PEA PROTEIN ISOLATE: SUSTAINABLE ALTERNATIVE TO PREPARE MICRO AND NANOEMULSIONS OF CAPSICUM BACCATUM PEPPER OIL EXTRACT

Pea protein isolate (PPI) is an interesting vegetable alternative to conventional surfactants and animal proteins considering the emulsifying properties for food applications. In addition to the valuable nutritional composition, PPI have a reduced environmental impact making it a sustainable, nutritious and safe alternative for human nutrition. The aim of this work was to evaluate the performance of PPI in the formation of stable emulsions produced with an oil extract of Capsicum baccatum pepper (OEC). The OEC was obtained with coconut oil (60%) and Capsicum baccatum powder (40%) by ultrasonic extraction (100 W/30 kHz/10 min) and homogenization with ultraturrax (5 min/ 50 °C) followed by centrifugation (4800 rpm/28 °C/ 15 min). Oil/water interfacial stress analysis was performed by the Wilhelmy plate method (at 28 °C) using an aqueous solution of PPI 0.3 g.L-1 . The interaction of PPI with the water and oil phases was analysed by the contact angle using the sessile drop method with a goniometer. A complete factorial experimental planning of type 32 with triplicate at the central point was conduct to evaluate stability at creaming (7 days at 25 oC) and droplet sizes of emulsions, using different PPI concentrations (0.5, 0.75, and 1.0% m/m) and varied ultrasound power (40; 80 and 120 W, 2 min), with fixed OEC 10%. The PPI promoted the reduction of interfacial tension from 14.65 mN/m to 3.35 mN/m, indicating that it is a promising stabilizer. The contact angle values of PPI/water (42.28°) and PPI/oil (50.25°) were similar, showing that PPI can adsorb satisfactorily in the interface. The conditions of experiment 3 (0.5 % PPI; 120 W) were more adequate with an average drop diameter of 1,251.44 ± 211.97 nm, polydispersity index (PDI) of 0.325 ± 0.002 and stability at creaming of 100% during the 7 days of storage. The conditions of experiment 9 (1 % PPI; 120 W) presented an average drop diameter of 393.23 ± 36.51 nm, PDI of 0.195 ± 0.008 and stability at creaming of 100 % during the 7 days of storage. The other experiments did not proportionate adequate stability, varying from 40% to 85%. The response surface analysis (95% significance level) showed that the intermediate concentration of PPI (0.75%) resulted in lower stability for the emulsions, while the lower ultrasound power (40 W) associated with the lower concentration of PPI (0.5 %) generated smaller droplet diameters. Further investigations are needed in order to evaluate chemical stability of OEC in the emulsions with different droplet sizes. The PPI pointed out to be a potential alternative for the stabilization of micro and nanoemulsions for application in the development of plant-based food.