Antioxidant Potential Profile of Portuguese Wheat (Bread and Durum) Germplasm

Antioxidant properties of phenolic compounds are presumed responsible for several health benefits due to their capacity to scavenge free radicals and chelate metals prevenient oxidative stress. Since these compounds are ubiquitous in plants, including cereals, the available antioxidant potential profile of wheat genotypes could allow the development of new cultivars with an increased nutritional value that may result in antioxidant-rich foods. In this study, total phenolics content (TPC) was quantified in the whole grain flour of 92 wheat (46 genotypes each from bread and durum) genotypes, which were evaluated under field conditions during 2 different crop seasons (2004-05 and 2009-10). Of the ninety-two, fourteen (six and eight from bread and durum wheat, respectively) genotypes were comprehensively evaluated for antioxidant activity [2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and reducing power] and ferulic acid contents. The results revealed that substantial genotypic variability exists for TPC in wheat genotypes with a mean value of 991 and 787 µg ferulic acid equivalents (FAE)/g DW in bread and durum wheat, respectively. Moreover, bound phenolics as a source of ferulic acid, including both cis- and trans-isomers, were observed as a major contributor to the total phenolics, which must be considered in assessing the antioxidant activity in wheat grain. In conclusion, these findings may also help improve wheat grains as natural sources of antioxidants utilizing selected genotypes in breeding programs.