Influence of structure on in vitro fermentability of commercial pectins and partially hydrolysed pectin preparations

Pectins are of interest for nutritionists as dietary fibres, as they have been shown to exhibit a hypocholesterolemic effect and to be protective against cancer. The aim of the present study was to investigate the physiological behaviour of pectin preparations differing in composition and degree of polymerisation by a well established in vitro fermentation method and to correlate their fermentation pattern to chemical and physical features. The analysed samples exhibited some chemical and physical differences. The in vitro fermentation experiments indicated a very good fermentability for all substrates. Small differences in the degradability by colonic microorganisms were only found depending on the degree of methoxylation. Partially hydrolysed pectins showed a similar behaviour as the corresponding starting materials, therefore higher amounts could be added to foods without causing gelling, and health effects due to colonic fermentation would be enhanced. Further experiments will be carried out to identify other factors influencing the fermentability of pectins.