Production of O/W emulsions containing astaxanthin by repeated Premix membrane emulsification

Oil-in-Water (O/W) emulsions are mainly produced by application of high mechanical stress or by membrane emulsification processes at low pressures. Advantages such as narrower droplet size distribution and lower operating costs make membrane emulsification processes more suitable for producing astaxanthin-loaded O/W emulsions. The characteristics of 1 of these membrane emulsification methods, called repeated premix membrane emulsification, are studied in this work. In this emulsification process, a pre-emulsion is repeatedly pushed through a hydrophilic or hydrophobic membrane. In this research, a hydrophilic membrane was used because the objective was to obtain an O/W emulsion. Pre-emulsions were produced by dispersing palm off containing dissolved astaxanthin in water. The oil droplets were stabilized with a combination of 2 emulsifiers. Each O/W emulsion passed the membrane 3 times under pressures and disperse phase fractions of 5 to 15 bar and from 10 wt% to 40 wt%, respectively. To investigate the production of O/W emulsions by repeated premix membrane emulsification, mean Sauter diameters and fluxes were measured. To find the optimal ranges of pressure and dispersed phase fraction, a 2-level factorial design with central composite and stars points experimental design was applied.