Robust and Reliable Quantification of Phospholipids in Edible Oils Using 31P NMR Spectroscopy

Abstract

Upon storage, crude plant oils will form a solid sediment called gum, which consists mainly of phospholipids (PL). PL are removed during the production of edible oils by a process called degumming. A higher yield is recognized as a major advantage of enzymatic degumming over traditional processes. Robust and accurate PL quantification methods are needed to develop and monitor enzymatic degumming processes. Several techniques, such as atomic emission spectroscopy, liquid chromatography, and thin-layer chromatography, have been applied for the quantification of PL in edible oils. In the past decade, 31P NMR spectroscopy has been shown to have advantages over these techniques because of the possibility of the simultaneous, fast, and accurate quantification of different PL directly in the oil. This article demonstrates the application of 31P NMR spectroscopy as a method for the quantification of all relevant PL and phosphorous-containing degradation products in crude and refined oils. In addition, the validation results show that this method is robust because the limit of detection is as low as 5 μmol/100 g oil. Variations of less than 5% were obtained for all P-containing compounds present in the oils at concentrations above 100 μmol/100 g oil.