British Journal of Nutrition

Research Article

Short-chain fatty acids produced in vitro from fibre residues obtained from mixed diets containing different breads and in human faeces during the ingestion of the diets

Elisabeth Wiskera2 c1, Martina Daniela2, Gerhard Ravea3 and Walter Feldheima2

a1 Christian Albrechts-University of Kiel

a2 Institute of Human Nutrition and Food Science, Düsternbrooker Weg 17, D-24105 Kiel, Germany

a3 Variationsstatistik, Hermann-Rodewaldstraβe 9, D-24098 Kiel, Germany

Abstract

It was studied whether the type of bread (i.e. a low-fibre wheat–rye mixed bread and coarse or fine wholemeal rye bread) either as part of a diet or alone, had an influence on the short-chain fatty acids (SCFA) produced during in vitro fermentation. Fermentation substrates were dietary fibre residues obtained from diets and breads. In addition, it was investigated whether the faecal SCFA pattern in the inoculum donors, who ingested the experimental diets, could be predicted by in vitro fermentation. Yields of SCFA in vitro were 0·51–0·62 g/g fermented polysaccharide. In vitro, the molar ratios of butyrate were higher for the two high-fibre diets containing coarse or fine wholemeal bread than for the low fibre diet containing wheat–rye mixed bread; the difference was significant for the coarse (P < 0·01), but not for the fine bread diet (P = 0·0678). The coarse wholemeal bread alone produced a higher molar ratio of butyrate than the fine wholemeal bread (P < 0·05) and the wheat–rye mixed bread (P < 0·01). Ingestion by the inoculum donors of the diets containing wholemeal bread led to higher faecal butyrate ratios (molar ratios: coarse bread diet 19·6, fine bread diet 17·7) compared with the wheat–rye mixed bread-containing diet (14·9), but the differences between the diets were not significant. For the diets investigated, there were no significant differences between faecal and in vitro SCFA patterns.

(Received December 18 1998)

(Revised September 07 1999)

(Accepted December 08 1999)

Correspondence:

c1 *Corresponding author: Dr E. Wisker, fax +49 431 880 1528, e-mail ewisker@nutrfoodsc.uni-kiel.de