Lentil protein stabilized emulsion - Impact of lecithin addition on emulsions properties

Plant-based proteins are currently the focus of a lot of product development research, as they have proved to be a potential replacement of animal-based ingredients and safeguard environmental and human health. However, most of the studies focus on soy and pea based food whereas lentil proteins have received only little attention. The aim of this work is to elucidate the behavior of different lentil protein sources (isolate, concentrate and flour) in stabilizing emulsions and to study their interaction with food emulsifiers such as lecithin. We study the adsorption kinetics at the oil water interface of both, the different protein sources as well as their combination with lecithin. Lentil protein-based emulsions (with 1%wt protein content) reveal bimodal particle size distribution and the emulsion shows various dispersion states (aggregated or well dispersed) depending on the protein sources and processing conditions. The addition of lecithin (with 0.25%wt) reduces aggregation phenomenon and reduce the average droplet size for lentil flour based emulsion. The adsorption kinetic at the oil water interface, suggest the formation of a surface active protein-lecithin complex and a mixed interfaces. Moreover, the mixture of lentil proteins and lecithin can reduce the interfacial tension by up to 12 mN/m compared to lentil protein alone. This demonstrates the presence of synergistic effects at interfaces and potential interactions between lecithin and proteins.