Fatty Acid Composition of Cosmetic Argan Oil: Provenience and Authenticity Criteria

Abstract

In this work, fatty-acid profiles, including trans fatty acids, in combination with chemometric tools, were applied as a determinant of purity (i.e., adulteration) and provenance (i.e., geographical origin) of cosmetic grade argan oil collected from different regions of Morocco in 2017. The fatty acid profiles obtained by gas chromatography (GC) showed that oleic acid (C18:1) is the most abundant fatty acid, followed by linoleic acid (C18:2) and palmitic acid (C16:0). The content of trans-oleic and trans-linoleic isomers was between 0.02% and 0.03%, while trans-linolenic isomers were between 0.06% and 0.09%. Discriminant analysis (DA) and orthogonal projection to latent structure—discriminant analysis (OPLS-DA) were performed to discriminate between argan oils from Essaouira, Taroudant, Tiznit, Chtouka-Aït Baha and Sidi Ifni. The correct classification rate was highest for argan oil from the Chtouka-Aït Baha province (90.0%) and the lowest for oils from the Sidi Ifni province (14.3%), with an overall correct classification rate of 51.6%. Pairwise comparison using OPLS-DA could predictably differentiate (≥0.92) between the geographical regions with the levels of stearic (C18:0) and arachidic (C20:0) fatty acids accounting for most of the variance. This study shows the feasibility of implementing authenticity criteria for argan oils by including limit values for trans-fatty acids and the ability to discern provenance using fatty acid profiling.

Combination of Stable Isotopes and Fatty Acid Composition for Geographical Origin Discrimination of One Argan Oil Vintage

“…Many approaches have been used for the identification of geographical origin, such as fatty acid composition [20] and Fourier transform infrared fingerprinting [11] combined with chemometric tools as linear discriminant analysis (LDA) and partial least squaresdiscriminant analysis (PLS-DA) [21]. It was shown by Taous et al [22] that the pedo-climatic parameters and the isotopic composition of argan oil are linked.…”

“…Isotopic analysis of the chemical elements of seed extract can help to understand different ecological processes (temperature, precipitation, air humidity) and their influence on the development and physiology of plants during the seed development period, the results generally allow the development of analytical tools to verify the origin of plant material [23]. Miklavčič et al [20] reported that the fatty acid profile can be used as a tool for confirming the geographical origin of Argan oil. It was recommended as a method for laboratories due to its simplicity, rapidity, and efficiency.…”

Special Issue “Isotopic Techniques for Food Science”

“…This special issue also includes several papers that use stable isotope ratios, elemental profiles, and fatty acid composition to assure the authenticity and origin of high-quality products typical of the national identities of Mediterranean countries such as Moroccan argan oil [ 8 ], Portuguese meat products from Iberian black pigs [ 9 ], and Slovenian truffles [ 10 ]. These studies form part of the REALMed project “Pursuing authenticity and valorization of Mediterranean traditional products” (ARIMNET 2 call 2016) that aimed to provide reliable technological tools for authentication and quality assessment and make these tools widely available to stakeholders and consumers and promote traditional knowledge and the sustainable development of local economies [ 11 ].…”

“…These studies form part of the REALMed project “Pursuing authenticity and valorization of Mediterranean traditional products” (ARIMNET 2 call 2016) that aimed to provide reliable technological tools for authentication and quality assessment and make these tools widely available to stakeholders and consumers and promote traditional knowledge and the sustainable development of local economies [ 11 ]. The study performed on cosmetic argan oil shows the feasibility of implementing authenticity criteria for argan oils by including limit values for trans-fatty acids and the ability to discern provenance using fatty acid profiling [ 8 ]. The research performed on truffles indicated that elemental and stable isotope composition together with multivariate statistical analysis classified truffles according to species and geographical origin [ 10 ].…”

“…Some of the manuscripts [ 3 , 4 , 8 , 10 ] presented their raw data in the supplementary material supporting the open-access of research data. Much of this data is also in the e -component of different projects such as METROFOOD-RI research infrastructure and FNS-Cloud.…”