ISI 11-1e Determination of pH and Acid Factor of Starch
ISI 11-1e Determination of pH and Acid Factor of Starch 1. Scope The method is applicable to commercial native starch LT 02. Dec. 1964 Rev. LT 16. Dec. 1997 2. Principle Titration of 40 g starch in slurry with acid to pH 3.0. 3. Apparatus 3.1 Analytical balance weighing to the nearest 0.1 mg. 3.2 pH meter 4. Reagents 4.1 Hydrochloric acid 0.1 N 5. Procedure Weigh 40.0 g sample to the nearest 100 mg in a 250 ml beaker Add 100 ml distilled water and stir. pH Note pH of slurry Titration Titrate with burette and (4.1) to pH = 3.0 V = ml (4.2). N = normality of (4.2) 6. Calculation Calculate acid factor of sample by averaging results of two samples with one decimal. Acid factor = 10 N V Report pH of starch slurry as pH of starch with one decimal. Eventually correct to value on sample dry matter.