Evaluación de la actividad antimicrobiana y antioxidante de antocianinas microencapsuladas de maíz morado (Zea mays L.), papa morada (Solanum Tuberosum L.) y mortiño (Vaccinium floribundum Kunth)

Abstract

In the last years, several studies have described the biological activity of various plant secondary metabolites including one of particular interest: anthocyanins. Besides to their pharmacological and therapeutic properties, anthocyanins are used as food dyes and have great potential for obtaining products with added value for human consumption. The aim of the present study was to evaluate the antimicrobial and antioxidant activities of microencapsulated anthocyanins isolated from three Andean plants: purple corn (Zea mays indurata), purple potato (Solanum tuberosum), and Andean blueberry (Vaccinium floribundum Kunth). Anthocyanins were extracted using acidified ethanol and microencapsulated into maltodextrin particles using spray drying. All biological activity assays were performed in triplicate. The antioxidant capacity was evaluated by the DPPH method, which is based on the stability of the 1,1-diphenyl-2-picrylhydrazyl radical. The anthocyanins extracted from the Andean blueberry showed the greatest antioxidant effect. On the other hand, the evaluation of the antimicrobial activity of the extracts was carried out by disc diffusion method, comparing the antimicrobial activity of each extract, with a positive control (the antibiotic gentamicin) and a negative control (sterile water). Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, Bacillus cereus and Staphylococcus aureus were used as indicators. From these tests, it was determined that the anthocyanins extracted from the purple potato presented the highest antimicrobial activity against the indicator bacteria.