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Fatty Acids Composition and Oxidation Kinetic Parameters of Purslane ( Portulaca oleracea ) Seed Oil

Research paper by Seyedeh Razieh Jalali Mousavi, Razieh Niazmand

Indexed on: 21 Nov '17Published on: 01 Dec '17Published in: Agricultural Research



Abstract

Purslane seed oil (PSO) was evaluated for fatty acids composition and lipid oxidation. Results showed that linoleic acid (C18:2, 33.63%), α-linolenic acid (C18:3, 26.77%), palmitic acid (C16, 16.43%), and oleic acid (C18:1, 16.36%) were the dominant fatty acids in the PSO. The saturated fatty acids of the PSO amounted to 21.09% of the total fatty acids, while the unsaturated fatty acids amounted to 78.9%. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of purslane seed water–methanolic extract at different concentrations varied significantly, ranging from 15.41 to 79.06%. PSO was oxidized at three temperatures (353, 363, and 373 K) under Rancimat test conditions. Reaction rate constants (k), activation energies (E a), Q 10 number, activation enthalpy (ΔH ++), and activation entropy (ΔS ++) for oxidative stability of PSO were calculated according to the activated complex theory and Arrhenius equation. The k, E a, Q 10, ΔH ++, and ΔS ++ for PSO ranged from 0.031 to 0.186 h−1, 93.46, 2.37, 90.54 kJ mol−1, and −18.62 J K−1 mol−1, respectively. Lipid oxidation rates were greatly dependent on temperature. According to fatty acid composition and high polyunsaturated fatty acids (61.88%) of PSO, it has a high E a, ΔH ++, and ΔS ++.