Variations of the content of phenolic acids in durum wheat as a function of genotype and environment

Increasing evidence from clinical and epidemiological studies suggests that the regular consumption of whole grain and whole-grain derivatives might reduce the risk of developing chronic illnesses such as cardiovascular diseases, type-2 diabetes, and certain types of cancer. These health benefits have been partly attributed to the occurrence in wheat, as well as in other cereals of phytochemicals with antioxidant activity, which include phenolic acids (PAs) belonging to hydroxycinnamic acids and hydroxybenzoic acids derivatives, such as ferulic, p-coumaric, p-hydroxibenzoic, vanillic and siringic acids. The content of these compounds may have a wide range of variability and their occurrence has been related to the health-promoting effects of whole grains as regards the antioxidant activity. In addition, with the increasing popularity of functional foods, it is crucial to understand the distribution of phenolic compounds in different milling extractions which may have important implications in ensuring their health benefits. We report the results of a study carried out to evaluate the impact of growing environmental and different genotypes of durum wheat, cultivated in different regions, on the total antioxidant capacity (TAC) and on the occurrence and content of phenolic acids as soluble free, soluble conjugated and insoluble bound acids. The phenolic acids (free, conjugated and bound forms) were extracted following a method developed by Li et al with some modifications and determined by a RP-HPLC method developed in our laboratory. TAC levels were determined following the direct method described by Serpen et al using ABTS radical and expressing data as millimol Trolox equivalent antioxidant capacity per kg (mmol TEAC/kg).