Complex coacervates of β-lactoglobulin/sodium alginate for the microencapsulation of black pepper (Piper nigrum L.) essential oil: Simulated gastrointestinal conditions and modeling release kinetics

This study evaluated the most appropriate conditions (pH and biopolymers ratio) for the formation of the complex between beta-lactoglobulin (beta-lg) and sodium alginate (NaAlg). Furthermore, we microencapsulated black pepper essential oil (EO) using these biopolymers and transglutaminase as a cross-linking agent, and stability during in vitro digestion and its release in food models were studied. A ratio of 17:1 (beta-lg/NaAlg) at a pH of 4.5 was the optimal condition for the formation of the complex. The encapsulation efficiency (85.01% +/- 0.26) and chemical and morphological characteristics suggested that black pepper EO was microencapsulated using polymers and cross-linking agent naturals. The particle size demonstrated that the capsules produced were on micro scale. The black pepper EO microcapsules lost lower release in water, and the Rigger-Peppas model indicated that the Fickian diffusion mechanism occurred. The microcapsules demonstrated a low release of black pepper EO during oral and gastric digestion and a higher release in intestinal digestion. The black pepper EO after digestion presented high stability (84.8% +/- 0.07), and bioaccessibility (31.16% +/- 0.3). The results suggest that the black pepper EO was microencapsulated and, preserved in aqueous food model and during oral and gastric conditions tested in vitro. (C) 2020 Elsevier B.V. All rights reserved.