PHYSICOCHEMICAL PROPERTIES AND COMPOSITION OF LIPID FRACTION OF SELECTED EDIBLE NUTS

The study presents the characteristics of oil fraction of 8 types of edible nuts available on the Polish market. All tested nuts were characterized with high content of dry matter. Fatty acid and sterol composition was analyzed by GC-MS. Squalene and tocopherol profiles were examined by HPLC with diode array (DAD) and fluorescence detectors (FLDs). The highest level of fat was found in macadamia (75.4 g/100 g) and the lowest in cashew nuts (46.9 g/100 g). Fatty analysis showed that nuts were rich in unsaturated fatty acids. Monounsaturated fatty acids were predominant in most cases, with the exception of Brazilian nuts, walnuts and pine nuts which were richer in polyunsaturated fatty acids. β-Sitosterol was the main sterol of nuts, and its content ranged from 96.9 mg/100 g of oil (in macadamia) to 474.8 mg/100 g of oil (in pistachio). γ-Tocopherol homologue was predominant among its fraction with the largest content determined in pistachio (8.3 mg/100 g of oil) and walnuts (8.6 mg/100 g of oil). The presence of squalene was confirmed in seven types of nuts, and the richest source of it were Brazilian nuts (145.8 mg/100 g of oil). The study proofs the variation of nut oil composition, especially phytosterol and tocopherol content and can be used for better characterization of nuts derived from different geographic areas or cultivars