Tamarind monograph.pdf - Crops for the Future

set at 2.0% beyond which the jellies were hard and difficult to chew. Two
per cent polyose from TKP adequately substitutes 1% pectin in ready-to-eat
jelly.
Jellose is prepared on a large scale by adding TKP to 30-40 times its weight
of boiling water, containing citric or tartaric acid at a concentration of 0.2%.
It is then stirred vigorously and boiled for a further 30-40 minutes. The
solution is kept overnight for setting and the supernatant liquid is siphoned
off and concentrated under vacuum, passed through a filter press and then
dried in a drum drier. The resultant product is pulverised in a ball mill. A
good sample of jellose should have a relative viscosity of 5.0% at 35º C in
0.5% solution, which is somewhat higher than corn starch. Jellose is much
cheaper than corn starch and is required in smaller quantities.
An invention for the extraction of polysaccharides from seed kernels has
been developed and patented by Gordon (1968). As the pulp also contains
pectin, an integrated process has been developed for the production of
pectin, tartarates and ethanol. In this process, the pulp is repeatedly extracted
with boiling water and the filtered extract is cooled to separate potassium
bitartarate. The supplement is concentrated under vacuum and the pectin is
separated by the addition of alcohol. The filtrate, after recovering the
alcohol, is treated with lime to precipitate calcium tartarate. The remaining
sugars are fermented with yeast and alcohol is recovered. The recovery is
about 2.5% pectin, in addition to 12% tartaric acid and 12% alcohol, which
makes the process economic and attractive. Krishna (1955) reported a
process for the extraction of tartarates with acidified ethanol and subsequent
extraction of pectin. After removing the alcohol, the residual syrup could be
used for edible purposes. This process has been patented under the Indian
Bureau of Standards, Indian Patent No: 52, 1955. Tamarind pectin resembles
apple pectin and has the following composition (Table 3.1).
Table 3.1 Average chemical composition of tamarind pectin
Constituent Per cent
Moisture 7.7-8.9
Ash 2.3-3.0
Calcium pectate 70.0-80.4
Methoxyl 7.9-9.9
Uronic acid 43.0-56.4
3.6.3 Tamarind juice concentrate
Tamarind juice concentrate (TJC) is a convenient product, as it is easy to
dissolve and reconstitute in hot water (Anon, 1982 b). It can also be stored
for long periods. Tamarind juice concentrate is prepared by extracting
cleaned pulp with boiling water using the counter current principle, where
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