Micromoles PA x molecular weight of PA = micrograms of
PA.
The phytate content = 185.82/660.8 x micro PA =
microgram phytate.
% Phytic acid content = microgram PA/microgram phytate x
100/1.
Determination of oxalate.
This determination was done using the method described
by Oke
[13].
Oxalate was determined by extracting 5.0g of
the sample with 20cm3
of 0.3M HCl. The extraction was
done three times by warning it at 40o
C. The combined
extract was diluted to 100ml with distilled water for total
oxalate estimation.
Oxalate estimation.
5.0cm3
of the extract was made alkaline with 5M
ammonium hydroxide and three drops of phenolphthalein
indicator was added.1ml of 5% CaCl2 was then added and
the mixture was allowed to stand for 3hrs after which it was
centrifuged at 3000rpm for 15 minutes. The supernatants
were discarded and the precipitates washed thrice with hot
water 2.0cm3
of 3M sulphuric acid was added and warmed
in a water bath at 80o
C to dissolve the precipitate. It was
then titrated with freshly prepared 0.01M KMno4. The
titration was carried out at normal temperature at first until it
was colourless. The solution was then warmed to 70o
C and
titrated until a pink colour persisted.