|Home||Profile||Market Place||Sweeteners||Lab Methods||Glossary||Search|
|Master Index||Environment||Application||Starch||Statistics||Tables||Write us|
International Starch Institute
Science Park Aarhus, Denmark
ISI 12-1e Determination of Acidity
|1. Scope||The method is applicable to starch milk and hydrolysates
|LT 12. Dec. 1966
Rev. LT 16. Dec. 1997
|2. Principle||Titration with NaOH to pH 8.3.
|3. Apparatus||3.1 Burette|
|3.2 pH meter|
|3.3 Volumetric flask 50 ml
|4. Reagents||4.1 Sodium hydroxide 0.1 N|
|4.2 Phenolphtalein: 1 g in 1 l ethanol 90%
|5. Procedure||Fill volumetric flask (3.3) with liquid sample. Transfer to 300 ml conical flask.|
|Add 1 ml (4.2) and titrate with (4.1) to faint persistent pink||or use pH meter to 8.3|
|V = ml (4.2). N = normality of (4.2)
|6. Calculation||Calculate acidity as normality N of sample by averaging results of two
samples with one decimal.
N = N V / 50
|7. Notes||J. Assoc. Off. Anal. Chem. 66 (1983) no. 6, 1395-1399 recommend pH 6.0 as end point, but AOAC limits this method to HFCS.|
|Ph. EUR 4ed acidity test for starch. Add 10 g sample to 100 ml of alcohol (70 per cent V/V) R previously neutralised to 0.5 ml of phenolphthalein solution R and shake for 1 h. Filter and take 50 ml of the filtrate. Not more than 2.0 ml of 0.1 M sodium hydroxide is required to change the colour of the indicator.|
|8. Reference||AOAC Official Methods of Analysis (15th edition)|
| Top of Page | LabIndex |
Copyright© 1999. Read Disclaimer notice.
All rights reserved. International Starch Institute, Science Park Aarhus, Denmark.
Keywords: laboratory method determination acidity starch hydrolysate