Exploring the performance of amaranth grain starch and protein microcapsules as β-carotene carrier systems for food applications

Underexploited sources of bio-based wall materials for bioactive compounds (such as β-carotene) encapsulation have gained increasing interest within the scientific community. In this study, the potential of amaranth (Amaranthus cruentus) grain starch and protein rich fractions as microcapsules’ wall materials to carrier β-carotene was evaluated. Microcapsules were produced by spray-drying and their morphological and physicochemical characterisation was carried out. The microcapsules presented a spherical shape (particle size distribution: 0.3–30 µm) and encapsulation efficiencies ranging from 64 % to 69 %. Results showed that protein-based microcapsules had better β-carotene storage stability as compared to starch-based microcapsules (at 8 and 25 °C). β-carotene release kinetics at 37 °C and pH 7.4 could be mainly described by structural-relaxation phenomenon using the linear superposition model. Moreover, encapsulated β-carotene exhibited higher bioaccessibility than its free form after simulated in vitro digestion tests. Microcapsules did not affect cell viability at 0.0625 mg L⁻¹ of β-carotene. Thus, amaranth grain biopolymers-based microcapsules were successfully developed as promising β-carotene delivery systems to be added to food products and consequently, to improve their functionality.