2.11 Determination of Starch
The starch content was determined
by Lane and Eynon method. Rice powder (5g) was taken in a beaker and 30 ml of
water was added. It was transferred to the water bath and heated at 60ºC for
25min.Then 100ml of 95% ethanol was added to it and stirred by magnetic stirrer
for 15 min. It was filtered through Whatman filter paper no. 2 .The residue was
soaked in the 50% ethanol solution for 1hr.After that, the residue was washed
on the filter paper with the 50% ethanol solution for 4 hrs. The residue was collected to a round
bottom flask and 100 ml of water and 20 ml of HCl added to it. The flask was
attached with the condenser and heated for 2.5hrs.Then it was allowed to cool
and neutralized by adding NaOH solution (40%). 10ml of Fehling solution was taken in to a conical
flask and titrated against neutralized sample solution. When CuSO4 .5H2O
like color was observed, then 3 drops of methylene blue indicator was added and
continued titration. The end point was indicated by brick- red color.
The
starch content was calculated by following formula:
i)
ii) (%)
starch
(%) Reducing
sugar×0.9
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