IN-VIVO BREAKDOWN OF DIETARY [METHYL-C-14] AND [URONATE-6-C-14]PECTIN-LABELED SPINACH CELL-WALLS BY RAT INTESTINAL MICROORGANISMS AND INCORPORATION OF C-14 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.