Complex coacervation systems based on a novel natural polymer (Brea gum) for encapsulation of hydrophobic materials

Abstract

Brea gum (BG) is an underexplored polymer with promising functional properties. While structurally similar to gum arabic, BG contains a higher protein fraction (5.9–7.5 %), which enhances its interfacial activity, improving emulsifying and encapsulating performance. These characteristics position BG as a potential, more cost-effective alternative to gum arabic, whose widespread use is often limited by high and unstable pricing. This research studied the complex coacervation between BG and two proteins, whey protein isolate (WPI) and gelatin (GEL). The optimum coacervation pH was 3.5 for both systems, while the highest yield was obtained at 1:3 and 1:1 ratios for BG-WPI and BG-GEL systems, respectively. FTIR analysis confirmed the complex coacervation, revealing the involvement of hydrogen bonding and electrostatic interactions. Then, coacervates were employed to encapsulate corn oil, forming multinuclear microcapsules with different morphologies and size polydispersion. BG-WPI microcapsules exhibited high porosity, resulting in high free oil and low encapsulation efficiency (EE) percentages. For BG-GEL microcapsules, low free oil (<10 %) and high EE (82.81 %) values were determined, indicating a successful encapsulation related to the more resistant walls formed by coacervation/gelation. Our findings indicate that BG is a valuable material for preparing complex coacervates.