Chemical and oxidative properties of olive and argan oils sold on the Moroccan market. A comparative study

Effect of seed's geographical origin on cactus oil physico-chemical characteristics, oxidative stability, and antioxidant activity

The aim of this study was the valorisation of cactus (or prickly pear, Opuntia ficus-indica) seeds growing in six different regions of Morocco. Moisture, proteins, lipids profile, total polyphenols content, oxidative stability, and antioxidant activity were investigated. The Folin-Ciocalteu test highlighted the abundant presence of phenolic compounds (165 to 225 mg EAG/100 g of extract) and a significant antioxidant capacity against DPPH free radicals. The seeds contained protein (7-9.25%) and lipids (2.7-5%). Cactus oil quality indices such as acidity and peroxide value were below 1.2% and 10 mEq.O2/kg, respectively. GC analysis revealed that linoleic and oleic acid percentages ranged from 57.1 to 63.8%, and 13.5 to 18.7%, respectively. Cactus seed oil was rich in tocopherols (500-680 mg/kg) and phytosterols (8000-11,100 mg/kg) with a predominance of γ-tocopherols and β-sitosterol. Triacylglycerols, fatty acids and sterols composition showed small variation depending on the geographical origin, while the individual tocopherol profile was significantly influenced.

Date seeds (Phoenix Dactylifera L.) valorization: chemical composition of lipid fraction

Abstract This research was aimed to study the lipid fraction of date seeds. Seventeen seeds of date palm varieties and clones were evaluated and assessed for their chemical components and for the properties of the date pits oil. Gas liquid chromatography showed that the main unsaturated fatty acid was oleic acid (46.00 - 50.87%), while the main saturated fatty acid was lauric acid (10.11 - 19.03%) for the cultivars Mentouj Tissgharine (MTN) and Bheir Ingli (KBN) respectively; other fatty acids were also identified. The physicochemical characterization showed an acid value ranging from 0.068 to 1.188%, a specific extinction value equal to (K232: 1.350–2.225; K270: 0.318– 0.521), a peroxide value in the interval (1.059–5.618 meq O2/kg) and an iodine value (41.861–59.980 g Iodine/100 g). The pheophytin content of date seed oils was found within the range from 21.855 to 75.685%. The chemical analysis showed that date seed oil can be useful in cosmetic and food products processing.

The Study of the Heterogeneity of the Qualities of Argan Oils and Pomaces from Different Cooperatives in the Essaouira Region (Morocco)

In this study, a comparison of the intra-regional variation in the quality of Argan oil and pomace collected from 12 cooperatives in the Essaouira region (Morocco) during the COVID-19 period was carried out. All studied Argan pomaces together with the extraction solvents showed a significant difference (p ≤ 0.05) in the total phenolic compounds, flavonoids, and tannins contents. The proteins, residual oils, total sugars, and total reducing sugars contents in the collected pomaces vary considerably among cooperatives of origin, with maximum averages of 50.45%; 30.05%; 3.82 milligrams of glucose equivalent per gram of dry matter; and 0.53 milligrams of glucose equivalent per gram of dry matter, respectively. Therefore, it is a very valuable ingredient for livestock feed and some cosmetic products that may contain it. The remaining Argan oil content in the pomace varied significantly among cooperatives, ranging from 8.74 to 30.05%. Pomace from traditional extraction recorded the highest content (30.05%), showing that the artisanal and modern extraction processes are not standardized. The measurements of acidity, peroxide value, specific extinction coefficient at 232 nm and 270 nm, and conjugated dienes were carried out in accordance with Moroccan Standard 08.5.090 in order to qualitatively classify all investigated Argan oils. Accordingly, the analyzed oils were categorized as "extra virgin Argan oil," "fine virgin Argan oil," "ordinary virgin Argan oil," and "lampante virgin Argan oil." Therefore, several factors can explain these variations in quality grades, both endogenous and exogenous. Overall, the variation observed in the obtained result allows us to deduce the most significant variables impacting the quality of Argan products and by-products.

High-Pressure Water Jet System Treatment of Argan Nut Shell and Enzymatic Hydrolysis for Bioethanol Production

Argan nut shell represents the most generated by-product during the process of the extraction of argan oil. For the first time, argan nut shell was characterized and assessed as a new potential feedstock for bioethanol production using a combination of mechanical and enzymatic pretreatment. Argan shell samples were first disintegrated using the Star Burst system, which involves a high-pressure water jet system. Then, the pretreated argan nut shell was subjected to enzymatic hydrolysis using Viscozyme L (30 FBGU/g). Afterwards, the fermentation of the hydrolysate by Saccharomyces cerevisiae was investigated. Argan nut shell, as a feedstock plentiful in carbohydrates, conferred a high yield of saccharification (90%) and an optimal ethanol bioconversion (45.25%) using Viscozyme L (30 FBGU/g) at 2%w/v of argan feedstock.

Chemical Composition and Antimicrobial Activity of Essential Oil of Fruits from Vitex agnus-castus L., Growing in Two Regions in Bulgaria

The chemical composition of Vitex agnus-castus L. (Verbenaceae family) fruits, collected from two regions in Bulgaria (south-central and north-east Bulgaria), was investigated. The content of proteins (5.3-7.4%), carbohydrates (73.9-78.8%), fiber (47.2-49.9%), ash (2.5-3.0%), essential oils (0.5%), and vegetable oil (3.8-5.0%) were identified in the fruits. The composition of the essential oils (EOs) of Vitex fruits from both regions was determined; the main compounds were 1,8-cineole (16.9-18.8%), α-pinene (7.2-16.6%), sabinene (6.7-14.5%), and bicyclogermacrene (7.3-9.0%), but significant differences in the quantitative and qualitative composition of EOs between the regions were found. The EOs of plants from north-east Bulgaria demonstrated antimicrobial activity against the pathogenic species Salmonella abony, Staphylococcus aureus, and Bacillus subtilis, but the Gram-negative bacteria Esсherichia coli and Pseudomonas aeruginosa exhibited resistance to the oil. Linoleic acid predominated in vegetable oil from both regions, followed by oleic acid. β-sitosterol and γ-tocopherol were the main components in the sterol and tocopherol fraction of the lipids. Phosphatidic acids were the main components in the vegetable oil from north-east Bulgaria, while in the vegetable oil from south-central Bulgaria, all phospholipids were found in almost the same quantity. Overall, significant differences were observed in the chemical composition (proteins, carbohydrates, ash and moisture) of the fruits from the two regions of Bulgaria, as well as in the content of the main components of their essential and vegetable oils.

Argan Oil: Chemical Composition, Extraction Process, and Quality Control

Argan oil is considered a relatively international product exported from Morocco, although different companies in Europe and North America distribute argan oil around the globe. Argan oil is non-refined vegetable oil, of the more well-known “virgin oil” type, is produced from the argan tree [Argania spinosa (L.) Skeels]. The argan tree is deemed to be an important forest species from both social and economic standpoints. Argan oil has rapidly emerged as an important product able to bring more income to the local population. In addition, it also has important environmental implications, owing to its ability to stand against desert progression. Currently, argan oil is mainly produced by women's cooperatives in Morocco using a semi-industrial mechanical extraction process. This allows the production of high-quality argan oil. Depending on the method used to prepare argan kernels, two types of argan oil can be obtained: food or cosmetic grade. Cosmetic argan oil is prepared from unroasted kernels, whereas food argan oil is achieved by cold pressing kernels roasted for a few minutes. Previously, the same food argan oil was prepared exclusively by women according to a laborious ancestral process. Extraction technology has been evolved to obtain high-quality argan oil at a large scale. The extraction process and several accompanying parameters can influence the quality, stability, and purity of argan oil. In view of this, the present review discusses different aspects related to argan oil chemical composition along with its nutritional and cosmetic values. Similarly, it details different processes used to prepare argan oil, as well as its quality control, oxidative stability, and authenticity assessment.

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

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.

Discrimination of Geographical Origin of Unroasted Kernels Argan Oil (Argania spinosa (L.) Skeels) Using Tocopherols and Chemometrics

Valorisation of Argan oil requires the precise identification of different provenances markers. The concentration of tocopherol is regarded as one of the essential parameters that certifies the quality and purity of Argan oil. In this study, 39 Argan samples from six different geographical origins (Safi, Essaouira, Agadir, Taroudant, Tiznit, and Sidi Ifni) from the central west of Morocco were collected and extracted using cold pressing. The total tocopherol amount was found to range from 783.23 to 1,271.68 mg/kg. Generally, γ-tocopherol has the highest concentration in Argan oil. It should also be noted that the geographical origin was found to have a strong effect on the amounts of all tocopherol homologues studied. Principal component analysis of tocopherol concentrations highlighted a significant difference between the different provenances. The content of tocopherol has also been found to be strongly influenced by the distance from the coast and altitude, whereas no significant effect was found regarding other ecological parameters. The prediction ability of the LDA models was 87.2%. The highest correct classification was revealed in coastal provenances (100%), and the lowest values were from the continental ones (71.4%). These results provide the basis for determining the geographical origins of Argan oil production with well-defined characteristics to increase the product’s value and the income of local populations. In addition, this study provides a very promising basis for developing Argan varieties with a high content of tocopherol homologues, as well as contributing to the traceability and protection of Argan oil’s geographical indication.

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

Quality control and traceability of Argan oil requires precise chemical characterization considering different provenances. The fatty acid profile is an essential parameter that certifies the quality and purity of Argan oil. In addition, stable isotopes were recently shown to be accurate as an indicator for geographical origin. In this study, fatty acid composition by gas chromatography (GC) and stable isotope ratio by isotope ratio mass spectrometry (IRMS) were investigated for classifying Argan oil according to its geographical origin. Forty-one Argan oil samples, belonging to six geographical origins of Moroccan natural Argan population (Safi, Essaouira, Agadir Ida Outanane, Taroudant, Tiznit and Sidi Ifni) were collected and extracted under the same conditions. The results show that the isotope δ¹³C, palmitic acid (C16:0), linoleic acid (C18:2) and unsaturated fatty acids (UFA) were strongly influenced by ecological parameters. Linear discriminant analysis (LDA) was performed to discriminate the six studied provenances. Discriminant models predicted the origin of Argan oil with 92.70% success. Samples from Safi, Essaouira and Agadir Ida Outanane presented the highest classification rate (100%). In contrast, the lowest rate was reported for samples from Tiznit (85.70%). The findings obtained for fatty acids and isotope combination might be considered as an accurate tool for determining the geographical origins of Argan oil. Moreover, they can potentially be used as specific markers for oils labeled with Protected Geographical Indication (PGI).

Shelf-life of Moroccan prickly pear (Opuntia ficus-indica) and argan (Argania spinosa) oils: a comparative study

Cactus seed oil is gaining considerable popularity in the cosmetic industry. To estimate cactus seed oil’ industrial as well as domestic ease of use, we investigated the oxidative stability of Moroccan cactus seed oil under accelerated aging conditions. In addition, we compared cactus seed oil stability to that of argan oil, a popular and well-established cosmetic oil, under the same conditions. Cactus seed oil is much more sensitive to oxidation than argan oil. Its shelf-life can be estimated to be no longer than 6 months at room temperature. Such instability means that the preparation process for cactus oil must be carried out with great care and cactus seed oil needs to be protected once extracted.

The Triacylglycerol Profile of Oil Bodies and Oil Extracted from Argania spinosa Using the UPLC Along with the Electrospray Ionization Quadrupole-Time-of-Flight Mass Spectrometry (LC-Q-TOF-MS)

The triacylglycerol (TAG) matrix of argan oil (AO) bodies (AOB) along with the TAGs of AO extracted from the same kernels using an organic solvent, were identified and quantified using the ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Generally, both samples showed a similar TAGs profile but AO found to have three extra TAGs in low amount. In total 23 and 26 different TAGs were identified in AOBs and AO, respectively. The most abundant TAGs were OOL, POO, OOO, and POL in both samples. Furthermore, oleic acid, linoleic acid, and palmitic acid were the major fatty acids in both AOBs and AO. To the best of our knowledge, this is the first research that studied the TAGs matrix of an oil body revealing no major difference between the TAGs profile protected by the AOBs membrane and the oil extracted from the whole seed. PRACTICAL APPLICATION: Seed and kernels oil bodies emulsion tend to be the new source of emulsified oil in food and cosmetic industries. However, before replacing a product with another, we have to make sure that the new alternative can offer better or at least similar benefits. Our results showed that the triacylglycerols (TAGs) matrix and the argan oil (AO) share the same TAGs profile with a relatively close percentage. Therefore, AO bodies can be the perfect pre-emulsified oil for some food products like sauces and creams.

The embryo and the endosperm contribute equally to argan seed oil yield but confer distinct lipid features to argan oil

In the perspective of studying lipid biosynthesis in the argan seed, the anatomy, ploidy level and lipid composition of mature seed tissues were investigated using an experimental design including two locations in Algeria and four years of study. Using flow cytometry, we determined that mature argan seeds consist of two well-developed tissues, the embryo and the endosperm. The lipid content of the embryo was higher than that of the endosperm, but the dry weight of the endosperm was higher. Consequently, both tissues contribute equally to seed oil yield. Considerable differences in fatty acid composition were observed between the two tissues. In particular, the endosperm 18:2 percentage was twofold higher than that of the embryo. The tocopherol content of the endosperm was also markedly higher than that of the embryo. In contrast, the endosperm and the embryo had similar sterol and triterpene alcohol contents and compositions.

Argan Oil and Postmenopausal Moroccan Women: Impact on the Vitamin E Profile

Vitamin E supplements could be beneficial for postmenopausal women. To evaluate the effect of edible argan oil consumption on the antioxidant status of postmenopausal women, the vitamin E serum level of 151 menopausal women consuming either olive or argan oil was determined. Serum level of vitamin E was increased in the argan oil consumer group. Therefore, an argan oil-enriched diet can be recommended to help prevent some postmenopausal disorders.