Phenolic acids and antioxidant activity of wild, feral and domesticated diploid wheats

The aims of this research were: a) to analyse the phenolic acid composition and the total polyphenol content of several wild, feral and domesticated Triticum accessions; b) to determine their antioxidant activity by means of diverse spectrophotometric assays (DPPH, FRAP, ABTS and DMPD); and c) to evaluate the effect of different solvents on bioactive compounds extraction and antioxidant assessment. Conjugated and bound phenolic acids were determined by HPLC, while total polyphenol content and antioxidant activity were assessed spectrophotometrically on the extracts obtained with different solvents from whole meal flours. The wild wheats showed the highest phenolic acids, total polyphenol content and antioxidant activity. Among the antioxidant activity assessment methods tested, DPPH, FRAP and ABTS provided similar discrimination of the samples, while DMPD gave different outcomes. The use of several extraction solvents allowed a better characterisation of the antioxidant activity: acidified methanol and water saturated butanol are the most effective solvents for hydrophilic (phenolic acids and anthocyanins) and hydrophilic as well as lipophilic (carotenoids and tocols) antioxidants, respectively.