In vivo breakdown of dietary [methyl−14C] and [uronate-6−14C]pectin-labelled spinach cell walls by rat intestinal microorganisms and incorporation of 14C into host tissues

The metabolism of dietary plant cell wall (PCW) pectin was followed in the rat using PCW isolated from spinach cell cultures C-14-labelled in the galacturonic acid residues or pectic methyl ester groups. C-14-PCW were rapidly broken down in the caecum and colon of the rat and generated several groups of soluble products. [C-14]Methanol was released from [methyl-C-14]pectin-labelled PCW and some of the methanol was converted to C-14-labelled volatile acids. C-14-Labelled volatile acids were also generated from [uronate-6-C-14]pectin-labelled PCW along with soluble but non-volatile material. C-14 derived from both cell wall types was taken up by the caecal and colonic mucosa and transported to the liver, pelt and other body tissues. Some C-14 was excreted as (CO2)-C-14 and in urine.