Comparative effects of dietary wheat bran and its morphological components (aleurone and pericarp-seed coat) on volatile fatty acid concentrations in the rat

Abstract

1. Adult male rats were fed on diets containing 100 g dietary fibre/kg either as a-cellulose or wheat bran or the pericarp-seed coat or aleurone layers prepared from that bran by sequential milling and air elutriation and electrostatic separation.2. After 10 d, concentrations of total volatile fatty acids (VFA) in caecal fluid were significantly different between groups and fell in the order: aleurone > wheat bran > pericarp-seed coat > cellulose. This ranking probably reflected the ease of fermentation of fibre polysaccharides by colonic bacteria which also resulted in a considerably higher faecal bacterial mass in the aleurone group.3. Because of the differences in the volume ofcaecal digesta, the mass of caecal VFA was considerably the highest in the aleurone group, intermediate with wheat bran and equally low in the pericarp-seed coat and cellulose groups.4. The diet based on aleurone gave a relatively higher proportion of propionate but with both pericarp-seed coat and wheat bran the contribution of butyrate was raised.5. VFA concentrations in hepatic portal venous plasma were proportional to caecal concentrations with very high (> 3 mM) values being recorded in the aleurone group.6. The findings are discussed in relation to the apparent susceptibility of the morphological components of wheat bran to fermentation by large bowel bacteria.

Short-Chain Fatty Acids Protect Against High-Fat Diet–Induced Obesity via a PPARγ-Dependent Switch From Lipogenesis to Fat Oxidation

“…The SCFA concentrations of 3 mmol/L used here represent typical intestinal concentrations rather than portal blood concentrations (43), although even portal SCFA concentrations may exceed 2 mmol/L postprandially after a fiber-rich diet is digested (44)(45)(46). Therefore, we also incubated HepG2 and differentiated 3T3-L1 cells at different concentrations of SCFAs.…”

Digestion of non-starch polysaccharides by non-ruminant omnivores

“…The pattern of VFA found in the LI is readily altered by diet (Cheng et al 1987;Key & Mathers, 1987;Goodlad & Mathers, 1990;Mathers et al 1990), but from the viewpoint of energy salvage it is the proportion of propionate which is most important. For this calculation, two fermentation patterns will be used: type I with molar proportions (mmol/mol) of 650, 200 and 150 for acetate, propionate and butyrate respectively and type I1 where propionate contributes 350 mmoUmol at the expense of acetate (Table 1).…”

Nutritional Composition and .ALPHA.-Glucosidase Inhibitory Activity of Five Chinese Vinegars

“…The concentrations of acetic acid in the vinegars ranged from 5.7% (w/v) to 9.8% (w/v) ( Table 3). According to Cheng et al 7 , when food containing 10-150 mmol/L of acetic acid was eaten, the concentration of acetic acid possibly reached the millimolar level in the small intestine. Such a level can have physiological effects, including disaccharidase and angiotensin-I converting enzyme inhibitory activities in the small intestine 22 .…”