design a procedure to indicate the amount of starch present

design a procedure to indicate the amount of starch present in various plant tissues samples. how would you weigh your samples? how would you test your sample? how would you quantify the iodine test?

Solution

There can be various procedure to quantify the amount of starch. i would mention a one which is listed in literature.

Plant tissue for estimation can be dissected by the PALM® MicroBeam System (Carl Zeiss Microimaging GmbH, Bernried, Germany). following which tissue elements can be taken by use of a microneedle and transferred into an glass tube for the extraction of starch. Now here you can weight the tissue amount. For extraction of starch, 100 l 15% HCl used to added to the tissue residue on the filter membranes and incubated 30 min at 80°C. Cool the sample and were centrifuged for 1 min at 13000 rpm and diluted with 60 l 10% methanol.

Steps

Anthrone reagent: dissolve 1 g of anthrone in 500 mL of 72% sulphuric acid

Pipette 1.0 mL of test solution and same amount of control in another tube of 10-mL test tube and cool to 0ºC on ice Add 5 mL of ice-cold anthrone reagent.

Heat for exactly 11 minutes at 100ºC (in water bath) and cool rapidly to 0ºC on ice 6. Read A630 (against water) within an hour (Turn on spectrophotometer and let warm up 2.)

test to be compared with control and calculate the amount of starch in test

Amount of starch in test= OD of test* amount of starch in control/OD of control

Same was we can quantify the iodine test using the control. Here instead of anthron reagent we use  IKI solution—iodine dissolved in an aqueous solution of potassium iodide which gives blue intense colour with starch.

Colour OD of test can be compared with control with known concentration of starch and amount can be calculated using above formula.