Ma. Coimbra et al., ISOLATION AND CHARACTERIZATION OF CELL-WALL POLYMERS FROM OLIVE PULP (OLEA-EUROPAEA L), Carbohydrate research, 252, 1994, pp. 245-262
Cell wall material (CWM) was prepared from olive pulp, which is rich i
n oil. Polymers were solubilised from the CWM by sequential extraction
with rans-1,2-cyclohexanediamine-N,N,N',N'-tettraacetic acid, sodium
salt; Na2CO3; 1 M KOH; 4 M KOH; and 4 M KOH+borate to leave the cellul
ose-rich residue (CR). A suspension of this residue, on neutralisation
, released a pectic material, to give residue CR1. The residue CR1 con
tained cross-linked pectic polysaccharides and some cell wall glycopro
teins which were solubilised with chlorite-acetic acid. The polymers f
rom the Various extracts were fractionated by graded precipitation wit
h ethanol prior to anion-exchange chromatography, and selected fractio
ns were subjected to methylation analysis. Closely related pectic poly
saccharides rich in arabinose were the major components of the cell wa
lls and they differed in their ease of extraction from the wall matrix
. Significant amounts of acidic xylans were isolated from the precipit
ates obtained on neutralisation of the 1 M KOH extracts, and a large p
roportion of these would have been derived from the lignified sclereid
s; the xyloglucans from the supernatant fractions had xylans associate
d with them. However, significant amounts of xyloglucans associated wi
th glucomannans, but virtually free of xylans, were isolated from the
'neutral fractions' of the supernatant solutions from the 4 M KOH and
4 M KOH+borate extracts. These 'neutral fractions' also contained sign
ificant amounts of hydroxyproline-rich cell wall glycoproteins. The an
omeric configurations of the sugars in the glucuronoxylans were determ
ined by C-13 NMR spectroscopy. The structural features of the wall pol
ymers are discussed in relation to the structure of the cell wall of t
he fruit pulp.