An alcohol-insoluble residue from carrot root, analysed by an establis
hed method, appeared to contain partially non-methyl esterified pectic
polysaccharides. Digestion with Driselase, to which such esters are t
hought to be resistant, gave small amounts of acidic oligosaccharides.
Treatment with alkali at room temperature hydrolysed some of these co
mponents and gave more acidic 1,4-linked oligogalacturonic acids as pr
oducts. Since Driselase is known to cleave pectic methyl esters, these
components appeared to contain non-methyl galacturonoyl esters. Howev
er, the predominant component of this type was shown to be a monomethy
l esterified, singly-acetylated tetragalacturonic acid. It was convert
ed to galacturonic acid when re-treated with Driselase and, thus, was
a product of incomplete digestion. Other, more minor components with s
imilar properties were either other methyl esterified oligomers or wer
e present in such small amounts that their characterization was not po
ssible. (C) 1998 Elsevier Science Ltd. All rights reserved.