Characterization of Moringa oleifera seed oil from drought and irrigated regions of Punjab, Pakistan

Abstract

The aim of the present study was to investigate the composition of M.oleifera seed oil from drought and irrigated regions of Pakistan. The hexane-extracted oil content of M.oleifera seeds harvested from one drought (Layyah) and two irrigated regions (Rahim Yar Khan, Jhang) of Punjab, Pakistan was found to be 30.36 and 35.26, 38.37% respectively. Results of physical and chemical parameters of the extracted oils were as follows: iodine value, 65.86 and 70.50, 67.86; refractive index (40°C), 1.4570 and 1.4582, 1.4581; density (24°C), 0.9059 and 0.9069, 0.9002 mg mL-1; saponification value, 181.1 and 183.7, 183.1; unsaponifaiable matter, 0.84 and 0.85, 0.97%; acidity (as oleic acid) 0.28 and 0.35, 0.33%. The induction period (Rancimat 20L/h, 120°C) of the M.oleifera oil from the drought region was significantly higher (9.63 h) as compared with those of irrigated regions (8.74, 8.33 h). Specific extinctions at 232 and 270 nm were 1.92 and 1.98, 1.68; 1.02 and 0.97, 0.75 respectively. The overall contents of tocopherols (α, γ and δ), which did not differ significantly in the Moringa oils from both regions ranged from 95.85-103.80, 80.26-86.56 and 55.75-64.55 mg kg-1 respectively. Fatty acid profiles of the M.oleifera oils from drought and irrigated regions of Punjab consisted in a high level of oleic acid (up to 72.68 and 75.55, 74.66 %) followed by palmitic and behenic acid (up to 9.26 and 8.76, 9.20 and 5.46 and 3.72, 4.53 %) respectively. Results of various physical and chemical parameters of the investigated M.oleifera seed oils revealed that drought is one of the most visible factors that have amplified the induction period and C22:0 content of the oils and reduced seed weight, oil yield, iodine value and C18:1 content.