Assessing the concentration of conjugated fatty acids within pomegranate seed oil using quantitative nuclear magnetic resonance (qNMR)

Abstract

Introduction Pomegranate seed is rich in oil, and seed oil of pomegranate consists of conjugated fatty acids with different percentages. Objectives The current contribution covers how to determine percentages of different isomeric conjugated fatty acids. Methods The percentages of these isomers are analysed by quantitative nuclear magnetic resonance (qNMR) using benzoic acid as an internal reference chemical with a well-defined amount. Linear mathematical equations are developed for the quantitative analysis of fatty acids found in pomegranate seed oil. Results The developed approach is utilised for the pomegranate seed oils prepared in the laboratory and tested for commercial samples. Among the oils derived at the laboratory, the Yeni Hicaz pomegranate cultivar seeds yielded the highest fraction of punicic acid. Among the acids, punicic acid was the one with the highest fraction, while linolenic acid was the one with the lowest percentage. Conclusions These results are important in identifying pomegranate seed oils. Among the commercial samples tested with the current approach, only one of them showed similar content analysis as in the laboratory-derived oils.