The impact of processing on the phenolic acids, free betaine and choline in Triticum spp. L. whole grains and milling by-products.

Wheat (Triticum spp. L.) is an important source of nutrients and bioactive compounds with recognized beneficial effects. Wheat undergoes several processes with the final aim of separating the endosperm from the outer layers, usually discarded. In this study, free and bound phenolic acids (PAs) profile, betaine and choline contents were quantified in six different wheat species (durum and bread wheat, turanicum wheat, einkorn, emmer and spelt), the corresponding milling by-products (bran, middlings, aleurone and I, II and III steps of debranning) and flour/semolina, using UHPLC-MS/MS methods. The bound form of phenolics was the component present in higher concentration (80% of the total, in average) and ferulic acid was the most abundant compounds, representing between 67 and 73 % of total PAs. Among the species, bread wheat grain totalized the highest content of total PAs (1209.31 ± 7.3 µg g-1 d.w.). Betaine and choline are abundantly present in wheat species. In general, the highest content of bioactive compounds was found in bran (3 times higher than whole grains), emphasizing the good nutritional profile of these by-products. The milling process leads to a severe reduction of phenolic acids and methyl-donors in the end-products.