Research of the chemical composition peculiarities of food additives – vegetable lecithins for the development of methods for assessing their quality

Abstract

Lecithins are widely used in the food industry as food additives. In this regard, the requirements for the lecithins quality are quite high, and the development of the rapid determination methods of their quality indicators, including the acid value, is an urgent task. The article presents research of the peculiarities of vegetable lecithins chemical composition for the development of a method for determining their acid value using the pulsed nuclear magnetic relaxation (NMR) method. It was found that the studied lecithins differ significantly in the content of individual phospholipid groups exhibiting acidic properties. As a result of the research of the fatty acid composition of the lecithins acetone-soluble fractions, it was found that the highest total content of monounsaturated fatty acids is a characteristic of sunflower oleic type lecithins (81.3 %) and rapeseed lecithins (66.3 %), and polyunsaturated fatty acids – sunflower linoleic type lecithins (63.6 %) and soybean lecithins (67.7 %). Researches of the NMR characteristics of lecithins with the introduction of carbon tetrachloride (CCl4) have been carried out. It was found that the redistribution of component composition in the “lecithin-CCl4” system occurs at different ratios for each type of lecithin, which is due to their chemical composition peculiarities.