Change in B and E vitamin and lutein, β-sitosterol contents in industrial milling fractions and during toasted bread production

Wheat constitutes a major part of the daily diet in Europe and represents an important source of vitamins. Thus, it is important to monitor the levels of vitamins upon the wheat-based foods processing operations, such as production of new wheat milling fractions, bread and breadmaking toasted bread. The variability in B and E vitamin, and Lutein, B-sitosterol contents were measured in semi-coarse wheat flours and milled fractions obtained from industrial milling company, as well as in the toasted breads made from them by means of LC-MS/MS and stable isotope dilution assay. The concentration of nicotinic acid, pyridoxal, pyridoxine, pantothenic acid, beta-gamma-tocopherol were significantly higher in the coarse bran, while an important amount of lipid-soluble bioactive compounds was recovered in the discard sifting. The toasting step induced a significant increase of alpha-tocopherol (+216%), beta-gamma-tocopherol (+52%), alpha-tocotrienol (+83%), beta-gamma-tocotrienol (+32%), nicotinic acid (+55%), nicotinamide (+97%) and of pyridoxine (+77%). Our finding emphasized the need to determine for each bioactive compounds the part which is bioavailable in the interesting part of the bran. In addition, we demonstrated that the toasting process can release bound bioactive compounds and led to enhance the nutritional quality of toasting bread.