Can the water quality influence the chemical composition, sensory properties, and oxidative stability of traditionally extracted argan oil?

Article type: Research Article

Authors: Boukyoud, Zaineb^{a; 1} | Ibourki, Mohamed^{a; e; 2} | Gharby, Said^{a; 3; *} | Sakar, El Hassan^{b; 4} | Bijla, Laila^{a; 5} | Atifi, Hajar^a | Matthäus, Bertrand^{c; 6} | Laknifli, Abdelatif^{a; 7} | Charrouf, Zoubida^{d; 8}

Affiliations: [a] Laboratory Biotechnology, Materials and Environment (LBME), Faculty Polydisciplinary of Taroudant, University Ibn Zohr, Agadir, Morocco | [b] Department of Biology, Faculty of Sciences of Tetuan, Abdelmalek Essaâdi University, Mhannech II, Tetuan, Morocco | [c] Max Rubner-Institut, Federal Research Institute for Nutrition and Food, Department for Safety and Quality of Cereals, Working Group for Lipid Research, Schützenberg 12, 32756 Detmold, Germany | [d] Laboratory of Plant Chemistry and Organic and Bioorganic Synthesis, Faculty of Sciences, Mohammed V University, Rabat, Morocco | [e] African Sustainable Agriculture Research Institute (ASARI), Mohammed VI Polytechnic University (UM6P), Laayoune, Morocco

Correspondence: [*] Corresponding author: Said Gharby, Laboratory Biotechnology, Materials and Environment (LBME), Faculty Polydisciplinary of Taroudant, University Ibn Zohr, Agadir, Morocco. E-mail: s.gharby@uiz.ac.ma.

Note: [1] https://orcid.org/0000-0003-3777-3931

Note: [2] https://orcid.org/0000-0002-4087-7822

Note: [3] https://orcid.org/0000-0003-2276-0855

Note: [4] https://orcid.org/0000-0002-2217-1949

Note: [5] https://orcid.org/0000-0001-7467-7215

Note: [6] https://orcid.org/0000-0002-0537-0903

Note: [7] https://orcid.org/0000-0003-0823-7881

Note: [8] https://orcid.org/0000-0002-6938-7747

Abstract: Argan oil (AO) is an appreciated vegetable oil thanks to its high nutritional and cosmetic values. AO extraction technology has evolved to meet the market demand. However artisanal production is still widely practiced. The present study aimed at highlighting the influence of water quality on the physicochemical and sensory properties of artisanally extracted AO. To meet this objective, AO was prepared using various water types namely: well water (AOWW), tap water (AOTW), mineral water (AOMW), distilled water (AODW), and ultra-pure water (AOUW). The obtained AOs were evaluated in terms of routinely measured quality indices: iodine, peroxide, acidity, and anisidine values, UV specific extinction coefficients, refraction index, and moisture content. Chemical composition (fatty acids, sterols content, and tocopherols content) was investigated together with oxidative stability (OS) and sensory properties. As revealed by the statistical test used, water quality impacted significantly mainly on AO chemical composition, OS, and sensory properties. Obtained results of almost studied quality attributes were consistent with the Official Moroccan Norm. The greatest values of saturated and monounsaturated fatty acids were recorded in AOMW and OAWW, respectively, while AOUW together with AOTW displayed the best record of polyunsaturated fatty acids. Moreover, the highest values of tocopherols were found in AOTW and AOUW. AODW and AOUW presented greatest values of sterols content, OS, and shelf life. Likewise, sensory analysis was satisfactory in almost obtained AOs. Principal component analysis confirmed these results and allowed a good separation among AOs especially with sterols and tocopherols. Based on these outcomes, it could be concluded that water quality is an important parameter to consider by AO producers, ultra-pure and distilled water seemed to exert an ameliorative effect on quality, stability, and shelf life of AOs.

Keywords: Argan oil, artisanal extraction, water quality, bioactive compounds, oxidative stability

DOI: 10.3233/MNM-210005

Journal: Mediterranean Journal of Nutrition and Metabolism, vol. 14, no. 4, pp. 383-399, 2021