Stability of oil-in-water (O/W) emulsions with chia (Salvia hispanica L.) mucilage

The stability of oil-in-water (O/W) emulsions prepared with different concentrations of chia mucilage extracted by two different methods was evaluated as a function of refrigerated storage time. O/W emulsions (20: 80 wt/wt) formulated with refined corn oil, chia mucilage dispersions (0.25, 0.50, 0.75 and 1.00% wt/wt) and 0.1% wt/wt of Tween 80 were stored at 4 +/- 1 degrees C for 120 days, evaluating their stability periodically. An emulsion without added mucilage was also prepared as a control. The emulsions were characterized determining the flow behavior, the evolution of the backscattering profiles (% BS), particle size distribution, and microscopic observations. Viscosity increased as increasing mucilage concentration, revealing a pseudoplastic flow behavior. The most stable emulsions during storage were those with >= 0.75% chia mucilage concentration, and those with mucilage obtained by Method II (which presents a higher level of purity than MI mucilage). All the emulsions prepared with mucilage obtained by Method II presented smaller droplet diameters ([D4,3]) than those prepared with mucilage obtained by Method I. Particle size distribution did not show important variations as a function of time, concentration and type of mucilage, presenting in general a unimodal behavior. The results suggested that the addition of chia mucilage (>= 0.75%) to O/W emulsions improved their stability against gravitational phase separation by increasing the viscosity of the aqueous phase, limiting the mobility of the oil droplets in the emulsions. (C) 2016 Elsevier Ltd. All rights reserved.