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

Underexploited sources of bio-based wall materials for bioactive compounds (such as -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 -carotene was evaluated. Microcapsules were produced by spray-drying and their morphological and physicochemical characterization was carried out. The microcapsules presented a spherical shape (particle size distribution: 0.3 - 30 m) and encapsulation efficiencies ranging from 64 to 69%. Results showed that protein-based microcapsules had better -carotene storage stability as compared to starch-based microcapsules (at 8 and 25 ºC). -carotene release kinetics at 37 ºC and pH 7.4 could be mainly described by structural-relaxation phenomenon using the linear superposition model. Moreover, encapsulated -carotene exhibited higher bioaccessibility than its free form after simulated in vitro digestion tests. Microcapsules did not affect cell viability at 0.0625mg·L-1 of -carotene. Thus, amaranth grain biopolymers-based microcapsules were successfully developed as promising -carotene delivery systems to be added to food products and consequently, to improve their functionality.The authors acknowledge CNPQ-Brazil for IF/00300/2015 fellowship and Foundation for Science and Technology (FCT) for SFRH/BPD/104712/2014 fellowship. This work was supported by: FCT/MCTES under the scope of UID/CTM/50011/2019; FCT under the scope of the strategic funding of UIDB/04469/2020 unit and; LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems (LA/P/0029/2020). Also, this work is funded by NORTE2020 Funds through the Support System for Scientific and Technological Research - "Structured R & D & I Projects" - Horizon Europe under the project NORTE-01-0145-FEDER-000070.