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Der Pharmacia Lettre, 2015, 7 (12):255-264

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ISSN 0975-5071

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Survey of the conservation of medicinal leaves by convective drying multi conditioned

Abdenbi Asma1, Bouaaza Mohammed2, Touati Boumediene1 and Saad Amel1

1Laboratory of Energetic in Arid Zones ENERGARID, University of Bechar, Algeria 2Laboratory of Ecology & Management of Natural Ecosystems, University of Tlemcen, Algeria

_____________________________________________________________________________________________ ABSTRACT The drying consists in decreasing the activity of the water of the dry products until a value assuring their conservation. The process must respect some criterias of quality bound to the product while guaranteeing, for the chain of production, a cadence and a reasonable cost. Several methods exist for the dehydration of the agricultural products. However the drying by convection, named also by practice, stay the most widespread technique and the more used. The conditions of the convective drying that grant the most elevated output rate in extracts aqueous of the leaves of Pistacia atlantica are the temperature 40°C and the debit of air 2.5 m3/s, while preserving meaningful manner the color of the leaves of Pistaciaatlantica, the aerothermicconditions must be maintained respectively to them (T°=40°C for D=1 m3/s) and (T°=50°C for D=1 m3/s). An increase of the content in free sugars is noted after convectivedrying of Pistacia atlanticaleaves, as well as the leaves dried to 50°C / 1.5 m3/s records the best concentration in total sugars (129.29 mg/l) in relation to the leaves dried to other conditions. Key words: Pistaciaatlanticaleaves;convective drying; pigment and sugar free content. _____________________________________________________________________________________________

INTRODUCTION

The natural substances descended of the plants have multiple interests put to profit in the industry: in food, in cosmetology and in dermopharmacy. The Pharmacy uses a strong proportion of medicines of plant origin again [1]. The drying is thus as being the most historic conservation method ", the easiest, the most efficient, the most economic and, again today, the more used. On the one hand, the conservation and the storage of a product dried are generally achieved to positive temperature (ambient or in a system of refrigeration); on the other hand, the molecules dehydrated private of water, are often steadier than the humid molecules. Finally, the reduction of weight (and often of volume) of the dry products facilitates their manipulation, their transportation and their storage. The drying is defined like a reduction of the humidity of the food matter to increase the strong concentration reducing the possibilities of deterioration of various origins thus of it (microbial, enzymatic, oxidization of lipids, chemical reactions…), while preserving as much that possible the physical and chemical features. The specificity of the drying resides in the reduction of the global level of humidity through the evaporation of water with, generally, for objective to reach a level of water activity permitting the complete preservation of the product in question. The conditions of storage of the products dried can have an impact as a matter of course on the quality of the final product. Generally, for the agroalimentary products, the quality of the product finished dried rests on his/her/its color, his/her/its texture, his/her/its aroma and his/her/its content in free sugars. He/it proves to be therefore necessary to study the impact of drying on the content of sugars free of the leaves of the Pistacia atlantica. At the time of the process of the prolonged drying, the color and the content in sugars are damaged especially. However, the solar drying of some agricultural products can entail the deterioration of the color and the ascorbic

Abdenbi Asma et al Der Pharmacia Lettre, 2015, 7 (12):255-264 ______________________________________________________________________________


acid on the one hand and on the other hand the increase of the output in essential oils and in sugars[2] ; [3] ; [4] ; [5] et [6]. Among the pigments implied in the photosynthesis are the chlorophylls has and b as well as the carotenes. These are the lipophilic molecules that specifically absorb light to some lengths of wave. In the setting of the valorization of the Atlantics pistachioof which its local use in therapeutic traditional in the region of Bechar, as antiseptic, antifungal and for the abdominal illnesses. We conducted an aqueous extraction of Pistacia atlanticaleaves, before and after convective drying done to different temperatures. The main objective of this work is therefore to study the impact of convective drying of Pistacia atlantica leaves on the color, the content in total sugars. We also study the impact of the drying on the aqueous present excerpts in these leaves; we compare the effect of convective drying with the effect of drying to the shade.

MATERIALS AND METHODS

2.1 Sampling The atlantics pistachio (Pistacia atlantica) used in this study is located in the south west of Algeria (Bechar), in order to achieve a meaningful withdrawal, the sampling of the leaves takes place in an uncertain way on every quoted of the tree.The leaves ofPistaciaatlanticaare harvestedduring March 2012.Whole leaves of Pistacia atlantica were collected from the field on the day of harvest. 2.2 Drying by convection (training) Gas used in the drier is the hot air whose thermophysicalpropertiesallows him to be had the time a fluid coolant and a vector of water elimination evaporated. In this drying, the convection is the fashion of major transfer. Other fashions of thermal transfer can be added of it however. The conduction by the hurdles supporting the product and the radiance by the partitions of the drier represents the other fashions of contribution of this latent heat of spraying. If one places a humid body in a surrounding wall or reign a hot and dry sparkling flux, differences of temperature and partial pressure of water will be noted thus between the body and the bordering gas to the following phenomena: - A transfer of gas heat toward the humid body under the effect of the existence of a temperature gradient, - A transfer of matter (water) taking place of the body toward gas under the effect of a partial pressure gradient. At the time of the drying by convection, the heat necessary to the drying is transmitted to matter to dry by convection, by a gas in movement. The drier used in this survey is of type « GUNT Hamburg CE130 »,whose constituent elements areshown in figure 1, With: 1: Menu strips; in the menu strip, miscellaneous attitudes can perform and are executed actions. Some of it is available in all program modules, as for example "? ". Over the menu point of "processing", one reaches to the option "TARE" this option puts the value of the scales on zero. 2: Ads: Most system values are passed out over numerical ads.

Figure.1. Diagram system of convective dryer(ENERGARID laboratory)



3: Graphic ads: speed air and temperature air 4: Fan 5: Stoker indicator 6: Dry chamber or drying plate 7: Heater; if the temperature rises at the stoker on over 100 °C, the temperature guard is caused. A corresponding warning is shown in the system diagram at this place. In the adjustable-speed operation, this ad is not visible. 2.3 Water content The content in water of a hygroscopic material or the absolute humidity is defined by the quantity of water contained in a product, expressed in percentage of the dry mass of this product. This value is important for all products sold to the weight.

Xeq = Mh –Ms / Ms

With: Xeq: content in water of balance (% MS) Ms: dry mass (kg) Mh: humid mass (kg). The water contents of the leaves of atlanticspistachio (Pistacia atlantica) have been determined before and after drying. 2.4 Preparation of aqueousExtracts The raw extracts have been gotten by maceration with the distilled water: 20 g of plant material has been extracted with 300 ml of distilled water, by maceration under magnetic agitation during 24 hs. After cooling the solution is filtered, then the filtrate passed in it burp-steam until the total elimination of the present water molecules in this filtrate; one gets the aqueous extract that can be kept to 40C to the refrigerator for the ulterior tests. This method of extraction led to ambient temperature permits to extract the maximum of compounds and to warn their denaturation or likely modification due to the elevated temperatures used in other methods of extraction. Ten different aqueous extracts have been prepared(figure 2): -One extract from Pistaciaatlanticaleaves dried to the shade to ambient temperature (280C) during 10 days, -Nine extracts from Pistacia atlanticaleaves dried to different temperatures (40, 50 and 600C) to different debits of air (1, 1.5 and 2.5 m3/s) with the help of the convective drier (fig 2), The output extracts of it aqueous ofPistacia atlanticaleaves, is calculated while using the following formula: With: P1: weight of the full ball P0: weight of the empty ball P2: the trial hold 2.5 Extraction of the pigments A part of the leaves of Pistacia atlantica has been dried to the shade (temperature and air ambient) and another part of the leaves has been dried in the drier convective in different conditions of air drying (temperature and debit of air) in order to value the rate of pigmentation in the different conditions of drying.

R=��

�� .100

Figure.2. Different extracts gotten of Pistaciaatlantica



To grind 3 g of leaves of Pistacia atlantica finely in a mortar containing a pinch of sand and a pinch of calcium carbonate to neutralize the acidity of the middle. To grind carefully to the pestle until the whole formsdough. The products ground previously to add 20 ml of acetone then under magnetic agitation during 24 hs, to ambient temperature and to the obscurity. The extract of chlorophyll is let decant (funnel + Filter), filtered then adjusted then to 50 ml with a mixture of acetone and water (80/20, v/v) [7]. Three tests are done by sample to assure the reproducibility of the experienceas shown in figure 3. 2.6 Dosage of the total pigments The determination of the optic density is achieved with the help of a spectrophotometer marks: SPECORD 50 MORE - 232H1066, of the absorption specter for the major pigments,: does chlorophyll have and b chlorophyll and? carotene shows a maximal absorbance in the bruise to the lengths of respective waves 460, 645 and 663 nm [5]. To measure out by spectrométrie of absorption, the chlorophylls have and b as well as the present caroténoïdes in the excerpts. - To place a vat in glass, that contains the solvent of extraction, in the bundle and to adjust the zero of the device to 460 nm. To replace this vat by an another one that is filled at 2/3 by the dilute pigmentary excerpt and to read the absorption (A). - To restart the operations successively to 645 nm and 663 nm. To adjust the zero of the device for every length of wave used. The incidental luminous ray (I0) undergoes an attenuation while crossing an absorbing solution of concentration (C).According to the law of Beer-Lambert, the optic density (DO) or the absorbance (A) is defined as follows:

010

IA = DO = log l C

Iε=

Where(��is the coefficient of characteristic molar extinction of the substance studied to a length of wave given in l soft 1 cm 1, (l) the thickness crossed in cm and C the concentration in mol.l-1. - To express the results in mg of cool matter pigments/g and to conclude [7]. Three tests are done by sample to assure the reproducibility of the experience. 2.7 Dosage of the total sugars The dosage of the total sugars containing in the leaves of Pistacia atlantica, is achieved according to the Method of Dubois, 1956, ten samples were doses (figure 3); the first sample represents the leaves of Pistacia atlantica dried to the shade (ambient temperature 28°C), and the nine samples are dried differently with the help of the drier convective (temperatures and debits of different air).

RESULTS AND DISCUSSION 3.1 water content The table1 present the difference in water content ofPistaciaatlantica leaves fresh, dried in shade and after convective drying, noticing the water content is increasing during the drying process.

Table.1. water contents of Pistaciaatlantica leaves before and after drying

Sample Fresh 1 2 3 4 5 6 7 8 9 10 Water content (%db) 0.43 0.23 0.0684 0.0543 0.0228 0.045 0.0509 0.0071 0.0191 0.0048 0.0160

Figure.3. Acetone Chlorophyll extracts ready to measure out



3.2 Times drying The table 2presents the different lengths of drying of the leaves of Pistaciaatlantica to the shade and to the drier convective; we can notice the variation of time according to the temperature and the speed of air drying. More the temperature and the speed of air drying increase, more the length of drying decreases; - To 40°C: the length of drying varies according to the debit of air of 6h to 11h - To 50°C: the length of drying varies according to the debit of air of 6h to 7h - To 60°C: the length of drying varies according to the debit of air of 4h to 5h The drying of Pistaciaatlantica leaves to the shade lasts 10 days, what is longer in relation to the drying with the help of a convective drier.

Table.2. Drying times sheets of Pistaciaatlantica in the shade and convective dryer

Temperatures Ambient (~28°C) 40°C 50°C 60°C Air Debits (m3/s) / 1 1.5 2.5 1 1.5 2.5 1 1.5 2.5

Drying time (hours) 10 days 11 8 6 7 6 6 5 4 4

3.1Extractsproduction The present table2 the results of the excerpts gotten by steeping of the leaves of Pistacia atlantica; in a first time we leave from the leaves that are dried to the shade that wants to tell temperature (290C) and air ambient; these are the conditions used by the local population, and in a second place we study the leaves that are dried with the help of a drier convective; according to three different temperatures (40, 50 and 600C) and three different air debits (1, 1.5 and 2.5 m3/s). The result of the different outputs of the ten aqueous excerpts is summarized in the table 3.

Table.3.Yields aqueous extracts of dried leaves in different conditions

Extrait T0C/ V m3/h Aspect Pourcentage (%) 1 Air ambient Paste, olive green 42.6(%) 2 40 0C/ 1 m3/s Sticky wax, dark green 60.2(%) 3 40 0C/ 1.5 m3/s Sticky wax, dark green 71.15(%) 4 40 0C/ 2.5 m3/s Sticky wax, dark green 75.9(%) 5 50 0C/ 1 m3/s Sticky wax, dark green 57.25(%) 6 50 0C/ 1.5 m3/s Sticky wax, dark green 63(%) 7 50 0C/ 2.5 m3/s Sticky wax, dark green 61.85(%) 8 60 0C/ 1 m3/s Sticky wax, dark green 56.6(%) 9 60 0C/ 1.5 m3/s Sticky wax, dark green 59.75 (%) 10 60 0C/ 2.5 m3/s Sticky wax, dark green 46.8(%)

Noticing the rate of output extracts of it aqueous varies 42.6% until 75.9%. It is difficult to compare the results with those of the bibliography, the output is only relative and depends on the method and conditions in which the extraction has been done. The method of extraction also affects the whole total content in phenol and flavonoids and the activity antioxidant [8]. The extract1, of which the leaves of Pistacia atlantica have been dried in a classic way to the shade, has a color green olive, its consistence looks like a dough mole, its output (42.6%) is the weakest in relation to the other outputs presenting an unique aspect, their texture looks like a sticky wax of dark green color. - To 40°C; the output aqueous extracts intensifies with the increase of the drying speed, it reaches its maximum: 75.9% with 2.5 m3/s (extract 4). - To 50°C; the output aqueous extracts, is decreased itself in relation to the outputs of extraction to 40°C, it reaches its maximum: 63% with 1.5 m3/s (extract 6). - To 60°C; the output aqueous extracts, is decreased itself again in relation to the outputs of extraction to 40°C and 50°C, it succeeds to its maximum: 59.75% with 2.5 m3/s (extract 10). Recording the gotten most elevated output rate, is from the leaves of Pistacia atlantica dried to 40°C to a speed of drying equal to 2.5 m3/s. To this temperature more the debit of air drying increases the rate of output more increases and more the temperature increases, more the output decreases until 46.8%, but it remains always superior in relation to the conditions of drying to the shade (42.6%). This reduction can be explained by the fact that the drying provokes transformations oxidative of the organic compounds dragging a browning of the cloths of the plants that can influence on the quality of the food products. Also noting the output of aqueous extracts of Pistacia atlanticaleaves increases after the drying to 40°C for the debit 2.5 m3/s. This result is probably owed to the resistance to the diffusion through the cellular cloths, that comes on the



one hand from the load in water of the plant and on the other hand of the presence of substances non fowls having an elevated boiling point (as an example the fatty acids) that reduce the speed of spraying [9]. 3.2 Effect of the drying on the color of Pistacia atlanticaleaves The color of the plants is due to the pigments localized in the plasmids, the vacuoles or the liquid cytoplasmic of the cells and sometimes solely of the epidermal cells. Among the principal pigments; the chlorophylls and the carotene. The evolution of the color before and after drying to different temperatures and debits are illustrated respectively in the figure 4.

..

. The figure 4present the evolution of the optic density of the chlorophyll a, b and carotene in the leaves of Pistacia atlantica according to the length of wave to different temperatures (40, 50 and 60°C) and to a constant air debit. The analysis of this face shows that for a constant air debit, the optic density of the chlorophyll a, b pigments decreases while the content carotene of the leaves of Pistacia atlantica increases. Some similar results have been gotten in various works concerning the drying of the medicinal plants [10]; [3]; [6]. Noting for the drying of the leaves of Pistacia atlantica to the shade (ambient temperature): - Debit = 1 m3/s: The curve of the evolution of the pigments analyzed to the shade, is situated between the curves (50°C) and (60°C). - Debit = 1.5 m3/s: The curve of the evolution of the pigments analyzed to the shade, is nearly superimposed on the curve (40°C). - Debit = 2.5 m3/s: The curves of evolution of the pigments analyzed to different temperatures (40, 50 and 600C), are below the curve tested to the shade.

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Figure.4. Evolution of the optic density of the chlorophyll a, b and carotene in Pistaciaatlantica according to the length of wave to different temperatures and to a constant debit. A: Debit= 1 m3/s, B: Debit=1.5m3/s, C: Debit=2.5m3/s

4.C



.

. For a constant temperature (figure 5), the influence of air debit on the content in present total pigments in the leaves of Pistacia atlantica is meaningful, the optic density of the chlorophylls a,b decreases and the content of carotene of Pistacia atlantica leaves increases when the debit of air increases. The pigments content (chlorophyll a, b and B-carotene) of Pistacia atlantica leaves dried with 40°C with a debit of air=1m3/s is important in relation to the pigments content of Pistacia atlanticaleaves dried to the shade and 50°C or 60°C with the same debit of air. The pigments content (chlorophyll a, b and carotene) of Pistacia atlanticaleaves dried to 40°C with a debit of air=1.5m3/s is less important in relation to the pigments content of Pistacia atlanticaleaves dried to 40°C with a debit of air=1m3/s, and is nearly similar to the content in pigments of the leaves dried to the shade. The content in pigments (chlorophyll a, b and carotene) of Pistacia atlantica leaves dried to 40, 50 and 60°C to 2.5m3/s are less important in relation to the content in pigments of Pistacia atlantica leaves dried to the shade. This deterioration is probably owed to the big speed of air drying, more this speed increases the deterioration of the pigments more increases. The deterioration of the pigments to the shade is more important in relation to the temperatures: 40 and 50°C for a speed of air equal to 1 m3/s. This lowering in the total pigments is possibly to the length of drying; who is longer to the shade that to the convective drier, as it is indicated in the figure 4. We recorded that the best condition of convective drying to keep the content in pigments (chlorophyll a, b and carotene) of the leaves of Pistacia atlantica it is to dry to 40°C and 50°C to 1m3/s. The deterioration of the chlorophyll pigments induced a modification of the color of the Pistacia atlantica leaves. This modification is probably owed to the reactions of oxidization during the drying freeing the water that provokes a partial downfall of the spaces intracellular. The pigments are thus salted out of the complex of proteins and the

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Figure.5. Evolution of the optic density of the chlorophyll a, b and carotene in Pistaciaatlantica according to the length of wave to different debits of air to a constant temperature.A: 40°C, B: 50°C, C: 60°C



chloroplasts become more permeable encouraging the liberation of the present acids in the plant while transforming the chlorophyll in phéophytes. This deterioration can also be assigned to the removal of the pigments carotenes that confirms the increase of the content of carotene of Pistaciaatlanticaleaves. It is the role that the drying plays by convection, while transferring the heat of air towardPistacia atlanticaleaves of under the effect of the existence of a temperature gradient, what permits to dry the leaves more quickly in relation to the drying to the shade. The figure 6 presenting an analysis of the specters of absorption of the Pistaciaatlantica dried to the shade and the drier according to different temperatures (40, 50 and 60°C) with debits of different air; the specters have the same pace. On the other hand, we cannot affirm that there was not enormous deterioration of the total pigments of the Pistaciaatlantica.

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A l’ombre

Figure.6. Absorption spectrum of the pigments present in the leaves of Pistaciaatlantica dried at different conditions (temperature and airflow)



3.3 Effect of the drying on the composition in sugars of Pistacia atlantica The contents in sugars free present totals in Pistacia atlanticaleaves dried to the shade and the convective drier to different temperatures vary 70,2 and 129,29 mg/l respectively. The figure 7, represent the variations of concentration in total sugars of dried different leaves.

1 : 28°C/ air ambient 2 : 40 0C/ 1 m3/s 3 : 40 0C/ 1.5 m3/s4 : 40 0C/ 2.5 m3/s5 : 50 0C/ 1 m3/s 6 : 50 0C/ 1.5 m3/s7: 50 0C/ 2.5 m3/s8 : 60 0C/ 1 m3/s9 : 60 0C/ 1.5 m3/s 10 : 60 0C/ 2.5 m3/s

Noticing the percentages of the total sugars of Pistacia atlantica leaves is increased after the drying by contribution to the leaves dried to the shade, and that this content in total sugars has been doubled after drying: -To 40°C: the sample 3 increase nearly to30% (99.143mg/l) in relation to the sample 1(72.73g/l) - To 50°C: the sample 6 increase nearly to45% (129.29mg/l) in relation to the sample 1 - To 60°C: the sample 9 increase nearly to 40% (118.34mg/l) in relation to the sample 1 For the three temperatures (40, 50 and 60°C); the most elevated concentration in total sugars of Pistacia atlantica leaves coincides himself with the speed of air drying equaling 1.5 m3/s. The leaves of Pistacia atlantica dried to 50°C with 1.5 m3/s(sample 6) record the best concentration in total sugars (129.29 mg/l) in relation to the leaves dried to other conditions, even in relation to the drying to the shade (72.73 mg/l). This result is in agreement with other results gotten by Lahsasni (2004) on the drying of the components of the cactus and Al Hodali (1997) for the drying of the apricot. According to (ARHAB R., 2007), the content in total sugars varies according to the climate, the season and the stage of development of the plants, has title of example, the elevated temperatures and the weak precipitations offer to increase the parietal fraction and to decrease the soluble content of the plants [11]. The survey of the impact of the convectivedrying ofPistacia atlanticaleaves on the content in free sugars, allowednoting that the content in free sugars is increased after drying. This rise is probably owed to the reactions of thermolysis or to the reactions of thermoxydativesof their polymers. On the other hand, the increase of the content in total free sugars after convective drying permits to improve the nourishing values and shopkeepers of the product dried.

CONCLUSION

The aerothermicconditionsof the convective drying that grants the most elevated output rate in aqueous extracts of Pistacia atlanticaleaves are the temperature 40°C and the debit of air 2.5 m3/s. This result is probably owed to the resistance to the diffusion through the cellular cloths, that comes on the one hand from the load in water of the plant and on the other hand of the presence of substances non fowls having an elevated boiling point that reduces the speed of spraying. The aerothermicconditions of the convective drying that preserves meaningful manner the color of Pistacia atlanticaleaves is respectively the couples (T°=40°C and for D=1 m3/s) and (T°=50°C and for D=1 m3/s) because

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Figure.7. Variation of the content in sugars of Pistaciaatlanticaleaves dried to different conditions of drying



less one provides energy to the system, less the reactions of deterioration have the time to develop themselves (Lahsasni, 2004). The impact of the convective drying on the content in sugars free of the leaves of Pistacia atlantica is studied. An increase of the content in free sugars is noted. Also illustrating that the drying decreases the content in water of the plant, while weakening the existing links between the secondary metabolites and the cloth of the plant material. More the debit of air drying is weak more the time of contact air/product is prolonged, what drives to the apparition of the phenomena of microdistillation, of the reactions of decomposition and hydrodiffusion that provoke some losses thereafter in secondary metabolites. One has an increase of the output therefore extracts of it aqueous with the increase of the air debit drying. Thus, the convective drying (40°C /1 m3/s, 50°C /1 m3/s and 50°C /1.5 m3/s) is a way of valorization ofPistacia atlanticaleaves in term of value bargains considering the important contents in free sugars and total pigments.

REFERENCES

[1]Bahorun. T, 1997.Substances naturelles actives : La flore mauricienne, une source d'approvisionnement potentielle, Food and Agricultural Research, pages 83 - 94. [2]Al Hodali, R. 1997. Numerical simulation of an agricultural foodstuffs drying unit using solar energy and adsorption process.PhDthesis, Universite Libre de Bruxelles, Belgium, 3aB. [3]Kouhila M., Lahsasni, S., Mahrouz, M., Jaouhari J.T. 2003. Journal of Food Engineering,Vol.6, 173-179. [4]Krokida, M.K.; Maroulis, Z.B.; Marinos-Kouris, D. Drying Technology, v.16, n.3-5, p.687-703, 1998. [5]Lahsasni, S., Kouhila, M., Mahrouz, M., Idlimam, A., Jamali, A. 2004. Energy, Vol. 29, 211-224. [6]Negi, P. S., & Roy, S. K. 2000. Food Science and Technology, 33, 295e298. [7]Kouhila, M., Kechaou, N., Otmani, M., Fliyou, M., &Lahsasni, S.. Drying Technology, 20. 2002. 2027–2039. [8]Lee K. W., Kim Y. J., Lee H. J., Lee C. Y. 2003. J. Agric. Food Chem. 51 :7292-7295. [9]Zrira, S.B. Benjillali. 1991. J. Ess. Oil.Res. 3(2) 117-118.). [10]Kechaou.N.,Maalej. M. A Drying Technology, Vol. 18, N°4-5, pp. 1109 – 1125. 2000. [11]ARHAB R., 2007. Etude de la fermentescibilitéin vitro et de la digestibilité in vivo de végétaux des zones arides et de sous produits de l’agronomie saharienne par l’estimation de l’activité métabolique du microbioberuminal d’ovins. Thèse de Doctorat. Université Mentouri Constantine. Algérie. 204 p.

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