Spirulina LEB -18 and Chlorella pyrenoidosa nanoencapsulated through reversed-phase evaporation

Abstract

Cyanobacteria are important in the food industry for producing antioxidant compounds. Algae are a key source of natural antioxidants, primarily due to their ability to scavenge free radicals, which depends on the compound's structure. This study aimed to characterize and evaluate the antioxidant activity of phenolic extracts of Spirulina LEB-18 and Chlorella pyrenoidosa, both nanoencapsulated by reverse phase evaporation. The extraction and quantification of the total phenolic extracts were performed, soon after the lyophilization and encapsulation by reversed-phase evaporation occurred, after which the encapsulation efficiency, size, zeta potential, microscopy, and antioxidant activity of the extracts were evaluated about the capture of free radical DPPH and ABTS. The results showed that Spirulina phenolic extracts obtained a higher content of phenolic extracts (gallic acid 2.55mg. g ^-1 microalgae) than Chlorella extract (1.23 mg. g ^-1 microalgae). Liposomal extracts containing Chlorella phenols demonstrated superior encapsulation efficiency, reaching 72.00 %. In addition, liposomes containing the phenolic extract of Chlorella had a significantly larger mean size, measuring 339.6 nm (p ≤ 0.05). The zeta potential found for the encapsulated samples of liposomes containing the phenolic extract of Chlorella and the phenolic extract of Spirulina were -15.95 and -9.94 mV, both showing good colloidal stability in suspension. Therefore, extracts that maintained a higher antioxidant activity were encapsulated.