Phenolic composition of Argan Oil

Colorimetric Evaluation of Phenolic Content and GC-MS Characterization of Phenolic Composition of Alimentary and Cosmetic Argan Oil and Press Cake

LUIS B. ROJAS, STEÄPHANE QUIDEAU, PATRICK PARDON AND ZOUBIDA CHARROUF

The following is a section of the article. View full article >

In conclusion, this analytical study of different argan oil samples (traditional, cosmetic, and alimentary grades) and their corresponding press cakes showed that their content of phenolic compounds is relatively low as determined by GC-MS analysis of their silylated methanolic extracts and evaluation of their total phenolic content by the Folin-Ciocalteu method. Furthermore, the argan oil phenolic composition appeared to be highly dependent on technical extraction factors, as well as handling and storage factors, as alluded to from the apparent oxidative degradation that some samples underwent, with variations observed both qualitatively and quantitatively. Differences between results of this work and those in the literature can also be attributed to the influence of geographical location of argan tree, as it has been recently demonstrated by Charrouf and coworkers (15).

The influence of the extraction process used can be clearly pointed out not only from the analysis of the oil samples but also from their corresponding press cakes at different pressure times. The press cakes retained the highest amount of phenolics,as evidenced in this work for the first time. Their concentration of phenolics is however not as high (i.e., from about 25 to 483 mg/kg by the weight of the dried material) as that found in olive oil press cakes in which it can reach up to 1 wt % of the dried material (20). This study only constitutes a preliminary assessment of the complete phenolic profile of argan oils and press cakes, and the general observations made here will need to be firmly established from the analysis of a larger and more diverse collection of samples. Nevertheless, it should be pointed out that 9 phenols (i.e., 3-hydroxypyridine (3-pyridinol), 6-methyl- 3-hydroxypyridine, catechol, resorcinol, 4-hydroxybenzyl alcohol, vanillyl alcohol, 4-hydroxy-3-methoxyphenethyl alcohol, epicatechin, and catechin) out of the 11different phenols detected here by GC-MS analysis were identified in alimentary and cosmetic argan oils for the first time. The analysis of the press cake revealed 16 phenols, among which 6 new ones not presentin oils were identified (vanillin, 4-hydroxyphenylacetic acid, 3,4-dihydroxybenzyl alcohol, methyl 3,4-dihydroxybenzoate, hydroxytyrosol, and protocatechuic acid).
View full article >