Green Chemistry and the Biorefinery - The Economic Utilisation of Food Co-Products - page 15

1.2.4 Root Crops
Sugarbeet pulp contains a variety of valuable components, most notably pectin,
a complex polysaccharide consisting of D-galacturonic acid and a series of
neutral sugars such as L-rhamnose, L-arabinose, and D-galactose. 11 Pectins are
used widely in the food industry as gelling agents in jams and are mainly
sourced from apple pomace and citrus peels. Sugarbeet is also a potential
source as it contains a very high amount of pectin, reported to be 15-30% of
the dry weight, and its pectin also offers superior emulsifying properties,
however, poor gelling is observed. Pectin can also be extracted from sunflower
residues at 15-25% dry weight.
The global pectin market stands at 30,000 tonnes and the price ranges from
$11-$13/kg, see Table 1.5. 12 The San-Ei Gen F.F.I. Inc company has recently
developed a process that modifies sugarbeet pectin to offer enhanced emul-
sifying properties and is close to commercialisation. 13

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1.2.5 Wood and Bark
Tannins, or wood polyphenols, are important extracts from wood and bark and
have been used in various products such as leather. Other applications for
tannins include use in particleboard adhesives and anticorrosive primer.
A lucrative market for tannins is developing in the field of medicine where they
have shown to have anti-inflammatory, antiviral, antimicrobial and anti-
parasitic effects.
Another important component called oleoresin is found in pine and other
softwood. The oleoresin, isolated by tapping of living trees, is fractionated into
gum rosin and gum turpentine. Approximately 75% of the global oleoresin
production (over 1,000,000 tons) and processing takes place in China. Rosin is
used in numerous applications ranging from industrial inks to soaps. Rosin can
be used as a glazing agent and is used in medicine and chewing gum. A small
percentage of rosin is also in flux, required for soldering. Other valuable
components of wood that have great potential include phytosterols, flovonoids

.

Table 1.5 The growth in the use of pectin in various
food products.

Application Growth Rate

Fruit preparations 15-20%

Fruit spreads (low-sugar jams) 10% þ

Yoghurt and dairy 15-20%

Acidified milk drinks, high-sugar jams 2-5%

Fruit juices and high-calcium drinks 10-15%

Baked goods, confectionary 5%

Fat replacers 20% þ