Taneva, S; Mechqoq, H; Totseva, I; Nikolova, Y; Kamenova-Nacheva, M; Yaagoubi, ME; Msanda, F; Aouad, NE; Dimitrov, V; Momchilova, S
The argan (Argania spinosa L., Sapotaceae) kernels and cactus Opuntia ficus indica L. (Cactaceae) seeds were processed to obtain oils by Soxhlet extraction with hexane and by cold pressing. The aim of our investigation was to evaluate the oil yield, lipid composition (neutral lipid classes, fatty acids and tocopherols) as well as oxidative stability (induction periods and conjugated dienes) of argan and cactus oils depending on the extraction method. The results showed that solvent extraction ensured higher oil yield compared to cold pressing, with values respectively of 59.5 % and 40.8 % for argan oil, and 11.7 % vs. 2.6 % for cactus oil. Estimation by high-performance thin layer chromatography (HPTLC) of the neutral lipid classes profiles revealed the triacylglycerols as predominant lipid class and presence of minor amounts of sterol esters, free sterols, diacylglycerols, free fatty acids and polar lipids. Traces of monoacylglycerols and tocopherols were detected as well. No effect of the extraction method on the neutral lipid classes profiles was observed. Likewise, no significant differences in fatty acids composition, tocopherols content and oxidative stability were correlated with the method for oil production. Fatty acids were quantified by gas chromatography (GC) of their methyl esters whereat linoleic (cis,cis 9,12-18:2), oleic (cis 9-18:1), palmitic (16:0) and stearic (18:0) acids were main components, respectively of 60%, 17%, 13% and 4% in cactus oils, and of 33%, 46%, 14% and 6% in argan oils. Tocopherols were measured by high-performance liquid chromatography (HPLC) in amounts of 16 mg kg-1alpha-tocopherol in argan oil and 9 mg kg-1in cactus oil whereas gamma-tocopherol was accordingly 385 mg kg-1and 450 mg kg-1oil. The absorption values for conjugated dienes (presented by K232) were 2 and 4, with induction periods of oxidation at 100oC of 21 h and 3 h for argan and cactus oils, respectively. Thus, the tested two extraction methods had effect only on oil yield. © 2021. All Rights Reserved.