ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

B.C.l Esterification ofbeta-sitosterol
200 mg ofbeta-sitosterol was dissolved in 200 mg ofoleic acid at 80· C. The solution was
added to 80 m! of a three per cent solution of sodium caseinate at 60-80· C under strong
stirring.
B.C.2 Analyses ofdigestive enzyme activities
B.C.2.1 Preparation oftissues
The intestine of each rat was divided into two portions: the proximal segment (duodenum)
representing the upper intestine, and the mid and distal segments Gejunum and ileum)
representing the lower intestine. The rat intestine was free offood and rinsed in 0.9 per cent
NaCL A fraction was prepared from the two parts ofthe intestine by homogenizing the parts
in 00 M phosphate buffer. The homogenate was centrifuged at 10000 x g for 10 minutes
and the supernatant was frozen until required for enzymatic assays.
B.C.2.2 Imaccharidases [DahIqvist (1968)]
The principle of this method is as follows: an intestinal homogenate is incubated with the
appropriate disaccharide. The disaccharidase activity is then interrupted by boiling the
solution and the glucose liberated is measured with a glucose-oxidase reagent. Five hundred
microlitres of substrate at 56 mM was added to 200 J.L1 of homogenate (100 III for sucrase
and maltase) and incubated for 60 minutes at 37· C (15 minutes for maltase). The reactions
were terminated by incubating at 100· C for five minutes. The liberated glucose was
measured, using a Glucose (GO) Assay kit. The absorbance of each tube was measured
spectrophotometrically at 540 nID.
The activity was calculated as follows:
Units/m! ofhomogenate =
Key
Ilg glucose x F
180x60xN
F = dilution factor ofthe homogenate (1.6 for the sucrase and maltase; 1.4 for the lactase);
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