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

•The milling process leads to a severe reduction of phenolic acids and methyl-donors in the end-products.•Data confirmed that the content of bioactive compounds in bran is significantly higher than other by-products.•Among by-products, emmer bran was found as the highest in PAs.