Camel milk paper 2.pdf

WFL Publisher Science and Technology Meri-Rastilantie 3 B, FI-00980 Helsinki, Finland e-mail: [email protected]

Journal of Food, Agriculture & Environment Vol.8 (3&4): 16-20. 2010

www.world-food.net

Variations of physical and chemical properties and mineral and vitamin composition of camel milk from eight locations in Jordan Muhammad H. Aludatt 1*, Khalil Ereifej 1, Abdulaziz M. Alothman 2, Ali Almajwal 2, Hana Alkhalidy 1, Abdel Rahman Al-Tawaha 3 and Inteaz Alli 4 1

Department of Nutrition and Food Technology,Faculty of Agriculture, Jordan University of Science and Technology, P. O. Box 3030, Irbid, 22110, Jordan. 2 Department of Community Health Sciences, King Saud University, P.O.Box 10219, Riyadh 11433, Saudi Arabia. 3 Department of Biological Sciences, Al Hussein Bin Talal University, Maan, P.O. Box 20, Jordan. 4 Department of Food Science and Agricultural Chemistry, Macdonald Campus of McGill University, 21, 111 Lakeshore Road, Ste Anne de Bellevue, H9X 3V9, Canada. *e-mail: [email protected]

Received 10 August 2010, accepted 8 November 2010.

Abstract Camel milk was collected from eight locations in Jordan from north to south and was subjected to analysis of chemical and physical properties and vitamin and mineral contents. There was a wide variation in the chemical composition of camel milk collected from different locations with ranges of 21.0 (Al Jweideh) to 24.9% (Wadi Araba) for crude protein, 28.2 (Wadi Araba) to 45.8% (As Safawi) for fat, 6.1 (As Safawi) to 7.3% (Wadi Araba) for ash, 23.8 (As Safawi) to 41.0% (Al Jweideh) for lactose and 10.5 (Al Qatrana) to 17.2% (As Safawi) for dry matter. Camel milk acidity ranged from 0.12 to 0.15% and no significant differences were found in specific gravity values (1.01–1.03 g/ml) for milk collected from different locations. Refractive Index values varied significantly and ranged between 1.3470 (Al Qatrana) and 1.3524 (Al Khalidyah). Total soluble solids ranged between 9.5 (Al Jweideh) and 12.9% (Al Khalidyah). For mineral contents of camel milk collected from different locations, variations were significant for all analyzed minerals except for copper, iron and manganese. This study recommends using camel milk as a nutriceutical and functional food. The camel milk could be used as a new product in food technology. Key words: Camel, milk, Al Khalidyah, Al Hazeem, Al Umari, As Safawi, Al Hamra, Al Qatrana, Wadi Araba, Al Jweideh.

Introduction Certain characteristics of Arabian camels (Camelus dromedarius; one-humped camel) enable them to survive in arid regions 1-3. The dromedary camel is an important domestic animal in Jordan 4. The estimated number of camels in Jordan was 13,000 head in 2006 5. Beneficial health effects of camel milk components have been recognized as a component of interest due to their therapeutic properties such as anti-bacterial 6 , anti-viral 7 and anti-inflammatory 8 effects. Recently, the nutritional and preservation properties of protein subunits have been recognized9. Camel milk has a white opaque color, a faintly sweetish odor and a sweet but sharp taste 10 with pH range between 6.2 and 6.8 11, 12. Variations in the constituents of milk may be attributed to many factors such as breed, age, number of calvings, nutrition, management, stage of lactation and sampling technique 12-14. Chemical composition of camel milk varies in various parts of the world with a range of 3.5 to 4.5% protein, 3.4 to 5.6% lactose, 3.07 to 5.50% fat, 0.7 to 0.95% ash and 12.1 to 15% total solids 11. Little information has been reported about content of vitamins in camel milk. Camel milk contains less vitamin A, riboflavin 15, thiamin, folic acid and pantothenic acid than cow milk, while the contents of pyridoxine, vitamin B12 16 and vitamin E are about same 15. Vitamin C content is higher in camel milk when compared to cow milk 15. Studies that have been reported on mineral contents of camel milk are few. The major minerals of camel milk are chloride, phosphate and citrate of sodium, calcium and magnesium 16. Salts influence 16

the physical state and stability of milk protein 17. Mineral contents are affected by many factors such as health status of the udder and stage of lactation 17. However, little research and information are available on Jordanian camels and their milk 18, 19. Therefore, the present study was undertaken to study physical and chemical properties and mineral and vitamin composition of camel milk collected from different locations in Jordan. Materials and Methods Collection of milk: The study was conducted on camel herds in the Hashemite Kingdom of Jordan which has a land area of some 90,000 km2 from north to south. Eight samples of fresh dromedary camel milk (about 2 litres each) were collected from eight different locations in Jordan; Al Khalidyah, Al Hazeem, Al Umari, As Safawi, Al Hamra, Al Qatrana, Wadi Araba and Al Jweideh. Each sample was collected twice in a one month interval in the summer season (2006-2007). Samples were immediately cooled to 4°C, transported to the laboratory within 24 hours and kept frozen at -20°C until time of analysis. Gross chemical composition: Camel milk from eight different locations (Al Khalidyah, Al Hazeem, Al Umari, As Safawi, Al Hamra, Al Qatrana, Wadi Araba and Al Jweideh) were subjected to analysis of approximate chemical composition including moisture, protein (N X 6.38), fat and ash according to the procedure described

Journal of Food, Agriculture & Environment, Vol.8 (3&4), July-October 2010

by AOAC 20 and carbohydrate content was calculated by the difference. All measurements were carried out in 2 replicates.

Results and Discussion Chemical composition: Chemical composition of Jordanian camel milk expressed as g/100 g on dry weight basis collected from different locations is shown in Table 1. Crude protein content in milk varied between locations. Milk from Wadi Araba had the highest crude protein content of 24.9 % which differed significantly (P ≤ 0.05) from all locations except Al Umari (24.8%) and the lowest content was 21.0% in milk from Al Jweideh. These values were comparable to data reported by Haddadin et al. 19 and Mehaia 22 for the Jordanian camel milk but lower than values reported by Knoess 23, Mukasa-Mugerwa 24, Sawaya et al. 25, El Amin and Wilcox 26, Gorban and Izzeldin 27 and Isani and Baluch 28. The variation in protein contents may refer to the differences in breed 29, 30. For fat, the highest content was 45.8% in milk from As Safawi which differed significantly (P ≤ 0.05) from all locations, while the lowest value was 28.2% in milk collected from Wadi Araba which didn’t differ significantly as compared to Al Umari. These values were comparable to data reported by Knoess 23, Mukasa-Mugerwa 24, Sawaya et al. 25, El Amin and Wilcox 26, Mehaia 22, Gorban and Izzeldin 27 and Isani and Baluch 28, but higher than values reported by Haddadin et al. 19. This wide variation in fat content of camel milk may reflect differences in breed 29, 30 and diet 26. Gnan and Sheriha 11 found a negative correlation between fat contents and advanced lactation and parity. On the other hand, Gaili et al. 30 reported that the stage of lactation did not significantly affect the constituents of mature camel milk and El-Hag et al. 31 reported that parity was found to exert no influence on camel milk fat content. There were small differences between milk ash values from different locations; milk from Wadi Araba had the highest ash value (7.3%) which differed significantly (P ≤ 0.05) as compared to Al Khalidyah, Al Hazeem, As Safawi and Al Qatrana, and the lowest ash value was found in milk collected from As Safawi (6.1%). These values were comparable to data reported by Haddadin et al. 19, Knoess 23, Sawaya et al. 25, Mehaia 22 and Isani and Baluch 28 and lower than values reported by El Amin and Wilcox 26 and Gorban and Izzeldin27 while higher than values reported by Mukasa-Mugerwa 24. Variation in ash values may be due to differences in parity 31 and breed 29,30. Carbohydrate (lactose) varied between locations; milk collected from Al Jweideh had the highest lactose content (41.0%) which differed significantly (P ≤ 0.05) from all locations except Wadi Araba (39.8%), whereas milk collected from As Safawi had the lowest value (23.8%). These values were comparable to data reported by Haddadin et al. 19, Knoess 23, Mukasa-Mugerwa 24, Sawaya et al. 25, El Amin and Wilcox 26, Mehaia 22, Gorban and Izzeldin 27 and Isani and Baluch 28. Variation in lactose content

Physical properties: Acidity (expressed as lactic acid) and specific gravity were determined according to the procedure outlined in the AOAC 20. Refractive Index and total soluble solids were determined using Abbe Refractometer (VISTA C10) and pH value was determined using pH-meter (Cyberscan 500, Eutech Instruments, Singapore). Minerals determination: Calcium (Ca), sodium (Na), potassium (K), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn) and zinc (Zn) were measured using atomic absorption spectrophotometer according to the method outlined in the AOAC 20. Phosphorus (P) concentration was determined according to the method described by Fiske and Subbarow 21. Evaluation of vitamins Evaluation of fat-soluble vitamins (A and E) content: For each sample of camel milk, vitamin A and E were extracted from camel milk according to the method described by Farah et al. 15 with some modifications. One mL of milk was mixed with 1 mL of absolute ethanol and heated to 80°C in a water bath for 5 min under nitrogen and stirred using a magnetic stirrer. Then 1 mL of methanolic NaOH (12.5 M) was added and the mixture saponified for 20 min, cooled to room temperature. The saponification mixture was extracted with 1 mL hexane by shaking mechanically for 10 min. One mL of the internal standard (1 µg retinol in ethanol and 50 µg tochopherol in ethanol) was added and the solvent was evaporated by a stream of nitrogen and the mixture was reconstituted with 200 µL mobile phase (95% methanol, 5% water). A total of 100 µL of the clear organic phase was subjected to Reversed Phase-HPLC to separate and to identify the retinol and α-tocopherol content (Shimadzu, Jaban) equipped with a System Controller (SCL-10A vp) for high pressure solvent delivery, an autoinjector (SIL-AOAD vp), a programmable detector module (SPD-10A vp) and C18 reverse phase column; 250 x 4.6 mm column (M Bondapak, Waters, USA). Chromatographic data were analyzed by the CIASS-vp (version 6.1), translated into PRN format for Microsoft Excel manipulation. Isocratic elution was carried out with mobile phase (95% methanol, 5% water) with UV/Visible detector (287 nm). Elution was performed at a flow rate of 2.5 mL/min with a 50 min.

Evaluation of water-soluble vitamin (C) content: Determination of vitamin C (L-ascorbic acid) was conducted according to the method outlined by AOAC 20 using titrimetric method. This method is based on L-ascorbic acid oxidation by 2,6-pdichlorphenolindophenol into dehydroascorbic acid until color Table 1. Chemical composition of camel milk collected from different locations in Jordan 1. of reagent turned into colorless. Camel milk location Al Khalidyah Al Hazeem Al Umari As Safawi Al Hamra Al Qatrana Wadi Araba Al Jweideh LSD

Statistical analysis: The results reported in this work were the average of at least two measurements. Data were analyzed using the general linear model (GLM) procedure with SAS Version 8.2 software package (SAS 2002 Institute Inc., Cary, NC, USA). Means were separated by using the least significant difference (LSD) analysis at a P value of ≤ 0.05.

Protein (%) 21.5cd 21.3de 24.8ab 24.4b 21.9c 21.2de 24.9a 21.0e 0.454

Fat (%) 42.8b 40.0c 29.1f 45.8a 34.7d 39.4c 28.2f 31.2e 1.34

Ash (%) 6.5cdef 6.2ef 7.2ab 6.1f 6.8abcd 6.7bcde 7.3a 7.0abc 0.519

Carbohydrate (%) 29.3e 32.7d 39.0b 23.8f 36.7c 32.8d 39.8ab 41.0a 1.61

Dry matter (%) 16.5b 15.1c 10.7g 17.2a 12.9d 10.5h 12.5e 12.1f 0.163

Means within a column with different superscripts differ significantly (P ≤ 0.05). Means are average of two replicates and expressed in g/100 g (dry weight basis).

a-h 1


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may be due to differences in parity 31, breed 29, 30 and stage of lactation with the lowest percentage contents found with advancing lactation 11. Milk from the eight different locations differed significantly in the dry matter (P ≤ 0.05); the highest value was found in milk from As Safawi (17.2%) and the lowest one in milk from Al Qatrana (10.5%). These values were comparable to data reported by Haddadin et al. 19, Knoess 23, Mukasa-Mugerwa24, Sawaya et al. 25, El Amin and Wilcox 26, Mehaia 22 and Isani and Baluch 28, but higher than the values reported by Gorban and Izzeldin 27. Variation in dry matter might be due to breed, season, parity and feed that would affect water content and is inversely proportional to total solids 29-32. Several studies reported data on gross chemical composition of camel milk. Variations in breed, age, number of calving, nutrition, management, stage of lactation and sampling technique may be attributed to differences in chemical composition 13, 14.

Mineral composition: Mineral contents including Ca, Na, K, Cu, Fe, Mg, Mn, Zn and P of Jordanian camel milk collected from different locations in Jordanreported on dry weight basis (mg/100 g) are shown in Table 3. Calcium content varied between locations; the highest value was found in milk from Wadi Araba (1675.0 mg/ 100 g) which differed significantly (P ≤ 0.05) from all locations and the lowest value found in milk from Al Hazeem (516.5 mg/100 g). These values were comparable to those reported by Haddadin et al. 19, Sawaya et al. 25 and Gorban and Izzeldin 27 and remarkably higher than values reported by El Amin and Wilcox 26. Sodium content in camel milk ranged between 217.9 (Al Khalidyah) and 488.0 mg/100 g (Wadi Araba). The highest value of individual mineral content in camel milk was for K, values ranged between 1106.6 (Al Hamra) and 2466.2 mg/100 g (Al Umari). These values were comparable to those reported by Haddadin et al. 19 and El Amin and Wilcox 26 but lower than values reported by Sawaya et al. 25 and Gorban and Izzeldin 27. Variations in Na and K contents may be attributed to the effect of seasonal heat and water Physical properties: Some physical characteristics of Jordanian intake 34. Cu content in milk varied but not significantly between camel milk collected from different locations in Jordan are shown the eight locations. It ranged between 0.170 (Al Khalidyah) and in Table 2. Camel milk acidity (in terms of lactic acid content) 2.10 mg/100 g (Wadi Araba). Haddadin et al. 19 found trace amounts ranged between 0.12 and 0.15% and its specific gravity between 1.01 and 1.03 g/mL with no significant difference between locations. of copper in Jordanian camel milk. Camel milk iron from Al Hamra Acidity values were comparable to those reported by Sawaya et had the highest content of 3.54 mg/100 g and milk from Al Jweideh al. 25, Abu-Lehia 13, El Amin and Wilcox 26, Mehaia 22, Mehaia et the lowest one of 0.330 mg/100 g, with no significant differences al.29 and Khaskheli et al. 32. Specific gravity values were comparable between locations. Fe content in Jordanian camel milk is to values reported by Khaskheli et al. 32. comparable to data reported by Haddadin et al. 19, Sawaya et al.25, Highest refractive index was 1.3524 in milk from Al Khalidyah El Amin and Wilcox 26 and Gorban and Izzeldin 27. Variation in camel milk Fe content may possibly reflect breed rather than diet which differed significantly (P ≤ 0.05) from values in milk from Al differences 27. The high content of Fe in camel milk suggests that Umari, Al Hamra, Al Qatrana, Wadi Araba and Al Jweideh. The lowest value was 1.3470 in milk from Al Qatrana, which did not it might be a better alternative to human milk under circumstances differ significantly from milk from Al Jweideh. H ighest total soluble where iron supplementation is required for infants aged between solids content was also in milk from Al Khalidyah with a value of 6 and 12 months. This suggestion is supported by the fact that 12.9%, which also differed significantly (P ≤ 0.05) from Al Umari, the majority of Fe in camel milk is located in the low molecular Al Hamra, Al Qatrana, Wadi Araba and Al Jweideh. The lowest weight fraction that is easily accessible for intestinal absorption value was 9.5% in milk from Al Jweideh. Milk composition is and may facilitate the bioavailability of this element 35. It seems that camel milk could be considered as a good source of iron not responsible for variations in specific gravity and total soluble only for infants, but also for other groups whether healthy or with solids, while fat globule and casein micelles are the main health problems due to anemia or malnourishment. Mg content in contributors for the variation in refractive index. Moreover, camel milk ranged between 29.7 and 104.7 mg/100 g in milk from Al variation in acidity may refer to differences in stage of lactation 33. Camel milk pH ranged from 6.5 to 6.6 and resembled the values Khalidyah and Wadi Araba, respectively. These values were reported by Mehaia 22 and Khaskheli et al. 32, but was higher than comparable to values reported by Sawaya et al. 25, El Amin and values reported by Sawaya et al. 25 and Gorban and Izzeldin 27. pH Wilcox 26 and Gorban and Izzeldin 27, but much higher than values value can be affected by feed and availability of water 27. reported by Haddadin et al.19. Manganese highest value was 0.815 mg/100 g in milk from Al Hamra, while it was in non-detectable amount in milk collected from Al Khalidyah, Al Umari, Al Qatrana and Wadi Araba. Manganese content was lower than that reported by Sawaya et al. 25 and Gorban and Table 2. Some physical characteristics of camel milk collected from Izzeldin27. A value of 5.81 mg/100 g was found to be the different locations in Jordan 1. highest Zn content in camel milk obtained from Wadi Araba Specific Total Camel milk Acidity2 Refractive and 0.715 mg/100 g was the lowest value in milk from Al gravity soluble pH location (%) index (g/mL) solids (%) Umari. Zinc values in this investigation were comparable to Al Khalidyah 0.14ab* 1.03a 1.3524a 12.9a 6.5b those reported by Sawaya et al. 25 and Gorban and Izzeldin27. a a ab ab a Al Hazeem 0.15 1.02 1.3520 12.7 6.6 b a c c b Milk collected from Al Hamra had the highest content of P 1.02 1.3495 11.3 6.5 Al Umari 0.12 (771.6 mg/100 g) that differed significantly (P ≤ 0.05) from all As Safawi 0.15a 1.03a 1.3520ab 12.7ab 6.5b Al Hamra 0.15a 1.02a 1.3480d 10.1d 6.5b locations except Al Umari (745.4 mg/100 g). Milk collected 1.02a 1.3470e 9.6e 6.6a Al Qatrana 0.14ab from Wadi Araba had the lowest content of P (588.8 mg/100 a a c c b 1.02 1.3495 10.9 6.5 Wadi Araba 0.15 g). The content of P in this investigation was comparable to Al Jweideh 0.14ab 1.01a 1.3474de 9.5e 6.5b LSD 0.024 0.024 0.0009 0.416 0.058 that reported by Haddadin et al. 19, lower than that reported Means within a column with different superscripts differ significantly (P ≤ 0.05). by Gorban and Izzeldin 27 but higher than values reported by a-e 1

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Means are average of two replicates. 2 Acidity was computed as lactic acid.


Table 3. Mineral contents of camel milk collected from different locations in Jordan 1. Camel milk location Al Khalidyah Al Hazeem Al Umari As Safawi Al Hamra Al Qatrana Wadi Araba Al Jweideh LSD

Ca

Na e*

607.3 516.5e 958.2d 555.0e 1490.2b 1170.2c 1675.0a 1275.1c 167.6

K e

217.9 237.2e 389.1bc 250.8e 398.0b 366.9bcd 488.0a 382.5bcd 61.76

Cu cdef

1356.7 1467.4cd 2466.2a 1497.9c 1106.6f 1422.0cde 1895.9b 1150.0ef 284.5

Fe a

0.170 1.32 a 0.505 a 0.515 a 2.07 a 1.92 a 2.10 a 0.400 a 2.71

Mg a

1.43 3.25 a 0.420 a 2.78 a 3.54 a 1.00 a 3.46 a 0.330 a 5.03

Mn d

29.7 33.1d 38.2d 30.0d 69.8bc 68.0bc 104.7a 72.2b 10.85

ND 0.005 a ND 0.120 a 0.815 a ND ND 0.460 a 1.09

Zn

P bc

2.86 1.51bc 0.715c 2.69bc 3.94ab 3.11bc 5.81a 1.41c 2.48

697.6bcde 645.2efg 745.4ab 655.1bcdef 771.6a 706.7bcd 588.8g 707.9bc 57.97

a-g Means within a column with different superscripts differ significantly (P ≤ 0.05). 1 Means are average of two replicates and expressed in mg/100g in dry weight basis. ND = not detected.

Sawaya et al. 25 and El Amin and Wilcox 26. Variations in the major mineral contents (Ca, Na, K, and P) of camel milk could be due to breed, feeding, stage of lactation, drought conditions or use of different analytical procedures 17, 29. Variations in the levels of trace elements could be due to variations in the levels of these elements in the feed and water, breed differences and/or use of different analytical procedures 29. Vitamin A and E and ascorbic acid contents: Vitamin A, C (ascorbic acid) and E contents of Jordanian camel milk collected from different locations in Jordan reported on dry weight basis (mg/100 g) are shown in Table 4. Vitamin A content varied between locations and ranged from 0.02 to 0.09 mg/100 g in milk collected from Al Qatrana and Al Khalidyah, respectively. These values were lower than those reported by Haddadin et al. 19 and Sawaya et al. 25. Variation in vitamin A content could be related to differences in feed and breed 33. Vitamin C content in camel milk varied between locations and ranged from 15.7 to 44.7 mg/100 g from Al Hazeem and Al Jweideh, respectively. Vitamin C content was comparable to those reported by Haddadin et al. 19, Knoess23, Sawaya et al. 25 and Mehaia 22. Variation in vitamin C content may be due to differences in the stage of lactation and parity 36. Low pH of camel milk appears to be correlated with the high vitamin C content, giving the milk its sweet taste, which can be masked if the animal eats salty or bitter vegetation 37. The availability of a relatively fair amount of vitamin C in camel milk is of significant relevance from the nutritional standpoint in the arid areas where fruits and vegetables containing vitamin C are scarce 15. Vitamin E content in camel milk ranged between 0.32 and 0.85 mg/100 g in milk collected from Wadi Araba and As Safawi, respectively. These values were substantially higher than those reported by Haddadin et al. 19. Variation in vitamin E content depends to some extent on feed 33. Table 4. Vitamin A, C (ascorbic acid) and E contents of camel milk collected from different locations in Jordan 1. Camel milk location Al Khalidyah Al Hazeem Al Umari As Safawi Al Hamra Al Qatrana Wadi Araba Al Jweideh LSD

Vitamin C 16.1ef 15.7f 26.2c 18.7e 31.6b 27.4c 23.1d 44.7a 2.65

Vitamin E 0.49f 0.83ab 0.75abc 0.85a 0.62cdef 0.67bcde 0.32g 0.71abcd 0.16

Means within a column with different superscripts differ significantly (P ≤ 0.05). Means are average of two replicates and expressed in mg/100g (dry weight basis).

a-g 1

Vitamin A 0.09a 0.04bc 0.05b 0.03cd 0.04bc 0.02d 0.03cd 0.04bc 0.01

Conclusions From the foregoing results it can be concluded that there was a wide variation in the chemical composition of camel milk collected from different locations. Results indicated that milk from Wadi Araba had high protein, ash and carbohydrate contents, while fat content was low compared to milk collected from other locations. Generally, camel milk may provide a valuable amount of minerals. Also, milk collected from Wadi Araba was suggested to be a good source of minerals including Ca, Na, Cu, Fe, Mg and Zn. This study demonstrated that camel milk could be considered as a source of high antioxidant activity due to the high content of vitamin C and E. Milk collected from Al Jweideh had the highest amount of vitamin C. Availability of good amount of vitamin C in camel milk is of significant importance from the nutritional standpoint in arid areas where fruits and vegetables containing vitamin C are scarce due to its involvement in important functions in the human body. Camel milk should be more exploited as a new source of nutrients for varying the Jordanian diet and to benefit from its functional ingredients and natural components. Further studies are needed to investigate the influence of genetic and environmental factors on camel milk composition collected from different locations.

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