Physicochemical Study and Composition of Argania spinosa Oil from Two Regions of Algeria

Abstract

rich in essential polyunsaturated fatty acids. It is a source of oleic acid (47.7%) and linoleic acid (29.3) [10] and is rich in minor and noble compounds like tocopherols, polyphenols, sterols, carotenoids, xanthophyls, squalene [11], and saponins [12]. Many scientific studies have reported that the oil has many pharmacological effects, such as antioxidant [13], antiproliferative [14], cardioprotective [15], and hypolipemiant [16] activities. The aim of this present work was to determinate the composition of fatty acids and triacylglycerols of oils obtained from seeds of trees growing in two different regions of Algeria (Tindouf and Mostaganem) and to assess its physical and chemical parameters. The results will furthermore be important as an indication of the potential nutrient and economic utility of argan oil of Algeria as a new source of edible lipids. Table 1 presents the physical and chemical characteristics of argan oil of the two regions. The physical characteristics, density, refractive index, and absorbance in UV at 232 and 270 nm for argan oil of the two regions (Mostaganem and Tindouf) are comparable and compatible to the values reported by Moroccan standard (MS: 08.50.90) [10]. These values are consistent with those described in the MS (08.50.90) for which the values of the density for argan oil generally vary between 0.906–0.919 (at 20°) and for refractive index (at 20°) between (1.463–1.472) [10]. The absorbance in ultraviolet provides information on the quality of oils. The absorption at 232 and 270 nm is due to the presence of conjugated diene and triene systems. The degree of oxidation of the oil is reflected in its specific extinction at 232 and 270 nm. In fact, oils of good quality contain very few products of oxidation. Argan oil showed few absorbance at 232 and 270 nm. The chemical parameters of oil are as follow: the free fatty acids (FFA) value is 0.11–0.12%, this rate is much lower than the upper limit value (15%) established by the Moroccan standard (MS: 08.50.90) [10]. It means, we can confirm that our oils are virgin and not be altered. The iodine value (97.02 and 101.45) was due to its high content of unsaturated fatty acids (Table 1). The peroxide value (2.65 and 2.60 meqO 2 /kg oil) was below the limit of 20 meq of oxygen/kg of oil, showing the relative stability to oxidation of these oils. The saponification value (190.79 and 188.55) was lower; all these values agree with MS (08.50.90) [10]. The major fatty acids present in argan oil were oleic, linoleic, palmitic, and stearic acids (Table 2). Oleic and linoleic acid were the main unsaturated fatty acids in argan oil (MS: 08.50.90) [10]; 79.88% of the compounds identified in argan oil are unsaturated fatty acids (UFA), and 20.12% are saturated fatty acids. The oleic acid content reached 50.30% for argan oil from Tindouf and 45.02% for Mostaganem. The oil of Tindouf contains 28.99% linoleic acid, while that of Mostaganem contains 36.80%. These results concurred with those reported by [17].