Effect of bioprocessing of wheat bran in wholemeal wheat breads on the colonic SCFA production in vitro and postprandial plasma concentrations in men Nuria Mateo Anson a,b,⇑ , Robert Havenaar a , Wouter Vaes a , Leon Coulier a , Koen Venema a , Emilia Selinheimo c , Aalt Bast b , Guido R.M.M. Haenen b a TNO Quality of Life, P.O. Box 360, 3700 AJ Zeist, The Netherlands b University of Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands c VTT, Technical Research Centre of Finland, Espoo, FI-02044 VTT, Finland article info Article history: Received 17 September 2009 Received in revised form 7 February 2011 Accepted 8 March 2011 Available online 21 March 2011 Keywords: Wheat bran Bioprocessing Butyrate Fibre abstract The health benefits of whole grain consumption can be partly attributed to the inclusion of the bran or outer-layers of the grain rich in dietary fibre. Fibre is fermented in the colon, leading to the production of beneficial metabolites, such as short-chain fatty acids (SCFA). The effect of five different types of bread on the SCFA production was studied in an in vitro model of human colon. Additionally, the postprandial effects of two selected breads on the SCFA plasma concentrations were investigated in men. A higher in vitro production of butyrate was induced by wholemeal wheat bread with bioprocessed bran than by native bran. The increase in butyrate seemed to be in exchange for propionate, whilst the total SCFA production remained similar. However, differences between the two breads in the postprandial butyrate concentrations could not be detected in peripheral blood of men, probably due to an effective utilisation by colonocytes. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Whole grain consumption has been associated with a reduced risk of type-2 diabetes (de Munter, Hu, Spiegelman, Franz, & van Dam, 2007), cardiovascular disease (Jensen et al., 2004) and some types of cancer: colonic cancer (Larsson, Giovannucci, Bergkvist, & Wolk, 2005; Schatzkin et al., 2007), pancreatic cancer (Chan, Wang, & Holly, 2007), and small intestinal cancer (Schatzkin, Park, Leitzmann, Hollenbeck, & Cross, 2008). The health benefits of whole grains versus refined grains may be attributed to the inclu- sion of the outer layers of the grain, the bran. It is in the bran, that most of the micronutrients, phytochemicals and fibre of the grain are located (Hemery, Rouau, Lullien-Pellerin, Barron, & Abecassis, 2007; Mateo Anson, van den Berg, Havenaar, Bast, & Haenen, 2008). Fibre intake is reported to decrease intestinal transit time and increase stool bulk, reduce levels of total and/or LDL cholesterol in blood, and reduce concentrations of postprandial blood glucose and insulin (Anderson et al., 2009). The health benefits of fibre are linked to the formation of metabolic end-products by the colon microbiota, such as the short-chain fatty acids (SCFA). SCFA forma- tion is beneficial for the microbiota that colonise the large intestine to obtain energy for maintenance and multiplication, and for the host to maintain pH and deliver energy to the colonic cells (Macfarlane & Gibson, 1997). Particularly, butyrate is the preferred source of energy for the colonocytes and it has been reported to have antiproliferative activities and to modulate gene expression and immunogenicity (Hamer et al., 2008). The metabolic effects of fibre depend on the physicochemical properties, the degree of polymerisation, the arabinose/xylose ra- tio, the distribution of side chains, the degree of cross-linking, and the extent of digestion in the small intestine (Napolitano et al., 2009). The fibre in wheat bran is mainly composed of the cell wall polysaccharides: arabinoxylan (64%), cellulose (29%), and non cellulosic glucan (6%) (Fincher & Stone, 1986). The structure of these polysaccharides is cross-linked by small phenolic acids, such as ferulic acid. A high degree of cross-linking increases the molecular size of the polysaccharide and reduces its solubility (Izydorczyk & Biliaderis, 1992). It has been shown that processing can increase the bioavailabil- ity of nutrients and other compounds through chemical or enzy- matic reactions that hydrolyse or release them from the food matrix (Mateo Anson et al., 2009; Watzke, 1998). Similarly, biopro- cessing may result in structural modifications of the fibre affecting the fermentation properties in the colon. In the present study, the effect of bran addition to wholemeal wheat bread and the effect of the bran bioprocessing, by fermentation or by hydrolytic enzymes combined with fermentation, on the production of short chain fatty acids (SCFA) are studied in an in vitro model of colon. 0308-8146/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2011.03.043 ⇑ Corresponding author. Address: Department of Pharmacology and Toxicology, University of Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands. Tel.: +31 433881417; fax: +31 433884149. E-mail address: nuria.mateoanson@maastrichtuniversity.nl (N.M. Anson). Food Chemistry 128 (2011) 404–409 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem