Evaluación de la capacidad antioxidante y estabilidad de un extracto obtenido a partir de residuos de hojas de la cosecha del maíz (Zea mays)

Abstract

Maize (Zea mays) is a major crop in Ecuador, generating high volumes of underutilized agricultural waste which, if poorly managed, could pollute the environment or have non-economic value. Maize leaves, rich in biomolecules such as chlorophyll and flavonoids, hold potential for industrial applications in food and cosmetics. This research aims to evaluate the antioxidant capacity and stability of maize leaf extracts to promote their utilization. Two extracts were prepared using 96 percent ethanol and an acetone-ethanol mixture in a 3 to 1 ratio, which were analyzed through FTIR spectrophotometry. Their antioxidant capacity was studied using the DPPH assay. The extracts were stored at different temperatures for four weeks, and their FTIR spectra and antioxidant capacity were examined. The FTIR study indicates the presence of hydroxylated compounds in both extracts, acetone extract containing more diverse groups. The antioxidant capacity was 107.15 and 104.39 micromoles of Trolox per gram of maize leaves for ethanol and acetone-ethanol extracts, respectively. The stability study showed changes in the FTIR spectra of both extracts, with an increase in the presence of new functional groups. The acetone-ethanol extract exhibited greater stability in antioxidant capacity, whereas the ethanol extract showed a significant reduction. Refrigeration proved to be the best condition for preserving antioxidant activity in both extracts.