Effects of microencapsulation on the preservation of thermal stability and antioxidant properties of Spirulina

This study aimed to evaluate the effects of microencapsulation of Spirulina in an alginate matrix on its properties, thermal stability and antioxidant potential for obtaining a product with controlled release at different pHs. For this, dry Spirulina biomass was microencapsulated using the ionic gelation technique in a calcium alginate matrix. The microstructure, thermal properties and chemical interactions between the matrix and the nucleus were characterized. At the same time, the encapsulation efficiency together with the release profile of the antioxidant compounds and the solubility of the microcapsules were evaluated. The results confirm that the microencapsulation of the Spirulina biomass preserved its antioxidant potential under adverse conditions (pH 1.2) and inhibited denaturation at elevated temperatures (100 °C). The encapsulation efficiency of 91.7% showed high retention of Spirulina in the calcium-alginate complex, maintaining the integrity of the microcapsule with solubility below 5%. The 85% release of phycocyanin was achieved under alkaline conditions that simulate gut conditions. These results allow to expand the insertion of the Spirulina biomass in food matrices, preserving its properties.