Thermal and microstructure insights into the mechanism of coating/agglomeration/microencapsulation to preserve the antioxidant potential of Spirulina powder (Arthrospira maxima) by fluidized bed processing

The increase in the consumption of Spirulina as a functional food is due to its recognition as a microalga with numerous health benefits ascribed to its high content of antioxidant compounds. It is essential to shield Spirulina powder from oxidation and undesirable reactions that may compromise its biological activity and the quality of the final product, potentially affecting its shelf-life negatively. Microencapsulation stands out as one of the most effective methods to protect bioactive compounds. Fluidized bed processing, as a microencapsulation technique, was used in the present study and demonstrated that it was favorable to retain the antioxidant properties of Spirulina powder. Thermal, microscopy, and reconstitution analyses reported that: 1) the high stability and protection of the Spirulina powder properties were related to microcapsule physicochemical and microstructural attributes, when different biopolymers were used as wall materials; 2) although protection against oxidation was a general trend, maltodextrin DE-10 showed the maximum thermal protection in the temperature interval of 20-150 °C. Accordingly, a coating/agglomeration/microencapsulation mechanism was derived on the formation of the microcapsules obtained under the processing conditions studied.