Chemical composition and quality of camel meat

Chemical composition and quality of camel meat

Meat Science 27 (1990) 283-287 Chemical Composition and Quality of Camel Meat S. A. Babiker & O. Kh. Yousif Institute of Animal Production, Universi...

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Meat Science 27 (1990) 283-287

Chemical Composition and Quality of Camel Meat

S. A. Babiker & O. Kh. Yousif Institute of Animal Production, University of Khartoum, PO Box 32, Khartoum, North Sudan (Received 25 May 1989; revised version received 14 August 1989; accepted 18 August 1989)

A BS TRA C T

L. dorsi, Semitendinosus and Triceps brachii muscles from the camel had similar moisture, protein and fat content, but significantly ( P < O'05) different ash content. These muscles had also similar sarcoplasmic and myofibrillar protein concentrations. L. dorsi muscle had the highest content of collagen but a higher solubility of hydroxyproline than Semitendinosus and Triceps brachii muscles. It also had a brighter red colour. Water-holding capacity was not significantly different between the three muscles studied. Shear force and connective tissue strength were lowest in L. dorsi, intermediate in Semitendinosus and highest in Triceps brachii.

INTRODUCTION The desert camel, being adapted to harsh arid and semi-arid zones, is capable of converting the cover of these regions into animal products suitable for h u m a n consumption. At an age of 7 years a fattened camel can produce a carcase of 259 kg with a meat:bone ratio of 3"0 (Yousif, 1989). This offers considerable scope for utilization of camel meat to alleviate animal protein shortage, particularly in semi-arid zones. The quality of camel meat has received little attention. Earlier Leupold (1968) described the meat of the camel as palatable, but coarser than beef, varying in colour from raspberry red to brown red and having white fat. Knoess (1977) and Mukasa (1981) reported that camel compared favourably 283 Meat Science 0309-1740/90/$03-50© 1990ElsevierSciencePublishersLtd, England. Printed in Great Britain

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with other livestock in carcase yield and quality. The quality of meat produced by younger animals (5 years or less) was comparable to beef in taste and texture. However, since animals are usually slaughtered at the end of their productive life camel meat is usually tough. Mukassa (1981) in Kenya, reported the mean age for animals slaughtered at one market as 14-5 years. Chemically, camel meat contains more moisture than beef. The protein content of the camel meat is significantly greater and intramuscular fat is significantly lower than beef. The camel meat is also found to have significantly lower sarcoplasmic proteins than beef (Babiker & Tibin, 1986). In this study the chemical composition and the eating quality attributes of three major camel muscles are evaluated.

MATERIAL AND METHODS

Longissmus dorsi (lumbar part), Semitendinosus and Triceps brachii muscles were obtained from mature, well finished desert camels of 456 kg average liveweight. Slaughter method, dressing and carcase preparation have already been described (Yousif & Babiker, 1989). Muscles were dissected from the left sides after 24 h chilling at 4°C. Each muscle was divided into two portions, one for chemical analysis and the other for objective determination.

Chemical analysis Muscle samples were trimmed of visible connective tissue and fat and minced for chemical analysis. Protein, moisture, fat and ash were determined according to AOAC (1975). Protein fractionation was performed as described in Babiker and Lawrie (1983). Total collagen was determined by the method of Stegeman and Stadler (1967) while hydroxyproline solubility measurement was according to Hill (1966).

Objective measurements Muscle protein for objective determinations were used for colour measurements before they were frozen stored for subsequent shear force and connective tissue strength determinations. Colour measurements were performed using Hunterlab Tristimulus colorimeter model D25 M-2. Hunter lightness (L), redness (a) and yellowness (b) were recorded on muscle potions oxygenated for 2h at 4°C. Water-holding capacity was done according to Grau and Hamm (1953). An Instron Model I000 was used for

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shear force and connective tissue strength determinations. Muscle samples were thawed at 4°C for 24 h, trimmed o f external fat, cut to 5 x 5 x 7 cm and cooked for 1 h in a water bath at 80°C. Rectangular samples (cross section, 1 x 1 cm), 7 cm long with fibres parallel to the long axis and 10 m m cubes, were cut from the c o o k e d meat. The rectangular samples were used for shear force and the cubes for connective tissue strength determinations. Data were statistically analysed as in Snedecor and Cochran (1980).

RESULTS AND DISCUSSION

Meat chemical composition As seen in Table 1, camel L. dorsi, Semitendinosus and Triceps brachii muscles had similar moisture, protein and fat content, but the ash content differed significantly (P < 0-05) between the three muscles. These findings generally agreed with those o f Nasr et al. (1965). Abdel Baki (1957) and H a m m a n et al. (1962): who found that the L. dorsi muscles obtained from 5year-old camels had an average 19.4% protein, 76.2% moisture, 2.6% fat and 1.1% ash, the round muscles had 19.8% protein, 78"3% moisture and 3.8% fat while shoulder muscles had 22.3% protein, 76.1% moisture, 0.95% fat and 0.79% ash. The concentrations o f sarcoplasmic and myofibrillar proteins were not significantly different among the three muscles studied

TABLE 1 Chemical Composition of the Desert Camel Meat

Moisture (%) Protein (%) (N x 6.25) Fat (%) Ash (%) Sarcoplasmic proteins* Myofibrillar protein* Non-protein-nitrogen* Total collagen* Hydroxyproline solubility (%) Muscle pH

L. dorsi muscles

Semitendinosus muscle

Triceps brachii muscle

SE

75.89 21'63 1.43 1-05° 6.45 11.93 0"56' 9.22e 2"37gh 5-80

75.81 21.41 1.40 1.38b 6"51 11.48 0"52d 4-92 f 1"72hi 5.72

75.23 22"13 1.42 1.22" 6"76 11-81 0-53d 6.43 r 0-66i 5-69

0.45 0-35 0.11 0"35 0-24 0"35 0.01 0-69 0-79 0-03

* Percentage of fresh muscle weight. Means on the same line with different superscripts differ significantly: (P < 0-05 for a, b, and P< 0.01 for c, d, e,f, g, h and i).

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(Table 1). These values were in line with corresponding values reported by Babiker and Tibin (1986) for camel L. dorsi muscle. Non-protein nitrogen was significantly (P < 0.01) higher in L. dorsi than in the other two muscles, a finding which might be attributed to intramuscular difference in chemical composition reported by Lawrie (1979). Total collagen content was significantly (P < 0-01) greater in L. dorsi muscle than in Semitendinosus or Triceps brachii muscles. Unlike cattle, camel L. dorsi muscle was observed to be flat and traversed by strands of connective tissue; possibly to attach it in position and stabilize the h u m p over it. This might explain the increased collagen content of this muscle.

Eating quality attributes of camel meat Camel L. dorsi muscle had more lightness (L) and significantly (P < 0.01) more redness (a) and yellowness (b) values than Semitendinosus and Triceps brachff muscles (Table 2) indicating that this muscle appeared brighter red than the other two muscles. These colour differences might be due to differences in muscle myoglobin concentration and its chemical state. Semitendinosus muscle had significantly (P < 0-01) lower cooking loss than L. dorsi and Triceps brachii muscles which coincided with its superior waterholding capacity (Table 2). Muscle fibre strength, as measured by shear force, was lower in L. dorsi than in the other two muscles studied. Intermuscular differences and the possibility of early tenderization of this muscle induced by its relatively high pH might be implicated. Connective tissue strength of

TABLE 2 Quality Attributes of the Desert Camel Meat

Colour Degree of lightness (L) Degree of redness (a) Degree of yellowness(b) Water-holding capacity Cooking loss (%) Shear force (kg/cm2) Connective tissue strength (kg/cmz)

L. dorsi muscles

Semitendinosus muscle

Triceps brachii muscle

SE

32-23° 17.13" 9-01 2-8 37"95e 4.84 2-91g

30.67 13.77b 7-11 2.1 33.23f 5.67 3.45h

26-69 15"89°b 7.79 2-32 37.07e 5-76 4-13h

0-96 0"6 ff36 0.23 1-06 0.29 0-19

Means on the same line with differentsuperscripts differsignificantly:(P < 0.01 for a, b, c, d, e, f) (P< 0-001 for g,h).

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the L. dorsi muscle was also significantly (P < 0-01) lower than values for Semitendinosus and Triceps brachiimuscles. The former muscle was found to have more soluble collagen than the latter two muscles, possibly indicating less thermal stable bonds between collagen molecules and weaker connective tissue structure of this muscle. Triceps brachii had the highest shear force values, maximum connective tissue strength and least collagen solubility indicating that it was the toughest muscle in this group.

ACKNOWLEDGEMENT The authors would like to thank Mr Osman Ali A d a m and Mr Nesor Oquis for the computer typing of this manuscript.

REFERENCES Abdel Baki, M. M. (1957). Studies on Camel Meat. Bull. No. 110, Faculty of Agric., Cairo University, p. 13. AOAC (1975). Official Methods of Analysis. Association of Analytical Chemists, Washington, DC. Babiker, S. A. & Lawrie, R. A. (1983). Meat Sci., 8, 1. Babiker, S. A. & Tibin, I. M. (1986). Camel research papers from Sudan. ILCA, Addis Ababa, Ethiopia, p. 37. Grau, R. & Hamm, R. (1953). Naturwiss, 40, 39. Hamman, M. A., Hidik, M. E., Sherif, I. & Yousif, M. (1962). J. Arab. Vet. Med. Assoc., 22, 391. Hill, F. (1966). J. Food Sci., 31, 161. Knoess, K. H. (1977). Wld. Anita. Rev., 22, 139. Lawrie, R. A. (1979). Meat Science, 3rd edn, Pergamon Press, Oxford. Leupold, J. (1968). Les cahiers bleus Vet., 15, 1. Mukasa, M. E. (1981). The camel. A Bibliographical review. ILCA Monogr No. 5. Addis Ababa, Ethiopia. Nasr, S., El Bahay, G. & Mursy, A. W. (1965). J. Arab Vet. Med. Assoc., 25, 253. Snedecor, G. W. & Cochran, W. G. (1980). Statistical Methods, 7th edn, Iowa State University Press. Stegeman, H. & Stadler, K. (1967). Clin. Chem. Acta., 18, 267. Yousif, O. Kh. (1989). The desert camel as a meat producing animal. MSc thesis, University of Khartoum, Sudan. Yousif, O. Kh. & Babiker, S. A. (1989). Meat Sci., 26, 245.