Phenolic acids composition, total polyphenols content and antioxidant activity of Triticum monococcum, Triticum turgidum and Triticum aestivum : a two-years evaluation

Wheat is a good source of polyphenols, plant metabolytes with beneficial effects on human health. However, little information is available on phenolic acid composition and concentration in different Triticum species, as well as on possible environmental effects. To shed some light on this issue, thirtynine wheat accessions cropped for two years and belonging to different Triticum species (Triticum monococcum, Triticum turgidum ssp. dicoccum, turanicum and durum, Triticum aestivum ssp. spelta and aestivum) were assessed for phenolic acids (ferulic, p-coumaric, vanillic, syringic, p-hydroxybenzoic, caffeic acids and syringaldehyde), total polyphenols and antioxidant activity in soluble conjugated and insoluble bound extracts. Ferulic acid was the most abundant compound in both extracts. Insoluble bound phenolic acids represented >90% of total phenolic acids. Einkorn showed the maximum concentration of conjugated phenolic acids (50.5 mg/kg DM), while durum and bread wheats presented the highest content of bound phenolic acids (651.8 and 629.2 mg/kg DM, respectively). Cropping year influenced the concentration of conjugated but not of bound phenolic acids. A survey of phenolic acid distribution in the kernel showed that they are rare in endosperm, but abundant in germ and bran. Total polyphenols and antioxidant activity were highly correlated to phenolic acid content.