ISI 07-2e Determination of Starch in Pulp by Ewers
ISI 07-2e Determination of Starch in Pulp by Ewers 1. Scope The method is applicable to potato and cassava pulp. LT 22 Feb. 1966 Rev. LT 11. Dec. 1997 2. Principle Granular starch is hydrolysed and determined by Ewers polarimetric method. By-product from starch extraction 3. Apparatus 3.1 Analytical balance weighing to the nearest 1 mg. 3.2 Polarimeter with 2 dm tube 3.3 Shaking boiling water bath. 3.4 Volumetric flask, 100 ml with wide neck 3.5 Büchner funnel 4. Reagents 4.1 Dilute hydrochloric acid 0.12 N 4.2 Lead solution, saturated Dissolve 70 g Pb(CH 3 COO) 2 , 3 H 2 O in 100 ml hot distilled water. 5. Procedure Weigh 10.00 g (w 1 ) wet pulp sample. Preparation Slurry sample in 500 ml water and filter through Büchner funnel (3.5) and paper. Wash with 1 l water. Do not let pulp dry out during washing Hydrolysis Transfer washed sample to volumetric flask (3.4) and flush down sample with 60 ml diluted hydrochloric acid (4.1). Place volumetric flask in boiling water bath (3.3) f