Rapid determination of esterified glycerol and glycerides in triglyceride fats and oils by means of periodate method after transesterification
- 作者：Daniele Naviglio ; Raffaele Romano ; Fabiana Pizzolongo ; Antonello Santini ; Antonio De Vito ; Lorena Schiavo ; Giorgio Nota ; Salvatore Spagna Musso
- 关键词：Glycerol ; Glycerides ; Triglycerides ; Diglycerides ; Fats ; Oil ; Periodate ; Transesterification
- 刊名：Food Chemistry
- 出版年：2007
- 期刊代码：48_03088146
- 类别：abs
- 出版时间：2007
- 卷：102
- 期：1
- 页码：399-405
- 文件大小：228 K
摘要
This paper describes an accurate method to determine esterified glycerol in the glycerides of edible fats and oils and, in general, in all triglyceride fat or oil. Esterified glycerol is released by means of a transesterification reaction with potassium hydroxide in methanol, which simultaneously produces fatty acid methyl esters. Free glycerol is oxidized selectively to formic acid and without any interference in the same environment in which the transesterification reaction occurs by the addition of periodate.
The formic acid produced is then potentiometrically titrated using an acid–base reaction. By knowing the acidic composition and the distribution of the glycerol between triglycerides, diglycerides and monoglycerides, the determination of glycerol also makes it possible to evaluate the content of glycerides present in the fats. The most accurate glyceride determination was obtained by suitably combining the determination of bound glycerol and the distribution of fatty acids obtained by means of gas chromatographic analysis. With little modifications, the proposed method also makes it possible to successfully analyse edible fat in terms of glycerol content in aqueous containing matrixes.