Determination of antioxidants in edible grain derivatives from the Canary Islands by capillary electrophoresis

A preliminary study of the antioxidant content of hand-produced grain derivatives from the Canary Islands, named gofio, is developed by means of a capillary electrophoresis (CE) method. Protocatechuic acid, salicylic acid, p-hydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, ferulic acid and sinapic acid were extracted from corn, wheat, barley and pea gofio samples by sonication with methanol and were successfully separated by CE using a polycation, hexadimetrine bromide (HDB), as electrosmotic flow modifier. The separation was achieved using a running buffer consisting of 125 mM boric acid, 49 mM disodium hydrogen phosphate, 0.002% (w/v) HDB and 2.5 mM α-cyclodextrin at pH 7.5. The developed procedure allowed the simultaneous determination of the selected antioxidants in less than 3.5 min. The electrophoretic profile obtained for each kind of flour (corn, wheat, barley and pea) allowed differentiation of the type of gofio. Among the analyzed samples, corn gofio showed the highest antioxidant content. Furthermore, highly roasted corn or wheat gofio samples were also analyzed and their antioxidant contents were lower than those of less roasted samples.