Argan oil is a traditional product obtained from the fruits of the argan tree (Argania spinosa L.), which is endemic only to Morocco. It is commercialized worldwide as cosmetic and food-grade argan oil, attaining very high prices in the international market. Therefore, argan oil is very prone to adulteration with cheaper vegetable oils. The present work aims at developing novel real-time PCR approaches to detect olive and soybean oils as potential adulterants, as well as ascertain the presence of argan oil. The ITS region, matK and lectin genes were the targeted markers, allowing to detect argan, olive and soybean DNA down to 0.01 pg, 0.1 pg and 3.2 pg, respectively, with real-time PCR. Moreover, to propose practical quantitative methods, two calibrant models were developed using the normalized ΔCq method to estimate potential adulterations of argan oil with olive or soybean oils. The results allowed for the detection and quantification of olive and soybean oils within 50–1% and 25–1%, respectively, both in argan oil. Both approaches provided acceptable performance parameters and accurate determinations, as proven by their applicability to blind mixtures. Herein, new qualitative and quantitative PCR assays are proposed for the first time as reliable and high-throughput tools to authenticate and valorize argan oil.
This work was supported by the FCT (Fundação para a Ciência e Tecnologia) through
projects FCT/CNRST (Portugal/Morocco) (FCT/6460/6/6/2017/S) and the strategic funding of
UIDB/50006/2020 | UIDP/50006/2020. This work was also funded by the European Union (EU)
through the European Regional Development Fund (FEDER funds through NORTE-01-0145-FEDER-
000052) and the project SYSTEMIC (Knowledge Hub on Food and Nutrition Security, ERA-Net
Cofund ERA-HDHL no. 696300). J. Costa and I. Mafra thank the FCT for funding through the
Individual Call to Scientific Employment Stimulus (2021.03583.CEECIND/CP1662/CT0012 and
2021.03670.CEECIND/CP1662/CT0011, respectively). L. Grazina is grateful to the FCT for the grant
(SFRH/BD/132462/2017) financed by POPH-QREN (subsidized by FSE and MCTES). The authors are grateful to the Groupement des Coopératives Targanine for
supplying the argan oil sample. J.S. Amaral is grateful to the FCT for financial support through
national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 e UIDP/00690/2020) and
SusTEC (LA/P/0007/2020).
