Squalene encapsulation by emulsification and freeze-drying process. Effects on bread fortification

Abstract

In the present work, squalene (SQ) was encapsulated by a conventional emulsion method using egg white protein nanoparticles (EWPn), as a high molecular weight surfactant, followed by a freeze-drying process to obtain an SQ powder ingredient. EWPn was produced by heat treatment at 85 °C, 10 min, and pH 10.5. EWPn showed higher emulsifying activity compared to native EWP highlighting their potential to be used for the SQ encapsulation by an emulsification process. Firstly, the encapsulation conditions were studied by using pure corn oil as an SQ carrier. The explored conditions were oil fraction (0.1-0.2), protein amount (2-5% wt.), homogenization pressure (100 and 200 bar), and maltodextrin amount (10-20% wt.). The highest encapsulation efficiency was reached for 0.15 oil fraction, 5% wt. protein concentration, 200 bar homogenization pressure, and 20% maltodextrin. Then, SQ was encapsulated using these conditions to obtain a freeze-dried powder ingredient, which was added to a bread formulation. The total and free oil of SQ freeze-dried powder was 24.4 ± 0.6% and 2.6 ± 0.1%, respectively, resulting in an EE value of 89.5 ± 0.5%. The physical, textural, and sensory properties of functional bread were not affected by the addition of 5.0% SQ freeze-dried powder. Finally, the bread loaves showed higher SQ stability compared with the one formulated with unencapsulated SQ. Hence, the encapsulation system developed was suitable for the obtention of functional bread based on SQ fortification.