Saponification number
The saponification number ( VZ ) is a key figure for the chemical characterization of fats and oils . It is used for their purity testing and quality control. The saponification number is a measure of the acids bound and freely occurring in one gram of fat . It indicates how much potassium hydroxide (in mg ) is necessary to neutralize the free acids contained in 1 g of fat and to split the existing ester bonds ( saponification ). The smaller the mean molar mass of a fat (i.e. the more short-chain fatty acids it contains), the greater the saponification number. In practice it is a back titration . The excess fat sample is refluxed with ethanolic potassium hydroxide solution and the unused amount of KOH is determined acidimetrically by titration with hydrochloric acid in the presence of a color indicator .
Typical saponification numbers of various substances
substance | Area | |
---|---|---|
from | to | |
Rose oil | 8.0 | 21.0 |
Beeswax | 70 | 80 |
China wax | 73 | 93 |
Rice bran wax | 75 | 120 |
Castor wax | 175 | 185 |
castor oil | 186 | 203 |
Nettle seed oil | 186.8 | 186.8 |
Rose hip oil | 189 | 193 |
Cocoa butter | 194.0 | 196.0 |
Isopropyl myristate | 202 | 212 |
Japan wax | 206 | 238 |
Clarified butter | 218 | 235 |
Calculation examples
Web links
- Saponification table at Waschkultur.de accessed on July 7, 2013
Individual evidence
- ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, 1985, p. 654, ISBN 3-342-00280-8 .
- ↑ Reinhard Mattisek, Gabriele Steiner, Markus Fischer: Food Analysis . 4th edition. Springer, Berlin 2010, ISBN 978-3-540-92205-6 .
- ^ Organikum , Wiley-VCH Verlag GmbH, 23rd edition, 2009, pp. 498-499, ISBN 978-3-527-32292-3 .
- ↑ Bruno and Paschke: Detection of foreign fats in cocoa butter , magazine for food investigation and research issue 60, number 3 / September 1930 doi : 10.1007 / BF01664060 .