Properties of cassava starch¯dicarboxylic acid complexes

Xyloglucan extracted with 4 M KOH from enzymically-depectinated and non-depectinated apple pomace was shown to be fucogalactoxyloglucan. The xyloglucan from the enzymicallydepectinated apple pomace was found to be of lower molecular weight than that from the non-depectinated pomace. Xyloglucan from the non-depectinated pomace had an intrinsic viscosity of 244 ml/g. The oligosaccharides XXFG and XLFG were isolated from the 1,4beta-D-glucanase hydrolysate of the xyloglucan and their 13C NMR spectra were obtained for the first time. Assignment of the anomeric 13C NMR signals of these oligosaccharides permitted the unambiguous assignment of the anomeric region of the 13C NMR spectra of the fucogalactoxyloglucan. In the spectra of the oligosaccharides, splitting was observed in the C6 signal from the fucosyl residues, indicating their proximity to the reducing glucosyl residues and thus yielding information about the conformation of xyloglucan in solution. Integration of the anomeric signals of 1H NMR spectra permits the rapid and non-destructive screening of the composition of xyloglucans from different plants.