A. Oosterveld et al., Isolation of feruloylated arabinans and rhamnogalacturonans from sugar beet pulp and their gel forming ability by oxidative cross-linking, CARBOHY POL, 44(1), 2001, pp. 9-17
Rhamnogalacturonans and arabinans were purified from an autoclave extract o
f sugar beet pulp by size-exclusion and anion-exchange chromatography. Trea
tment with polygalacturonase and pectin methyl esterase was used to improve
chromatographic separation of the rhamnogalacturonans from the homogalactu
ronans. Four populations were obtained: two rhamnogalacturonan populations
with a high arabinose and ferulic acid content and with apparent molecular
weights of 930 and 130 kDa, respectively, a feruloylated arabinan populatio
n and a (digested) homogalacturonan population with apparent molecular weig
hts of 18 and 6 kDa, respectively.
Cross-linking of the high molecular weight rhamnogalacturonans with hydroge
n peroxide and peroxidase gave an increase in viscosity and led to gel form
ation at concentrations <1.0%. The second rhamnogalacturonan population for
med gels at concentrations as low as 0.75%. Cross-linking of the arabinan r
esulted in gel formation at a concentration of 4.0%. The properties of the
gels are discussed in terms of the storage modulus (G') and tan <delta>. (C
) 2000 Elsevier Science Ltd. All rights reserved.