Comprehensive sterol and fatty acid analysis in nineteen nuts, seeds, and kernel

Consumption of nuts and seeds is considered to have many beneficial health effects, as lowering cholesterol, incidence of cancer, or enhancement of immunity system. Among the most important lipid constituents of oils present in nuts and seeds are fatty acyls in lipid classes and phytosterols. The aim of the study was to quantify wide profile of fatty acids and phytosterols in 19 nuts, seeds, and kernel commonly available in the Czech Republic. Samples were extracted by the modified Folch procedure. Fatty acid analyses were conducted by gas chromatography. The sterols were derivatized and subsequently measured by HPLC–MS/MS procedure allowing for the separation of isobaric compounds including sterol Δ5–Δ7 isomers. Nuts and seeds contained predominantly oleic (18:1n-9) and linoleic (18:2n-6) acids, rich sources of α-linoleic acid (18:3n-3) were linseed, chestnut, walnuts and hempseed, the last being the best source of stearidonic acid (18:4n-3). The phytosterol analyses revealed majority of β-sitosterol and campesterol with the exception of pumpkin and melon seeds, rich in Δ7 sterols, which were separable from Δ5 isomers. Correlation of sterols and fatty acids content revealed positive correlation between monounsaturated/saturated fatty acids (16:1n-9, 18:1n-9, 20:1n-9, 20:0) and stigmasterol and negative correlation between fatty acids (16:1n-9, 18:1n-9) and sitostanols. In summary, our study revealed the wide profile of fatty acids and phytosterols between different nuts and seeds. Further studies are needed to confirm the positive effect of each nut and seeds for health.