The chemical characteristics of apple pectin influence its fermentability in vitro

The aim of the present study was to characterize the fermentability of different apple pectins, as soluble dietary fibres, in vitro. High- and low-methoxyl pectins were fermented completely and very fast by human colonic bacteria, whereas pectic acid and amidated pectin were degraded more slowly. The main fermentation metabolites, i.e. short-chain fatty acids (SCFA) and gases, were produced in lower amounts from pectic acid and amidated pectin. Based on the higher production of SCFA, pectins with a higher degree of methoxylation might be the best candidates for food enrichment due to a beneficial effect on colonic health. On the other hand, the longer persistence of the slowly degraded pectins in the gut may be of advantage as binding and diluting agents for carcinogens.