Crystallinity of lyophilised carrot cell wall components

The aim of this work was to investigate the effect of removal of cell wall components on the crystallinity of cell walls using X-ray diffraction. Vari ous insoluble cell wall residues were prepared following a sequential extra ction of carrot cell wall material. X-ray diffraction patterns were typical of cellulose although there was a possible contribution of pectic polysacc harides to the crystallinity. As more amorphous material was removed to pro duce a cellulose rich residue, the crystallinity index increased from 12 to 16%, larger than that estimated from cellulose alone. For the last residue treated with 4M KOH, a lower value of crystallinity was found (14%) which resulted from the change of some crystalline domains of cellulose into amor phous regions. Pressing conditions (temperature, water content) have been i nvestigated and did not alter the crystallinity index significantly. (C) 19 99 Elsevier Science B.V. All rights reserved.