules aggregation, followed by a shear step to promote disruption of aggregates, enabling the production of structures known as microgels. Protein microgels can be applied to modulate food structures, to mimic fat globules in low fat products, and to stabilize interfaces. The latter property is especially favourable to the creation of Pickering emulsion. Microgels' versatility demonstrates their complexity and potential of application. In view of that, this post-doctoral project has as objective to study the effects of microparticulation on pea protein flexibility and techno functional properties, as well as to evaluate the impact of a post-treatment technique on their characteristics. Pea proteins will be extracted at lab scale, and their microparticulation will be consisted of an enzymatic protocol together with a heat treatment. The obtained microgels will be characterized regarding to their physical, chemical, and conformational structures, besides the evaluation of their flexibility and techno functional properties (solubility, interfacial and rheological properties). The formulation containing microgels with increased flexibility and more adequate techno functional properties will pass trough and post-treatment step (spray drying), followed by its characterization by using the same criteria described previously. Thereby, it is intended to evaluate the effect of drying process parameters on the properties of the produced microgels. Finally, the applicability of those microgels will be evaluated by producing Pickering emulsions, where the continuous phase will be composed by the microgel dispersion. The Pickering emulsions will be evaluated regarding to their physical properties, stability during storage, and rheological properties. (AU)