Complex Coacervates Formed between Whey Protein Isolate and Carboxymethylcellulose for Encapsulation of β-Carotene from Sacha Inchi Oil: Stability, In Vitro Digestion and Release Kinetics

The present work aimed to study the influence of the pH and protein ratio on the formation of complex coacervates of carboxymethylcellulose (CMC) and whey protein isolated nanoparticles (WPIN). These biopolymers and transglutaminase, as a cross-linking agent, were used to encapsulate sacha inchi oil (SIO) containing beta-carotene (beta-C). The stability of beta-C from SIO microcapsules (beta-SIO microcapsules) was evaluated under in vitro digestion using an INFOGEST 2.0 in vitro digestion protocol. The release of beta-C in a simulated food model was studied, and mathematical models were used to determine the mechanism. A ratio of 1:6 (CMC/WPIN) at pH 3.5 was used for the formation of the complex. Chemical and morphological analyses suggested that SIO was microencapsulated and that a high encapsulation efficiency was obtained. The beta-C from beta-SIO microcapsules was preserved in vegetable oil (food model), and Fickian diffusion occurred. The beta-C from beta-SIO microcapsules was preserved under oral and gastric conditions, and higher release occurred during intestinal digestion when samples were subjected to in vitro digestion simulation. After in vitro digestion, the beta-C from beta-SIO microcapsules presented higher stability (83.37%) and acceptable bioaccessibility (31.16%). There are few studies in the literature of encapsulated SIO using the CMC/WPIN complex or studies of the release of beta-carotene from SIO during in vitro digestion and in food simulants. The knowledge obtained in this study will facilitate the use and applications of beta-C-loaded microcapsule delivery systems.