1. F. Mohammed, A. Bouhaouss, R. Bchitou*
INFLUENCE OF THE TRANSFER OF HEAVY METALS AND MICRO-NUTRIMENTS ELEMENTS IN DIFFERENT PARTS OF THE ARGAN TREES : CONTRIBUTION OF CHEMOMETRICS
F. Mohammed, A. Bouhaouss, R. Bchitou*
 Laboratoire de Chimie Physique Générale, Matériaux, Nanomatériaux et Environnement, Département de Chimie, Faculté des Sciences, Université Mohammed V-Agdal, Rabat, Morocco *
Argan oil is a vegetable oil that has recently conquered the world. Argan oil that is prepared by press extraction of argan kernels is a typical Moroccan product, and that is exceptionally rich in essential fatty acids, tocopherols, squalene, phenolic antioxidants and sterols. The argan tree is exclusively endemic in Morocco and is grown in Anti-Atlas mountains, and the coastal region between Essaouira and Agadir. Because of this large distribution, the soil mineral composition of the argan forest undergoes large variation.
However, it implies that all argan samples from the whole argan forest have a similar trace elements composition, independently on the soil metal composition. In this paper, we study the amounts of dietary elements in edible as well as in beauty argan oil prepared from differents locations of the argan forest. The study was performed on a three years period for study the influence of the transfer of heavy metals and micro-nutriments elements in differents parts of argan trees and oil.
Materials and methods
Statistical analysis
Parameters determined in argan oil were studied as statistical variables. Each given value corresponds to the average of three independent measurements. Variability in each parameter and between both oil groups (roasted and unroasted kernels methods) was analyzed. Possible correlations between metals and between metal content and several quality parameters were also studied; P values < 0.05 were considered to be statistically significant. Statistical analysis was performed using the Statigraphics Plus package and SPSS (PCA).
Dietary element amounts in argan oil
Concentration (mean ± standard deviation) in mg kg-1 of evaluted metals in the soil and various parts of argan tree, and in argan
Essaouira
Taroudant
Ait Baha
Agadir
Roasted
Unroasted
2009
Fer
0.77±0.01
0.83±0.01
3.04±0.03
1.61±0.03
0.95±0.005
0.96±0.06
1.55±0.02
1.98±0.03
Potassium
0.42±0.008
0.46±0.006
1.10±0.004
0.49±0.003
0.47±0.003
0.61±0.007
0.52±0.006
Magnésium
4.33±0.06
2.82±0.08
7.62±0.03
2.42±0.08
4.52±0.02
3.61±0.02
5.95±0.06
2.42±0.06
Calcium
7.98±0.01
7.93±0.02
11.1±0.03
3.68±0.09
7.01±0.02
5.02±0.03
11.7±0.03
12.5±0.04
Phosphore
10.66±0.049
7.754±0.016
20.82±0.112
1.637±0.006
12.51±0.022
9.606±0.021
13.41±0.02
5.765±0.037
2010
0.70±0.01
0.74±0.02
0.66±0.008
0.89±0.01
0.35±0.004
0.20±0.004
0.50±0.01
1.18±0.03
0.55±0.003
0.38±0.05
0.78±0.001
0.43±0.001
0.77±0.002
0.69±0.004
0.64±0.003
0.43±0.005
3.57±0.008
3.11±0.004
6.53±0.01
6.47±0.01
3.57±0.02
2.28±0.002
1.35±0.008
1.50±0.03
11.0±0.4
6.84±0.3
11.3±0.08
4.41±0.06
9.01±0.02
8.6±0.02
28.5±0.8
15.3±0.1
8.493±0.008
8.607±0.080
17.790±0.35
1.442±0.006
13.507±0.02
6.74±0.018
0.538±0.005
3.447±0.018
2011
0.98±0.007
0.71±0.02
0.84±0.02
0.82±0.01
0.97±0.004
0.64±0.01
2.28±0.003
2.5±0.05
0.57±0.005
0.39±0.007
1.1±0.01
0.51±0.006
0.48±0.002
0.88±0.001
0.98±0.002
3.06±0.004
2.89±0.01
6.19±0.006
6.32±0.05
4.53±0.01
1.99±0.01
8.54±0.02
0.94±0.001
9.65±0.03
6.94±0.03
9.22±0.03
3.02±0.02
4.83±0.01
11.78±0.03
4.2±0.01
7.884±0.007
6.937±0.084
23.69±0.279
1.194±0.017
12.517±0.022
5.399±0.033
26.40±0.059
3.273±0.32
Location
Sample Cd Cr Cu Pb Zn Ca P K Mg
Essaouira
Soil
0.8±0.02
3.1±0.4
160.2±2.6
278.2±2.9
87.2±2.73
1700±18.0
2027±19
47348±27
9808±23
Wood
0.1±0.01
20.8±1
5.8±0.7
22.0±1.1
14.4±1.0
89800±31
560±9
8343±24
1665±17
Leaves
0.2±0.01
3.9±0.7
4.6±0.4
5.2±0.6
16.7±0.9
19300±27
807±13
5374±23
3532±22
Almonds
1.7±0.04
4.8±0.5
2.4±0.08
5.6±0.7
2500±18.3
166±2
3545±22
4567±23
Oil
0.4±0.02
85.7±2.7
31.3±1.5
8.7±0.8
80.3±2.6
398±7
2174±19
354±7
593±7
AitBaha
0.8±0.03
3.5±0.4
224±3
36.4±1.5
109.3±2.8
1900±18
2550±19
49533±27
9495±24
28±1.5
8.5±0.8
25.6±1.2
20.9±1.0
107900±33
867±13
18374±25
706±13
4.1±0.5
3.8±0.4
17.2±0.9
18600±25
873±13
6930±23
2223±19
0.6±0.02
4.0±0.5
16.7±1.0
19.7±1.0
12200±26
698±9
4890±23
2345±19
0.7±0.02
80.4±2.6
40.4±1.7
15.7±1.0
86.7±2.7
687±9
1879±18
877±13
498±7
Tiznit
0.5±0.03
5.7±0.7
140.6±2.2
28.3±1.4
82.0±2.7
5500±23
2633±21
44331±23
5545±23
0.02±0.01
0.05±0.01
75.6±2.5
18.4±1.0
±31
2987±22
11190±25
1283±14
1.8±0.05
1.0±0.02
70.5±2.5
±37
1892±18
18852±26
1787±18
1.3±0.04
2.7±0.09
77.6±2.6
54.5±1.7
±35
2851±22
14356±25
1578±16
1.5±0.04
75.3±2.5
37.4±1.5
13.7±0.9
60.7±2.1
469.8±7.2
789±13
376±7
Taroudant
1.1±0.03
80.8±2.6
9.5±0.8
±34
3000±22
50144±27
8087±23
1.2±0.04
63.7±2.2
13.8±0.9
929150±30
8664±24
1500±16
1.0±0.03
1.5±0.06
58.8±1.7
21.7±1
±35
2589±18
7502±23
2283±19
1.6±0.06
0.2±0.02
81.8±2.6
10.0±0.8
±37
1235±14
5678±23
2370±19
1.9±0.02
77.2±2.5
46.4±1.8
18.7±1
82.7±2.7
598.54±7.45
1987±18
435±7
74.5±2.5
Agadir
2.2±0.08
66.2±2.1
11.2±0.9
±35
4125±23
51659±27
7376±30
1.8±0.02
99.6±2.8
8.2±0.8
±39
6548±23
8851±24
786±1
2.6±0.09
68.8±2.1
10.6±0.9
±38
7598±23
8436±23
840±13
Amonds
0.5±0.02
80.4±2.7
±39
8568±24
9876±24
4087±22
0.6±0.01
40.1±1.6
28.5±1.4
7.7±0.8
690.67±9.1
558±9
86.5±2.7
Physico-chemical parameters of argan oil prepared from raosted and unroasted kernels
Essaouira
Taroudant
Ait Baha
Agadir
Roasted
Unroasted
2009
Aciditya
0.54±0.03
0.31±0.01
0.36±0.04
0.34±0.02
0.27±0.02
0.43±0.04
0.39±0.02
0.29±0.01
Peroxide valuea
1.7±0.3
2.1±0.2
2.9±0.4
2.7±0.5
1.9±0.2
1.3±0.5
2.8±0.5
1.85±0.5
K232
1.01±0.02
1.35±0.01
1.52±0.04
1.36±0.02
1.29±0.01
1.17±0.03
1.73±0.01
1.69±0.02
K270
0.26±0.06
0.24±0.04
0.25±0.02
0.29±0.05
0.25±0.03
0.22±0.01
0.18±0.06
0.20±0.01
2010
0.3±0.01
0.28±0.03
0.2±0.04
0.54±0.04
0.23±0.01
0.31±0.02
0.33±0.01
0.49±0.01
2.2±0.4
2.4±0.2
1.2±0.4
2.7±0.3
3.1±0.4
1.3±0.2
2.0±0.5
2.9±0.5
1.21±0.01
1.23±0.03
1.17±0.07
1.23±0.01
1.41±0.06
1.20±0.01
1.67±0.06
1.95±0.05
0.16±0.05
0.21±0.01
0.19±0.02
0.23±0.02
0.27±0.06
0.27±0.08
2011
0.26±0.02
0.34±0.04
0.26±0.01
0.35±0.05
0.25±0.05
0.39±0.01
1.2±0.3
1.1±0.2
0.98±0.2
1.7±0.5
2.5±0.5
1.19±0.04
1.25±0.03
1.26±0.09
1.38±0.01
1.93±0.01
2.25±0.05
0.18±0.02
0.25±0.01
0.29±0.06
0.18±0.05
0.20±0.06
Plot in the Dim1×Dim2 plane of PCA of trace element content of argan trees
Plot in the Dim3×Dim4 plane of PCA of trace element content of argan trees
Results and Discussion : Due to the argan forest large size, its soil metal content is inherently location dependent. Sometimes, such variability also possibly results from sewage, insufficient sanitary conditions, strong erosion, and possibly metal accumulation in natural pits favored by low rainfall. Therefore, we evaluated the dietary elements content of argan oil produced in the four main argan oil production sites of the argan forest: Agadir, Ait Baha, Essaouira, and Taroudant. Prior to metal content analysis, we determined the initial quality of all samples. All of them were prepared using the state of the art half mechanized method that is known to produce high quality oil and reproducible metal content. Evaluated physical-chemical parameters were: acid and peroxide value, and specific extinction at 270 nm (K270) and 232 nm (K232). Primary treatment results showed that the RV coefficients of wood, leaves, almonds and oil are relatively higher. The soil group is less correlated with the other four groups. Models based on principal component analysis (PCA) and application of chemometrical methods to micropollutants analysis were used for discrimination between samples as a function of the tree varieties and cultivation zone.
Conclusion : The soil particles explained most of the element distribution pattern in Argan trees, but strong indications for some effects of local sources of some pollutants were detected. The results of this work establish that the reduced fluctuation of the dietary elements content as a function of the location of growth and year of production should permit to suggest inductively coupled plasma emission spectrometry as a possible method to detect or confirm some specific adulteration in edible or beauty argan oil.
References
-Mohammed F., Bchitou R., Nachid N., Bouhaouss A., (2011). Effects of phosphoric acid, cadmium and chromium on the growth of Argan trees. Journal of Physical and Chemical News, 57,
-Mohammed F., Bchitou R., Roger, J.M., Bouhaouss,A. , Palagos B., (2011). Modeling and optimization of relocation of some heavy metals and micro-nutrients in the argan trees. Journal of Chemistry and Chemical Engineering, 5,
-Mohammed F., Bchitou R., Bouhaous A, Garby S., Harhar H ., Guillaume D. , Charrouf Z. , (2012). Can the dietary element content of virgin argan oils really be used for adulteration detection? Food Chemistry ,
7th
"7th European Conference on Pesticides and Related Organic Micropollutants in the Environment and the 13th Symposium on Chemistry and Fate of Modern Pesticides”  Porto-Portugal , 7-10th of October, 2012.