On the fate of ingested pectin

Werch, S. C.; Ivy, A. C.

doi:10.1007/bf02998207

Cited by 50 publications

(6 citation statements)

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“…These experiments showed the usefulness of in vitro studies and supported the observations of others that pectic substrates are extensively degraded during their passage through the large intestine (Werch and Ivy 1941;Cummings et a1 1979;Gramstorff Fetzer et al 1979). The almost complete degradation of the apple cell wall showed that the cellulose was readily degradable, and Ehle et a1 (1982) found a similar result for cabbage cellulose.…”

Section: Discussionsupporting

confidence: 80%

Degradation of cell wall material of apple and wheat bran by human faecal bacteria in vitro

et al. 1988

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A B S T R A C TThe effect of the structures of plant cell walls and their component polymers on the degradability of dietary fibre by bacteria of the human colon was investigated by inoculating culture media containing cell wall materials of apple and wheat bran with slurries of human faeces which were then incubated for periods of up to 72 h. In the apple substrates the amounts of pectic polysaccharides were extensively depleted afer 12 h, and afer 24 h over 90% of the initial carbohydrate had been degraded. Material which remained afer incubation was probably comprised of highly branched fragments of rhamnogalacturonans, cross-linked by phenolics and proteins, highly branched fragments of cross-linked xyloglucans, and degraded cellulose. In wheat bran the aleurone layer was preferentially degraded, but the glucuronoarabinoxylans, which were cross-linked by phenolic groups, and the lignified outer layers of the bran were very resistant to attack. Bacteria adhered mainly to the broken or damaged surfaces of the plant cell walls, and in the more resistant tissues only penetrated the intercellular regions.

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Section: Discussionsupporting

confidence: 80%

Degradation of cell wall material of apple and wheat bran by human faecal bacteria in vitro

et al. 1988

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“…In addition t o the hydrolysis of ester groups, the artificial body fluids also caused limited solubilisation of plant cell wall polymers. This would have the effect of facilitating the subsequent hydrolysis of glycosidic bonds of the polysaccharides, which is brought about by the microorganisms of the large intestine (Werch and Ivy 1941;Kelleher et a1 1984;Nyman et a1 1986;Tomlin et al 1986;Englyst et a1 1987;Gray et a1 1993a, b;Buchanan et a1 1994a, b).…”

Section: Discussionmentioning

confidence: 99%

The solubilisation and hydrolysis of spinach cell wall polysaccharides in gastric and pancreatic fluids

et al. 1995

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Abstract:The aim of this work was to investigate the fate, in the upper gut of a monogastric animal, of polymers bound within plant cell walls. Uniformly and specifically 14C-labelled spinach cell walls were incubated in artificial body fluids with and without pepsin or pancreatin. In the absence of enzymes, artificial pancreatic juice (pH 8.8) at 37°C hydrolysed the methyl ester groups of wall-bound pectins [half-life (t1,2) 25 h]; the O-acetyl ester groups of cell wall polysaccharides were much more stable (tliz 84 h). In contrast, artificial gastric juice (pH 1.85) hydrolysed wall-bound acetyl groups more rapidly (t,,2 -24 h) than methyl ester groups ( t , / 2 -350 h). Thus, a proportion of the methyl and acetyl groups of plant cell wall polymers will be released in the upper gut as methanol and acetic acid, raising the question of whether these groups should be included within the definition of dietary fibre. The artificial body fluids also caused limited solubilisation of wall polymers but no hydrolysis to mono-or oligosaccharides. Neither pepsin nor pancreatin promoted the hydrolysis of methyl ester or acetyl groups. The small amounts of [14C]protein present in the cell wall preparations were hydrolysed by pepsin or pancreatin to yield amino acids and oligopeptides; however, the major polysaccharides of spinach cell walls were neither degraded to low-molecular-weight products nor solubilised by these enzymes.

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“…Using less precise methods Werch & Ivy (1941) made a similar observation in man. From in vitro fermentation studies (Werch et al 1942) and studies of ileostomists (Werch & Ivy, 1941) they suggested colonic fermentation of pectin was occurring. It is also evident from the amount of faecal polysaccharide excreted that a large proportion (approximately 85 %) of the fibre in the control diet was also metabolized during passage through the gut.…”

Section: Discussionmentioning

confidence: 99%

The digestion of pectin in the human gut and its effect on calcium absorption and large bowel function

et al. 1979

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I . The effect of dietary fibre digestion in the human gut on its ability to alter bowel habit and impair mineral absorption has been investigated using the technique of metabolic balance.2 . Five healthy male students were studied for 9 weeks under controlled dietary conditions and during the last 6 weeks they took 36g pectin/d. Bowel habit, transit through the gut, faecal fibre excretion, calcium balance and faecal composition were measured. 3.During the control period only 15 % of the dietary fibre ingested was excreted in the stools and when pectin was added to the diet there was no increase in fibre excretion. Stool frequency and mean transit time were unchanged by pectin but stool wet weight increased by 33 % and faecal excretion increased (%) for fatty acids 80, nitrogen 47, total dry matter 28 and bile acids 35. Ca balance remained unchanged.4. It may be concluded from these results that dietary fibre is largely metabolized in the human gut and dietary pectin completely so. This could explain its lack of effect on bowel habit and Ca balance. Other changes in the faeces may be related to an increase in bacterial mass.

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On the fate of ingested pectin

Cited by 50 publications

References 6 publications

Degradation of cell wall material of apple and wheat bran by human faecal bacteria in vitro

Degradation of cell wall material of apple and wheat bran by human faecal bacteria in vitro

The solubilisation and hydrolysis of spinach cell wall polysaccharides in gastric and pancreatic fluids

The digestion of pectin in the human gut and its effect on calcium absorption and large bowel function

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