Effect of bread making process on bioactive molecules in durum wheat bread and assessment of antioxidant properties by Caco-2 cell culture model

Effects of grain milling and bread making process on some bioactive components naturally present in three durum wheat bread samples and the study of the potential antioxidant properties of phenolic compounds by the human intestinal epithelial cell line Caco-2 were considered in this study. Lutein, the main carotenoid in these matrices, decreased from grain to bread from 50% to 70% depending on the variety while zeaxanthin and beta-carotene content was quite negligible both in grain and in bread samples. Semolina generally showed the lowest extractable phenolic compounds (1280.5-1914.6 mg/kg d.m.) either respect to grain (1445.3-1923.0 mg/kg d.m.) or to bread samples (1537.4-1759.0 mg/kg d.m.). Non-extractable phenolic compounds which resulted strongly reduced in semolina, increased in bread respect to semolina (about 50%) due to the modification induced on the food matrix and, probably, to the Maillard reaction, which takes place during baking. No cellular damage was observed up to a dose of 10.0 mu g/mL of polyphenolic extract. The same amount resulted able to protect the cell from the damage produced by the oxidant agent AAPH. These results underline that the potential health benefits of these compounds are dose-dependent and this aspect must be always taken into consideration.