The Effect of Pre-treatment of Bran on the Bioavailability of Ferulic Acid and Other Bioactive Compounds From Wholegrain Breads Enriched in Bran

Rationale: Whole grain consumption has been associated with a lower risk of developing metabolic syndrome, cardiovascular disease, type 2 diabetes and some type of cancers. Whole grain is a good source of antioxidant compounds such as ferulic acid, which has been considered its major antioxidant. Ferulic acid is also the major phenolic compound in wheat grain, it is mainly located in the bran, more precisely in the cell walls of the aleurone layer and overall bran layers. Most of the ferulic acid is covalently bound to the indigestible cell wall polysaccharides, which limits the bioavailability of ferulic acid from cereal products to the merely form of free ferulic acid.

Processing possibilities in the development of cereal products might be used to optimize the bioavailability of ferulic acid in humans and the possible health effect of the wholegrain product.

An innovative processing in bread making has been developed. The processing consisted of pretreatments of the bran with an enzymatic mixture and yeast fermentation before its incorporation into the dough. The impact on the in vitro assessed bioavailability of ferulic acid was a 5-fold increase over the normal bran enriched wholegrain bread in a gastrointestinal model. Therefore in our study we will compare the kinetics and total bioavailability of ferulic acid from wholegrain breads enriched in native or pretreated bran. Furthermore, the colonic metabolism of ferulic acid and overall major colonic metabolites such as short chain fatty acids (SCFA) will be studied. Finally, total antioxidant capacity and ex vivo inflammatory responses will be investigated in order to determine the effect of the pretreatment of on the immunomodulatory properties of bran.

Objective: The aim of the present study is to investigate the effect of pretreatment of bran on improving the bioavailability of ferulic acid. As secondary endpoints we will investigate the changes in plasmatic antioxidant capacity, anti-inflammatory effects, colonic metabolites from ferulic acid and short chain fatty acids (SCFA).

Study design: Blind, cross-over, randomised design. Wash-out period of one week. Three days of low antioxidant diet. Standardised meal low in phenolic and antioxidant compounds will be consumed the evening before the trial.