Pectic Polysaccharides of Fruits: Characterization, Fractional Changes and Industrial Application - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 228

backbone containing an equal number of galacturonic acid (1,4-GalA p ) and rhamnose
(sum of 1,2-Rha p and 1,2,4-Rha p )residues (Oechslin et al., 2003). The arabinan-rich
pectic polysaccharides from the cell walls of Prunus dulcis seeds has an arabinan gly-
cosidic linkage composed of T-Araf: f : (1→5)- Ara f : (1→3,5)-Araf: (1→2,3,5)-Araf in
the relative proportions of approximately 3:2:1:1 (Dourado et al., 2006). This polymer
has also a lymphocyte stimulating effect. Cardoso et al. (2007) reported that the Ara-
binan-rich pectic polysaccharides accounts about 11-19% of the total pectic polymer,
extracted from olive ( Olea europaea L.) fruit pulp. The FTIR spectroscopic studies of
the olive fruit pulp cell wall polysaccharides stated that the pectic polysaccharides are
rich in uronic acid, arabinose, arabinose-rich glycoproteins, xyloglucans, and glucuro-
noxyalans (Coimbra et al., 1999).
The pectic substances extracted from the pulp of unripe fruits of papaya ( Carica
papaya L.) showed that D-glucose, D-galacturonic acid, and L-arabinose are the ma-
jor constituent sugars with a trace amount of rhamnose (Biswas and Rao, 1969). The
study on cherry fruits ( Prunus avisum ) revealed that the pectic fractions are com-
posed of neutral sugarsviz. Rhamnose, fucose, ribose, arabinose, xylose, mannose,
glucose, galactose, and 2-deoxyglucose, which account as 13.9-42.8% of the total
carbohydrates (Barnier and Thibault, 1982). However, the neutral sugars of pectic
substances of plum ( Prunus domestica L.) fruits are completely esterified (Boothby,
1980). An appreciable amount of pectic material as of 0.85% on fresh weight basis
was extracted from kiwi fruits ( Actinidia deliciosa L.), which also exhibited a highly
jellying temperature of 90°C, compared with 63°C for apple pectin. The cell wall
polysaccharides of kiwifruit ( Actinidia deliciosa ) contain the pectic polysaccharides
of the GTC- and KOH-soluble fractions which has more highly branched rhamnoga-
lacturonan backbones than the CDTA- and Na 2 CO 3 -soluble polymers (Redgwell et al.,
2001). The swollen peduncle of cashew nut ( Anacardium occidentalae L.), known as
cashew apple contains the pectic substances which has the methoxyl content of 3.5%,
anhydrouronic acid of 45.10% and jelly-grade of 75. The acidic water soluble fraction
of the polysaccharides of Indian gooseberry ( Phyllanthus emblica L.) was reported
to contain a pectin with D-galacturonic acid, D-arabinosyl, D-xylosyl, L-rhamnosyl,
D-glucosyl, D-mannosyl, and D-galactosyl residues (Nizamuddin et al., 1982). The
analysis on the cell walls of loquat ( Eriobotrya japonica L.) fruit tissues reveals that
the major component polysaccharides are the pectic polysaccharides, accounted up to
70% of the total cell wall polysaccharides (Femenia et al., 1997).
iNdustrial siGNiFiCaNCe oF PeCtiC PolysaCCharides
Over the years, pectin has been used in conventional food processing industrial pro-
cesses such as preparation of jam, jelly, and so on. Pectin was first isolated in 1825
by Henri Braconnot, though the uses of pectin for making jams and marmalades was
known long before. However, in 1930s, pectin was commercially extracted from dried
apple pomace and citrus peels. They have also pharmaceutical and textile applications.
Fruit Processing application
The most important use of pectin is based on its ability to form gels. High methoxyl pec-
tin forms gels with sugar and acid. Oakenfull (1991) reported that hydrogen bonding