Refinement of a protocol for the assessment of antioxidative activities of normal maize (NM) and quality protein maize (QPM)

Abstract

The present investigation was performed to evaluate the effect of extraction methods (reflux and stirring) and solvent concentrations on total phenolics, flavonoids, and antioxidant activity as % inhibition, metal chelating activity, and phosphomolybdenum assay of normal maize (NM) and QPM. These compounds can be water-soluble, insoluble or bound to the cell wall and making extraction difficult. Thus, extraction plays an important role in the quantification of antioxidant activity. Results revealed that the quality protein maize (QPM) extracts possess higher flavonoids and metal chelating activity than NM, prepared using the stirring method. A significant correlation was found between phenolics and antioxidative activity for both varieties and methods. Practical applications Maize, as being an excellent source of bioactive compounds having beneficial effects on human health have great potential to reduce free radicals and protect the body from chronic diseases. Therefore, maize products can also be regarded as functional foods.