Quality Control of Argan Oil
Argan oil undergoes numerous analytical and sensory tests to determine its overall quality. These tests evaluate the freshness of the oil by assessing hydrolytic and oxidative changes, ensuring that the product conforms to its labeling. For instance, “extra virgin argan oil” can be analyzed using simple tests like free fatty acids, peroxide value, and specific extinction (E270 and E232), as well as purity blending with other oils and contaminants. These tests also require detailed analyses of triglyceride contents, fatty acids, sterols, tocopherols, and more. Additionally, the taste, odor, and color of the oil must be considered as part of its organoleptic characteristics.
Like other vegetable oils, argan oil can undergo natural changes due to oxidation. These changes can be controlled from fruit harvest to oil storage by monitoring physicochemical criteria such as acidity, peroxide value, and specific extinction at wavelength 270 (E270). The Moroccan Standard (08.5.090) uses acidity to classify argan oil into four grades: extra-virgin, fine-virgin, ordinary virgin, and lampante virgin argan oil. The acidity of extra-virgin argan oil must be less than 0.8 g/100 g. The oxidative state of the oil can be evaluated using peroxide value and specific extinction coefficient (E232), which indicates the presence of primary oxidation products. The peroxide value of extra-virgin argan oil should be lower than 15 mEq O2/kg. The other two indices used to assess secondary oxidation products are p-anisidine value and specific extinction E270, with the Moroccan Standard fixing the limit value for extra virgin argan oil at 0.25. Furthermore, the purity of argan oil requires quantifying major compounds such as fatty acids, minor compounds like sterols, polyphenols, tocopherols, and mineral elements, as well as identifying contaminants like heavy metals, some mycotoxins, aromatic hydrocarbon polycyclics (PAHs), phthalates, and pesticides.
While physicochemical characterization is a crucial step, it is not sufficient to meet consumer expectations. Therefore, organoleptic characteristics like taste, smell, and color must also be considered, especially for food argan oil. An organoleptic analysis is a necessary criterion for successful food marketing and an integral part of evaluating food argan oil.
