Physicochemical properties of high-pressure treated lentil protein-based nanoemulsions

The emulsifying properties of pulse proteins offer the possibility to provide functionality to colloidal food systems like nanoemulsions. The objective was to obtain stable lentil nanoemulsions through High-Pressure Homogenization (HPH) (50–300MPa) using different number of homogenization passes (1–3) and emulsifier:oil ratios (1:1, 1:2, 2:1). Oil-in-water nanoemulsions were characterized through particle size distribution, mean droplet size, polidispersity index (PdI), ζ-potential, interfacial tension (IT), stability against creaming, and flow behavior. HPH>100MPa changed particle size distribution of 1:1 lentil nanoemulsion from multimodal to bimodal, regardless of homogenization passes number. Two homogenization passes and ratios of 1:1 and 2:1 improved reduction of droplet size (587–149nm) and PdI (0.821–0.168), with no difference between those ratios. ζpotential values were lower than −30mV, which can be considered as a stable emulsion. As emulsifiers, lentil proteins decreased IT of water-oil interphase from 16.5 to<7.0mN/m, regardless pressure treatment applied. Nanoemulsions showed pseudoplastic characteristics at all experimental conditions evaluated. HPH decreased ƞapp, and higher ƞapp were observed with 2:1 ratio. Stable lentil nanoemulsions can be obtained by using 1:1 emulsif ier:oil ratio and HPH above 200MPa with two homogenization passes, which could be used as novel food systems.