Assessment of the antioxidant properties of corn foodstuffs

Resumen del póster presentado a la XVI Conference EuroFoodChem: "Translating food chemistry into health benefits" celebrada en Gdansk (Polonia) del 6 al 8 de julio de 2011.

Cereals including corn or also called maize (Zea mays) foodstuffs are relevant dietary component worldwide. Corn contains many powerful phytonutrients whose activity has gone unrecognized because research methods have overlooked them. Phytochemicals may interact with fibre or proteins and they can be released during digestion process. A new approach named by its authors as GAR (Global Antioxidant Response) based on the combination of in vitro digestion and the QUENCHER approach, which allow to determine the overall antioxidant capacity avoiding any extraction or hydrolysis procedure, has been reported. GAR procedure provides both information regarding to the bioavailability of the antioxidants and the overall antioxidant capacity of samples. The present research aimed to gain insight on the antioxidants of cornmeal and corn fibre. Flours from white, yellow and blue corn and a corn starch based product were analyzed. Solid samples were measured by GAR procedure and the free antioxidants composing them were extracted and their content determined by conventional ABTS method. All the samples showed antioxidant power against ABTS radicals. In all cases, the contribution of the free extractable antioxidants was lower than that found for the in vitro gastrointestinal digests and about 20 fold lower that that determined by QUENCHER approach corresponding to the overall antioxidant capacity of the samples. The soluble antioxidants resulted less effective against ABTS radicals than the insoluble ones derived from the digestion process. The level of bioavailability of free antioxidants after the digestion process was higher than that free extractable under the conditions here assayed. Antioxidant values obtained for gastric and gastrointestinal digests differed. Corn starch presented the lowest antioxidant power among the food samples under study. Results suggested that yellow and blue cornmeals are healthier food options than the rest of the samples and pinpoint the importance of the digestion process on food antioxidant bioavailability.

This research was supported by NATURAGE (AGL2010–17779) and ALIBIRD-CM-S0505/AGR-0153 projects.

Peer Reviewed