Fructan content of commonly consumed wheat, rye and gluten-free breads KEVIN WHELAN 1 , OLIVIA ABRAHMSOHN 1 , GONDI J. P. DAVID 1 , HEIDI STAUDACHER 1 , PETER IRVING 1,2 , MIRANDA C. E. LOMER 1,2 , & PETER R. ELLIS 1 1 King’s College London, Diabetes and Nutritional Sciences Division, London, UK, and 2 Guy’s and St Thomas’ NHS Foundation Trust, Department of Gastroenterology, London, UK Abstract Fructans are non-digestible carbohydrates with various nutritional properties including effects on microbial metabolism, mineral absorption and satiety. They are present in a range of plant foods, with wheat being an important source. The aim of the present study was to measure the fructan content of a range of wheat, rye and gluten-free breads consumed in the United Kingdom. Fructans were measured in a range of breads using selective enzymic hydrolysis and spectrophotometry based on the AOAC 999.03 method. The breads generally contained low quantities of fructan (0.61 – 1.94 g/100 g), with rye bread being the richest source (1.94 g/100 g). Surprisingly, gluten-free bread contained similar quantities of fructan (1.00 g/100 g) as other breads. There was wide variation in fructan content between individual brands of granary (0.76 –1.09 g/100 g) and gluten-free breads (0.36 – 1.79 g/100 g). Although they contain only low quantities of fructan, the widespread consumption of bread may make a significant contribution to fructan intakes. Keywords: Fructan, prebiotic, bread Introduction Fructans are carbohydrates comprising fructosyl monomers with varying degrees of polymerization, some of which have a terminal D-glucose unit. Fructans are classified based upon variations in their degree of polymerization and the bonding between the monomers, with the major group being the inulin-type fructans with b-(2 ! 1) fructosyl-fructose linkages (Roberfroid et al. 2010). There has been much interest in the nutritional properties of fructans and, in particular, the inulin-type fructans. For example, they have prebiotic effects, defined as the selective stimulation of growth and/or activity of one or a limited number of micro-organisms in the gut microbiota that confers health benefits to the host (Roberfroid et al. 2010). Dietary supplementation studies have shown that fructans increase gastrointes- tinal bifidobacteria (Meyer and Stasse-Wolthuis 2009) and mineral absorption (Scholz-Ahrens et al. 2007), and reduce appetite (Cani et al. 2009). However, high intakes (e.g. up to 20g/day) can cause symptoms of bloating and flatulence that are mild in healthy subjects (Bruhwyler et al. 2009) or severe in those with irritable bowel syndrome (Shepherd et al. 2008). Many plants contain fructans and they are therefore consumed in the diets of most people throughout the world. Studies report average dietary intakes to be 4.0 g/day in the United Kingdom (Dunn et al. 2011) and 2.6 g/day in the United States (Moshfegh et al. 1999). Foods such as chicory root, Jerusalem artichoke and garlic are rich sources of fructans (15 – 20, 16 – 20 and 10 – 16 g/100 g, respectively) (Van Loo et al. 1995); however, these are consumed in relatively low quantities and therefore contribute very little to dietary intake (Moshfegh et al. 1999; Dunn et al. 2011). In contrast, although wheat is compara- tively low in fructans (1–4 g/100 g) (Van Loo et al. 1995), its use as a dietary staple means that it is the major contributor to fructan intakes in the United ISSN 0963-7486 print/ISSN 1465-3478 online q 2011 Informa UK, Ltd. DOI: 10.3109/09637486.2011.553588 Correspondence: Dr Kevin Whelan, King’s College London, School of Medicine, Diabetes and Nutritional Sciences Division, 150 Stamford Street, London SE1 9NH, UK, Tel: 44 20 78 48 38 58. Fax: 44 20 78 48 41 85. E-mail: kevin.whelan@kcl.ac.uk International Journal of Food Sciences and Nutrition, August 2011; 62(5): 498–503 Int J Food Sci Nutr Downloaded from informahealthcare.com by King's College London on 05/10/12 For personal use only.