Fatty acids, sterols and tocols in Irish barley varieties: Profiling and correlation analysis

The objective of this study was determination and comparison of three types of lipophilic phytochemicals, fatty acids, phytosterols andtocols, in five whole grain Irish barley varieties. Fatty acids and sterols were derivatised and analysed by gas chromatography, while tocols were analysed by high performance liquid chromatography. The content of saturated and unsaturated fatty acids in the varieties ranged between 442-2615 and 1200-1730 mg/100 g dw, respectively, indicating abundance of unsaturated fatty acids in barley. Linoleic acid was the most abundant unsaturated fatty acid. Phytosterols in the barley varieties ranged between 66 and 82 mg/100 g dw with beta-sitosterol being the most abundant sterol, while tocols ranged between 46 and 58 mu g/g dw with alpha-tocotrienol being the most abundant tocol homologue. Principle component analysis (PCA) revealed interesting correlations between these phytochemicals. An evident relationship between the unsaturated fatty acids and some tocol homologues was observed. Sterols like beta-sitosterol and beta-sitostanol were negatively correlated with each other. PCA also indicated possible genotypic relationships between the barley varieties. Practical applications: Barley lipids serve as a considerable source of major fatty acids, phytosterols and tocols. By means of fractionation such as milling, enriched sources of these phytochemicals for use as ingredients in functional foods might be produced. Concurrent analysis of phytochemicals undertaken in this study, along with determination of correlations between them provides useful information to geneticists and plant breeders, in choosing specific varieties/genotypes and producing crossbreeds with improved levels of certain phytochemicals.