Bioavailability of ferulic acid is determined by its bioaccessibility

Epidemiological studies have linked whole grain consumption to prevention of several chronic diseases. Whole grain is a source of important phytochemicals, such as ferulic acid (FA). FA is the most abundant phenolic and major contributor to the in vitro antioxidant capacity of wheat grain. Several studies have reported highly variable results on FA bioavailability (0.4-98%). The binding of FA to polysaccharides may limit its bioavailability. Therefore, our study aimed at monitoring release features of FA during gastrointestinal (GI) transit. This was termed bioaccessibility. The bioaccessibility of FA was studied from different wheat fractions and breads with the use of a dynamic in vitro system that simulates the upper GI transit and digestion. The results showed low bioaccessibility of FA from the wheat fractions and breads (<1%). However, the bioaccessibility was high when free FA was added to flour (similar to 60%). The bioaccessibility of FA appeared to be determined by the percentage of free FA. In wheat grain, most of FA is bound to arabinoxylans and other indigestible polysaccharides restricting its release in the small intestine. New processing developments should be considered to increase free FA in the cereal matrix in order to improve its bioavailability and systemic health effect. (C) 2008 Elsevier Ltd. All rights reserved.