essential role in the prevention of several diseases (Jager, 1968), because they are anti-free radicals. We found that
samples 5, have a low content of total tocopherols (633 mg/kg). The roasting of almonds has an influence on total
tocopherols. Indeed, the oils extracted from unroasted almonds have a higher total α-tocopherol content compared to the
samples extracted from roasted almonds (sample 1 versus 2).
Table 7- Composition of tocopherols in samples 1 to 5 (mg/kg)
As part of the development of Argan oil, we conducted a comparative study of the different physico-chemical parameters
of Argan oil according to its mode of extraction and its origin of production. To carry out this work, we selected 5 samples
of Argan fruit located in different geographical localities of Morocco and extracted in different ways (by mechanical
pressing from roasted and non-roasted almonds). The study of the physico-chemical characteristics shows that all the
acidity values of Argan oils are less than 1.40%. This result shows that Argan oil is characterized by low acidity compared
to other vegetable oils (acidity of olive oil ≤2%).
Present study indicates that roasting appears as a parameter influencing the acidity value of Argan oil. This is
because the acidity value is higher in Argan oil samples prepared from unroasted almonds. We also found that the Argan
oil sample from Tamanar batch had a higher acidity value compared to the samples. This finding suggests that
geographic origin may influence acidity values. The results concerning the unsaponifiable rate shows that Argan oil is
characterized by a low unsaponifiable rate (unsaponifiable rate ≤ 0.81%) (Olive ≤ 1.50%) (Charrouf et al., 2008). Argan oil
extraction technology can influence the unsaponifiable level of Argan oil. In fact, the level of unsaponifiable matter in the
sample prepared from roasted almonds is lower (0.56%) than that prepared from non-roasted almonds. Our study also
shows that the roasting and the origin of the Argan fruit have an influence on the reduction of this parameter (samples 1
and 2). Analysis of the peroxide index shows that the sample of Argan oil extracted from roasted almonds has a higher
peroxide content compared to sample 2 (same batch). The determination of the peroxide index seems to be a critical
measure for the evaluation of the quality of Argan oil. The specific extinction and the refractive index give no precise
information on the origin and the method of extraction of Argan oil.
Analysis of fatty acids shows that Argan oil contains 80% unsaturated fatty acids. It is of the oleic – linoleic type and
contains between 29 to 35% of essential fatty acids: linoleic acid (29 to 34%). Its oleic acid content makes this oil
particularly interesting in regulating cholesterol. Our results showed that the percentage of behinic acid (C22: 0) is higher
in the sample which was prepared from the Argan almonds gathered in the Benaiznassen plantation. These variations can
be considered useful markers to ascertain the geographical origin of Argan oils. Sterol analysis shows that the total sterol
levels of Argan oil vary between 130 to 206 mg/100g of fat. The sterolic composition consists essentially of Δ-7-
stigmasterols. The main products are schottenol (or Δ-7-stigmasterol) and spinasterol. It is noted that schottenol and
spinasterol, which are very rare in vegetable oils, can be a parameter for the detection of adulteration of this oil. Two
minority sterols were identified on the basis of their mass spectrum obtained by GC / MS. These are stigmast-8,22-diene
and stigmasta-7,24-28-diene (or Δ-7-avenasterol).
The sterol composition does not show any significant variation. These results agree with those reported in the
literature (Monfalouti et al., 2010). Argan oil is richer in tocopherols (633 to 775 mg / kg) than olive oil (50 to 150 mg /
kg) and hazelnut oil (300 to 550 mg/kg). The results for tocopherols show that the extraction method and roasting can
influence the composition of tocopherols. In contrast, the sample obtained from roasted almonds has a lower content of
total α-tocopherols. Roasting decreases the total α-tocopherol content (Hilali et al., 2005). Analysis of the triglyceride
fraction of Argan oil allowed the separation of individual triglycerides. We note the predominance of triglycerides LLO
(12% -14%), LOO (13% -15%), LOP (14%), OOO (12% -14%), and POO (14% -17%) in l 'Argan Oil. These triglycerides
represent approximately 73% of each fraction of triglycerides in Argan oil. The triglyceride results do not give any specific
information on the geographical origin and the extraction process of the Argan fruit.
The results of this study indicated that the extraction method and the origin of the fruit of the Argan tree can influence the
peroxide index, the rate of unsaponifiable matter, fatty acids (including behinic; C22: 0), the content of α-tocopherol and
triglycerides (SOP). Present study has demonstrated the high quality of Argan oil extracted by mechanical pressing and
the results of this work have helped support the commercialization of Argan oil worldwide.
Citation: Hilali M, El Monfalouti H and Kartah BE (2020). Evaluation of the chemical composition of Argan (Argania spinosa L.) oil according to its extraction method,