effect of argan kernel storage conditions on argan oil quality

Research Article

Effect of argan kernel storage conditions on arganoil quality

Hicham Harhar1, Saıd Gharby2, Dominique Guillaume3 and Zoubida Charrouf1*

1 Laboratoire de Chimie des Plantes, Synthese Organique et Bioorganique, Rabat, Morocco2 Laboratoire Controle Qualite, Lesieur-Cristal, Casablanca, Morocco3 CNRS-UMR 6229, URCA, Reims, France

In the present study, we investigated the relationships between storage conditions of argan kernels and argan

oil quality over a 1-year period. Argan kernels were packaged in black or white bags. Kernels in black bags

were stored at room temperature (RT) while kernels in white bags were stored either at RT or at 48C. Quality

parameters periodically monitored over the 12 months were peroxide and acid value, oil yield, moisture

content, UV absorption, and fatty acid composition. Whereas light had no impact on argan oil quality, only

argan kernel storage at 48C allowed a perfect preservation of argan oil quality after 1 year.

Practical applications: In the present study we have established that solar light does not damage argan

kernels in such a way that it could alter argan oil quality, and that argan kernels can be stored for up to

1 year at 48C without alteration of argan oil quality. If stored at RT, argan kernels should be used within

10 months to prepare edible argan oil.

Keywords: Argan nuts / Edible oil / Quality / Storage

Received: December 4, 2009/ Revised: March 4, 2010/ Accepted: April 1, 2010

DOI: 10.1002/ejlt.200900269

1 Introduction

Argan oil was virtually unknown 20 years ago. Today it has

won acclaim all over the world. Not only is edible argan oil

sold in Japanese, Western European, and Northern American

gourmet stores, but cosmetic argan oil was ranked number

one ingredient by Pierce Mattie PR for 2009. Argan oil is

extracted from the kernels contained in argan fruit [1]. Edible

argan oil is obtained from slightly roasted kernels whereas

non-roasted kernels yield cosmetic-grade oil. The argan tree

(Argania spinosa, family Sapotaceae) that provides argan fruit,

is the essential ecological actor [2] around which the sustain-

able development of Southern Morocco is presently based

[3]. Argan tree grows naturally exclusively in Morocco, there-

fore most of argan oil is produced in this country. However,

argan kernels can also be exported. Consequently, some

amount of argan oil is produced out of the boarders of Morocco.

Argan oil is highly appreciated because of its unique

organoleptic properties [4]. It is also prized for its high level

of unsaturated fatty acids: oleic and linoleic acids [5] as

well as in phenols and g-tocopherol [6]. The concomittant

presence of these chemicals is responsible for the cardiopro-

tective and hypocholesterolemic properties of argan oil [7].

Other major pharmacological properties of argan oil are still

regularly reported [8–11]. Noteworthingly, olive, almond,

and argan oil share some similarities: they are all cold-press

oils, they are all produced from a tree fruit, they all contain at

least 80% of unsaturated fatty acids [12, 13], oleic and

linoleic acids are the two main unsaturated fatty acids of each

oil while palmitic and stearic acids are the two main saturated

fatty acids for each oil [12, 13]. Therefore knowledge about

olive oil/tree or almond oil/tree is often extended to argan oil/

tree. This is particularly regretful since argan oil/tree presents

its own specificities. Just to mention a few examples:

(1) whereas almond or olive trees are cultivated, argan trees

grow wild, covering 3200 square miles of the Souss valley and

sunny slopes of the Anti-Atlas mountains, (2) argan tree grows

exclusively in Morocco whereas almond or olive trees are

cultivated in most Mediterranean countries, and (3) whereas

*Additional corresponding author: Zoubida Charrouf,

? e-mail: [email protected]

Correspondence: Dominique Guillaume, CNRS-UMR6229, URCA,

Laboratoire de Chimie Therapeutique, 51 Rue Cognacq Jay, 51100 Reims,

France

E-mail: [email protected]

Fax: þ33-326-918-029

Abbreviations: PV, peroxide value; RT; room temperature

Eur. J. Lipid Sci. Technol. 2010, 112, 915–920 915

� 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.ejlst.com

a single variety of argan tree exists, there are several varieties of

almond tress and hundreds of different varieties of olive trees

inducing large variations in olive oil composition that is known

to depend on an array of factors including: variety of fruit,

region in which the fruit is grown, extraction method, proc-

essing, and storage [14, 15]. The two latter factors also apply to

argan oil. Another specificity of argan oil production is that the

argan forest is one of the poorest part of Morocco. A vast social

program initiated 15 years ago has led to the creation of woman

cooperatives where argan oil is prepared. In these cooperatives,

only oil extraction has been mechanized, hand-malaxing of

argan dough being replaced by endless presses. All initial steps

necessary to prepare argan oil: fruit picking, nut breaking,

kernel collection, have not changed for centuries and are still

manually performed. Therefore, argan fruit is still collected by

frequently donkey-accompanied argan forest dwellers that

stroll the argan forest for days. Later, those argan forest dwell-

ers or cooperative members air-dry then dehull the gathered

argan fruit. Finally, women in the cooperatives break the argan

nuts to afford the argan kernels that are then stored for several

months in large recycled bags until they get roasted and

mechanically pressed to deliver edible argan oil. Such method

provides a full-time job to the women of the cooperatives all

year long.

Either clear or dark fabric bags are used to store argan

kernels depending on their availability and dwellers or coop-

erative habit. Depending on the space available, kernel bag

storage is performed either indoor or outdoor in a semi-

shaded location with uncontrolled temperature conditions.

Edible argan oil is not refined. Raw material quality and

oil processing are two factors known to directly impact non-

refined oil quality [16, 17]. Concerning argan oil processing,

we have recently reported that mechanically pressed kernels

afford an oil of high quality in terms of taste and preservation

whereas goat-peeled fruit yield kernels whose extracted oil

has an unacceptable dietary quality, rapidly develops off-

flavors [18], and has a chemical composition different from

peeled-fruit-derived oil [19]. Influence of raw material quality

still needs to be precisely studied. Possibly, such a study could

lead to define rules for the proper handling of argan kernels.

Because of its high level in unsaturated fatty acids, argan

kernels are prone to oxidation. Well-known factors influenc-

ing the oxidation of kernel fatty acids are principally tempera-

ture [20, 21], light [20], moisture content [22], time: delay

harvest [23] or storage time [24, 25], and storage temperature

[26–28]. Oxidation can affect oil quality and leads to off-

flavor formation resulting in an oil whose sensory quality is

unacceptable to consumers.

The objective of this study was to investigate the effect of

light and storage temperature on argan kernel quality in the

conditions actually used in the cooperatives: the major institu-

tion producing edible argan oil, so far. Moisture content, yield

in oil, oil acidity and peroxide value (PV), UV absorption, and

fatty acid composition were measured over 1 year to determine

the suitability of the kernels to deliver high quality argan oil.

2 Materials and methods

2.1 Materials and experimental design

Argan fruit was collected in Tiout (Taroudant County) in

August 2007. Fruit was air-dried for 3 wk then mechanically

dehulled (SMIR Technotour, Agadir, Morocco). Argan nuts

were manually opened to get the kernels (10 kg). One half of

the kernels was distributed in black cotton bags (25 bags of

200 g of kernels) and remaining kernels were placed in white

cotton bags (same number of bags and amount of kernels).

Twelve of those later and all black cotton bags of kernels were

stored at room temperature (RT) in a semi-shaded location

(average annual temperature 228C, minimum temperature

158C, maximum temperature 358C) whereas 12 white cotton

bags of kernel were stored at 48C. Storage was prolonged for

up to 1 year. To prepare argan oil a fraction of kernels was

ground and argan oil was extracted using a Soxhlet apparatus

and hexane as extraction solvent. Oil was analyzed after 0, 1,

3, 6, 10, and 12 months of storage. Duplicate measurements

were carried out on each of three replicate samples for chemi-

cal analysis.

2.2 Methods

2.2.1 Moisture content

Kernel moisture content was determined by adapting the

AOAC method 934.06 [29] to 5 g of argan kernels and using

a Jouan Quality Systems oven.

2.2.2 Oil yield

Determination of oil yield was performed following the DIN

EN ISO 659 recommendation [30]. Twenty grams of ground

kernels were placed in a Soxhlet apparatus and extracted with

hexane for 8 h. The organic phase was then concentrated

under vacuum and dried for 5 min in an oven at 1058C. After

determination of the extraction yield, the oil was used for the

other analyses.

2.2.3 Physicochemical measurements

Acid and PV, UV light absorption (K270 and K232), and fatty

acid composition were determined by adapting the analytical

methods described in Regulations EC/2568/91 of the

European Union Commission for olive oil [31].

The acid value was determined by titration of a solution of

oil in ethanol with ethanolic KOH and is expressed as percent

of oleic acid.

The PV was determined by iodine titration with a sodium

thiosulfate solution of a solution of oil in isooctane/acetic acid

2:3 that had been left in darkness in the presence of potassium

iodide.

916 H. Harhar et al. Eur. J. Lipid Sci. Technol. 2010, 112, 915–920


K270 and K232 extinction coefficients were measured at

208C in cyclohexane using a CARY 100 Varian UV

spectrometer.

For fatty acid composition determination, the methyl

esters [32] were analyzed on a BPX 70 column

(25 m � 0.25 mm i.d.) using helium as a carrier gas with

a flow rate of 0.8 mL/min [31]. Results are expressed in

percentage of total fatty acids. For the fatty acid determi-

nation, initial oven temperature was set at 1408C, ramp rate

48C/min, final temperature 1708C, injector temperature

3008C, and detector temperature 3008C.

2.3 Statistical analysis

Student’s t-test to evaluate the statistical significance for

independent and variables interactions was performed with

two-tailed t-tests at p ¼ 0.01 and 0.05, respectively. The data

was evaluated using a computer program (Statgraphics,

Rockville, USA).

3 Results and discussion

In woman cooperatives where argan oil is prepared, dark bags

are more frequently used than white bags. In order to dis-

criminate the effect of temperature from the influence of light

on argan kernel quality, we decided to compare the oxidative

behavior of argan kernels stored at RT in black bags to that of

argan kernels stored at the same temperature in white bags

and to that of argan kernels stored at 48C (dark location).

3.1 Moisture content

Edible oleaginous kernel moisture content is an essential

factor that influences oil yield [33] and quality [34].

Moisture content in fresh argan kernels is 3.8% (�0.2)

(Fig. 1). Whereas in argan kernels stored at 48C, the moisture

content did not significantly fluctuate over 1 year and con-

stantly remained below 4%. Storage at uncontrolled tempera-

ture led to a slight increase in kernel moisture level,

independently of the bag color. This value reached 5% after

1 month and then permanently remained between 4.5 and

5% over the studied period. Moisture content elevation

in kernels stored at RT can likely be attributed to the

light-independent trapping of condensation water induced

by temperature fluctuation between night and day, lack of

air circulation in the bags prohibiting the drying of the

kernels.

3.2 Oil yield

Solvent extraction of fresh argan kernels affords argan oil is

about 55% yield [4]. During our study, initial argan oil yield

was found to be 55.6 � 0.5% (Fig. 2). Storage at uncon-

trolled temperature led, over 1 year, to a permanent decrease

in argan oil independently of the bag color. After 12 months

of storage in black or white bag, argan oil extraction yield was

found to be only 51.9 � 0.9%. For argan kernels kept at 48C,

the decrease was much lower during the first month, the yield

of extraction remained above 54 � 0.5% at the end of the

eighth month. After 8 months, oil yield of refrigerated kernels

further decreased rapidly. Finally almost similar oil yields

were observed after 1 year, independently of the light or

temperature storage. For argan kernels stored at RT, the

fastest decrease in oil yield occurred during the first month

of the storage. Interestingly, during this period moisture level

of argan kernels increased suggesting a possible direct corre-

lation between the elevated moisture content and the reduced

amount of extracted oil as already reported for the kernels

of Ricinodendron heudelotii [35]. This could also explain

the oil yield decrease observed for refrigerated kernels after

8 months.

3.2.1 Peroxide value

Lipid oxidation is the major event limiting edible oil shelf life.

It can result from light and/or thermodynamically controlled

processes. High PV is generally associated with fat rancidity

but the PV threshold depends on the fat material. For

example, butter presenting a PV above 2 meq O2/kg also

presents a rancid taste [36] whereas the taste of walnut oils

presenting PV of 0.15 or 6.3 meq O2/kg have both been

judged satisfactory by a trained panel [37]. In most edible

oils, a rancid taste often begins to be noticeable when the PV

is between 20 and 40 meq O2/kg [37]. Changes in PV are

Figure 1. Moisture content in argan kernels stored for 1 year at

room temperature (RT) in white or black bag.

Figure 2. Oil yield from argan kernels stored for 1 year at room

temperature (RT) in white or black bag.

Eur. J. Lipid Sci. Technol. 2010, 112, 915–920 Argan kernel storage and argan oil 917


shown in Fig. 3. The initial PV of fresh argan kernels was very

low (0.15 meq O2/kg argan oil). Storage at uncontrolled

temperature induced large fluctuations of PV evidencing the

formation of secondary decomposition products also suggest-

ing the occurrence of multiple biochemical processes occur-

ring at RT. Interestingly, some of these processes appear to be

light-influenced since the highest PV value was observed for

argan oil coming from argan kernels stored in white bags for 1

year. Differences in PV were also constantly observed during

the study between kernels stored in black or white bag con-

firming the influence of light on the oxidative processes.

Storage at 48C and in the absence of light reduced the

oxidative rate since PV remained virtually constant between

months 1 and 12 (1.7 � 0.3 meq O2/kg argan oil).

3.2.2 Acid value

Acid value is another useful parameter that reflects edible oil

quality[38]. Initial acid value of our argan oil samples was

0.1%. Storage did not induce significant variations in terms

of acid value until the tenth month. Only after 1 year, acid

value of argan oil prepared from kernels stored at RT was

found to be significantly higher than that prepared from

refrigerated kernels (Fig. 4). The similar pattern observed

for kernels stored in black or white bag strongly suggests that

light does not influence acid value variations. Interestingly,

acid value of argan oil prepared from kernels stored at 48Cwas found to be higher than that of argan oil prepared from

kernels stored at RT for 10 months. Such result can be

linked to the increase in moisture content observed after

10 months in kernels stored at 48C (Fig. 1). Therefore,

increased acid value likely results from a water-assisted

hydrolysis of the triacylglycerides.

3.2.3 Specific extinction

Specific extinction can be used to evaluate the presence of

primary (K232) or secondary (K270) oxidation products.

Interestingly, no significant variation of specific extinction

neither at 232 nor at 270 nm was observed during the first

10 months of our study (Fig. 5). After 10 months of storage at

RT, specific extinction at 232 nm increased reflecting the

formation of primary oxidation products in argan kernels.

Again, the similar pattern observed for kernels stored in black

or white bag suggest that light does not influence the specific

extinction.

3.2.4 Fatty acid composition

Argan oil is particularly rich in unsaturated fatty acids. Its

oleic and linoleic acid levels are between 42 and 47%, and

between 31 and 35%, respectively. In addition, argan oil

also contains two saturated fatty acids: palmitic acid (12–

14%) and stearic acid (5–7%) [39]. Our studied oil samples

initially contained 47.2, 30.3, 15.4, and 5.9% of oleic,

linoleic, palmitic, and stearic acid, respectively. No signifi-

cant variation in fatty acid composition was observed for

1 year as a function of the light or temperature conditions

(Table 1).

The results of our study show that acid, PV, and K232

are the major parameters influenced by argan kernel stor-

age and changes principally occur after 10 months of stor-

age at RT. As light does not appear to be an important

parameter altering kernel quality, temperature should be

more carefully monitored since after 10 months of storage

at uncontrolled temperature, argan kernels deliver lower

quantities of an oil of significantly lower quality. Therefore,

unless argan kernels can be refrigerated, argan kernel stor-

age time should be kept up to 10 months. This datum is

particularly important when argan kernels are shipped

overseas and sometimes can stand on docks for long

period of time. In that case, to preserve argan oil quality,

argan kernel foreign purchasers should seriously con-

sidered the use of active packaging [40] since such meth-

odology has recently been shown to be highly efficient to

protect almond kernels [41]. However, for the moment,

such alternative is regrettably not economically applicable

in the argan forest.Figure 4. Acid value of argan oil prepared from argan kernels

stored for 1 year at room temperature (RT) in white or black bag.

Figure 5. Specific extinction (K232, above andK270, below) of argan

oil prepared from argan kernels stored for 1 year at room tempera-

ture (RT) in white or black bag.

Figure 3. Peroxide value of argan oil prepared from argan kernels

stored for 1 year at room temperature (RT) in white or black bag.



We thank M. Chafchaouni (Association Ibn Al Baytar) and

Lesieur Cristal for their interest in this work and financial support,

respectively. This work was realized in the frame of ‘‘Projet

Arganier’’ supported by ‘‘Agence de Developpement Social,

Morocco’’ and the European Economic Community. We are

grateful to the women of the Taitmatine cooperative in Tiout for

sharing observations on argan oil preparation.

The authors have declared no conflict of interest.

References

[1] Charrouf, Z., Guillaume, D., Driouich, A., The argan tree,an asset for Morocco. Biofutur 2002, 220, 54–57 (in French).

[2] Charrouf, Z., Harhar, H., Gharby, S., Guillaume, D.,Enhancing the value of argan oil is the best mean to sustainthe argan grove economy and biodiversity, so far.Oleag. CorpsGras Lipides 2008, 15, 269–271.

[3] Charrouf, Z., Guillaume, D., Sustainable development inNorthern Africa: The argan forest case. Sustainability2009, 1, 1012–1022.

[4] Charrouf, Z., Guillaume, D., Ethnoeconomical, ethnomed-ical, and phytochemical study of Argania spinosa (L.) Skeels.J. Ethnopharmacol. 1999, 67, 7–14.

[5] Charrouf, Z., Guillaume, D., Chemistry of the secondarymetabolites of Argania spinosa (L.) Skeels. Curr. Top.Phytochem. 2002, 5, 99–102.

[6] Charrouf, Z., Guillaume, D., Phenols and polyphenols fromArgania spinosa. Am. J. Food Technol. 2007, 2, 679–683.

[7] Charrouf, Z., Guillaume, D., Argan oil: Occurrence,composition and impact on human health. Eur. J. LipidSci. Technol. 2008, 110, 632–636.

[8] El, F., Babili, J., Bouajila, I., Fouraste, A., et al., Chemicalstudy, antimalarial and antioxidant activities, and cytotox-icity to human breast cancer cells (MCF7) of Argania spinosa.Phytomedicine 2010, 17, 157–160.

[9] Samane, S., Christon, R., Dombrowski, L., Turcotte, S.,et al., Fish oil and argan oil intake differently modulate insulin

resistance and glucose intolerance in a rat model of dietary-induced obesity. Metabolism 2009, 58, 909–919.

[10] Mekhfi, H., Gadi, D., Bnouham, M., Ziyyat, A., et al., Effectof argan oil on platelet aggregation and bleeding time: Abeneficial nutritional property. J. Complement Int. Med.2008, 5, Art. 18.

[11] Bennani, H., Drissi, A., Giton, F., Kheuang, L., et al.,Antiproliferative effect of polyphenols and sterols of virginargan oil on human prostate cancer cell lines. Cancer Detect.Prev. 2007, 31, 64–69.

[12] Dubois, V., Breton, S., Linder, M., Fanni, J., Parmentier,M., Fatty acid profiles of 80 vegetable oils with regard to theirnutritional potential. Eur. J. Lipid Sci. Technol. 2007, 109,710–732.

[13] Kazantzis, I., Nanos, G. D., Stravoulakis, G. G., Effect ofharvest time and storage conditions on almond kernel oil andsugar composition. J. Sci. Food Agric. 2003, 83, 354–359.

[14] Cicerale, S., Conlan, X. A., Sinclair, A. J., Keast, R. S. J.,Chemistry and health of olive phenolics. Crit. Rev. Food Sci.Nutr. 2009, 49, 218–236.

[15] Velasco, J., Dobarganes, C., Oxidative stability of virgin oliveoil. Eur. J. Lipid Sci. Technol. 2002, 104, 661–676.

[16] Cayuela, J. A., Rada, M., Perez-Camino, M., Benaissa, M.,et al., Characterization of artisanally and semiautomaticallyextracted argan oils from Morocco. Eur. J. Lipid Sci. Technol.2008, 110, 1159–1166.

[17] Marfil, R., Cabrera-Vique, C., Gimenez, R., Bouzas, P. R.,et al., Metal content and physicochemical parameters used asquality criteria in virgin argan oil: Influence of the extractionmethod. J. Agric. Food Chem. 2008, 56, 7279–7284.

[18] Matthaus, B., Guillaume, D., Gharby, S., Haddad, A., et al.,Effect of processing on the quality of edible argan oil. FoodChem. 2010, 120, 426–432.

[19] Charrouf, Z., El Hamchi, H., Mallia, S., Licitra, G., et al.,Influence of roasting and seed collection on argan oil odorantcomposition. Nat. Prod. Commun. 2006, 1, 399–404.

[20] Jensen, P. N., Sorensen, G., Engelsen, S. B., Bertwlsen, G.,Evaluation of the quality of walnut kernels (Juglans regia L.)by Vis/NIR spectroscopy. J. Agric. Food Chem. 2001, 49,5790–5796.

Table 1. Fatty acid composition (% W SD) of argan oil from kernels stored for 1 year

Fatty acid Initial Month 1 Month 3 Month 8 Month 10 Month 12

At room temperature in white bags

Oleic acid 47.2 � 1.5 46.4 � 1.5 48.8 � 1.5 47.4 � 1.5 48.1 � 1.5 48.9 � 1.5

Linoleic acid 30.3 � 1.5 29. � 1.51 30.6 � 1.5 31.1 � 1.5 31.3 � 1.5 30.1 � 1.5

Palmitic acid 15.4 � 0.7 13.6 � 0.7 13.7 � 0.7 13.9 � 0.7 13.7 � 0.7 14.1 � 0.7

Stearic acid 5.9 � 0.5 5.9 � 0.5 5.7 � 0.5 6.3 � 0.5 5.8 � 0.5 5.8 � 0.5

At room temperature in black bags

Oleic acid 47.2 � 1.5 46.5 � 1.5 48.3 � 1.5 47.2 � 1.5 48.1 � 1.5 48.6 � 1.5

Linoleic acid 30.3 � 1.5 29.5 � 1.5 31.8 � 1.5 31.4 � 1.5 30.4 � 1.5 30.3 � 1.5

Palmitic acid 15.4 � 0.7 13.8 � 0.7 13.7 � 0.7 13.9 � 0.7 14.6 � 0.7 14 � 0.7

Stearic acid 5.9 � 0.5 5.8 � 0.5 5.7 � 0.5 6.1 � 0.5 5.8 � 0.5 5.8 � 0.5

At 48C in white bags

Oleic acid 47.2 � 1.5 47 � 1.5 48.8 � 1.5 47.8 � 1.5 48.2 � 1.5 48 � 1.5

Linoleic acid 30.3 � 1.5 29.7 � 1.5 30.5 � 1.5 31.5 � 1.5 30.9 � 1.5 30.6 � 1.5

Palmitic acid 15.4 � 0.7 14 � 0.7 13.8 � 0.7 14.1 � 0.7 13.9 � 0.7 14.3 � 0.7

Stearic acid 5.9 � 0.5 6 � 0.5 5.8 � 0.5 6.2 � 0.5 5.8 � 0.5 5.8 � 0.5

Eur. J. Lipid Sci. Technol. 2010, 112, 915–920 Argan kernel storage and argan oil 919


[21] Pastorelli, S., Torr, L., Rodriguez, A., Valzacchi, S., et al.,Solid-phase micro-extraction (SPME-GC) and sensors asrapid methods for monitoring lipid oxidation in nuts. FoodAddit. Contam. 2007, 23, 1236–1241.

[22] Reed, K. A., Sims, C. A., Gorbet, D. W., O’Keefe, S. F.,Storage water activity affects flavor fade in high and normaloleic peanuts. Food Res. Int. 2002, 35, 769–774.

[23] Walton, D. A., Wallace, H. M., Delayed harvest reducesquality of raw and roasted macadamia kernels. J. Sci. FoodAgric. 2009, 89, 221–226.

[24] Garcia-Pascual, P., Mateos, M., Carbonell, V., Salazar,D. M., Influence of storage conditions on the quality ofshelled and roasted almonds.Biosys. Eng. 2003, 87, 201–209.

[25] Mexis, S. F., Badeka, A. V., Riganakos, K. A., Karakostas,K. X., Kontominas, M. G., Effect of packaging and storageconditions on quality of shelled walnuts. Food Control 2009,20, 743–751.

[26] Kazantzis, I., Nanos, G. D., Stravroulakis, G. G., Effectof harvest time and storage conditions on almond kerneloil and sugar composition. J. Sci. Food Agric. 2003, 83,354–359.

[27] Maskan, M., Karatas, S., Storage stability of whole-splitpistachio nuts (Pistachia vera L.) at various conditions.Food Chem. 1999, 66, 227–233.

[28] Lopez, A., Pique, M. T., Romero, A., Aleta, N., Influence ofcold-storage condition on the quality of unshelled walnuts.Int. J. Refrig. 1995, 8, 544–549.

[29] Boland, F. E., AOAC official method 934.06. Moisture indried fruits. in: Cunniff, P. (Ed.), Official Methods of Analysisof AOAC International, 16th Edn, 4th revision, Vol. II. AOACInternational, Gaithersburg, MD 1998, Chapter 37, p. 4.

[30] ISO 659, 1998, Oilseeds – Determination of oil content(Referenz method) – German version EN ISO. 659: 1998.

[31] EC/2568/91. Commission of the European Communities.Regulation 2568/91 on the characteristics of olive oil and

oilve-residue oil and on relevant methods of analysis. Off. J.Eur. Commun. 2003, L-248, 1–109.

[32] ISO 5509, 2000, Corps gras d’origines animale et vegetales –Preparation des esters methyliques.

[33] Cheftel, J. C., Cheftel, H., Introduction a la chimie et a labiochimie des aliments. Vol. 1. Paris (France): 1984,Lavoisier Tec et Doc.

[34] Orthoeffer, F. T., Oil processing and quality assurance. in:Hui, Y. H. (Ed.), Bailey’s Industrial Oil and Fat Products, Vol.4. John Wiley and Sons, Inc., New York, USA 1996.

[35] Tchiegang, C., Aboubakar Dandjouma, A. K., Kapseu, C.,Parmentier, M., Optimisation de l’extraction de l’huile parpressage des amandes de Ricinodendron heudelotii Pierre exPax. J. Food Eng. 2005, 68, 79–87.

[36] Bakirci, I., Celik, S., Ozdemir, C., The effects of commercialstarter culture and storage temperature on the oxidativestability and diacetyl production in butter. Int. J. DairyTechnol. 2002, 55, 177–181.

[37] Vanhanen, L. P., Savage, G. P., The use of peroxide value asa measure of quality for flour stored at five different tem-peratures using three different types of packaging. FoodChem. 2006, 99, 64–69.

[38] Ekwenye, U. N., Chemical characteristics of palm oil bio-deterioration. Biokemistri 2006, 18, 141–149.

[39] Charrouf, Z., Guillaume, D., Secondary metabolites fromArgania spinosa (L.) Skeels. Phytochem. Rev. 2002, 1, 345–354.

[40] Ahvenainen, R., Active and intelligent packaging. in:Ahvenainen, R. (Ed.), Novel Food Packaging Techniques.Woodhead Publishing, CRC Press, Washington, DC, USA2003, pp. 5–13.

[41] Mexis, S. F., Kontominas, M. G., Effect of oxygen absorber,nitrogen flushing, packaging material oxygen transmissionrate and storage conditions on quality retention of raw wholeunpeeled almond kernels (Prunus dulcis). LWT – Food Sci.Technol. 2010, 43, 1–11.



effect of argan kernel storage conditions on argan oil quality

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