Chemical composition of Infraspinatus , Triceps brachii , Longissimus thoraces , Biceps femoris , Semitendinosus , and Semimembranosus of Bactrian ( Camelus bactrianus ) camel muscles

The objective of this study was to determine chemical composition of Infraspinatus, Triceps brachii, Longissimus thoraces, Biceps femoris, Semitendinosus, and Semimembranosus muscles from nine Bactrian carcasses (2-3 years of age). The left side muscles were collected and kept in a chiller (3-4oC) for 48 hrs then stored at –20oC. Chemical analyses were carried out to determine moisture, crude protein, fat (ether extract), ash, essential and non-essential element contents. The Infraspinatus, Triceps brachii, Biceps femoris, Semitendinosus and Semimembranosus muscles had significantly higher moisture content than Longissimus thoraces muscle. The range of variation in protein content among the muscles was from 17% (Longissimus thoraces) to 18.8% (Semitendinosus). The Longissimus thoraces muscle had significantly higher fat content than other muscles. The Longissimus thoraces muscle had significantly lower phosphorus, magnesium, sodium and potassium contents than Infraspinatus, Triceps brachii, Biceps femoris, Semitendinosus and Semimembranosus muscles. Small variation in iron, zinc, lead, cadmium, copper, cobalt and magnesium contents were found among selected muscles. This study indicated that muscle location of the Bactrian camel may have an effect on its chemical composition.


Introduction
Camel has been well recognized as an important meat animal in less developed parts of the world but its meat is gaining importance due to its low fat content and it is relatively rich in polyunsaturated fatty acids (Kadim et al., 2008).Meat is an essential source of protein, energy, vitamins and minerals for human nutrition.However, recently there has been a concern about the health hazards of diets containing high levels of animal fat and cholesterol.These have been identified as a cause of a wide range of health problems including obesity, cardiovascular diseases, cancer, etc.Consequently, low fat diets have been attaining more acceptability.Camel meat is considered leaner as they produce less proportions of carcass fat than other meat animals.Camel meat has a good market potential, as it could become an ideal choice for health conscious consumers (Kadim et al., 2008).The chemical composition of camel meat is similar to meats from other species where an inverse relationship existed between the moisture and protein contents and the fat content.The chemical composition of camel meat is an important indicator of meat functionality.Moisture content of camel meat plays an important role in the keeping and eating qualities of meat (Kadim et al., 2006) whereas protein and fat contents dictate the manufacturing quality of meat.
In Kazakhstan, camel meat is consumed and preferred by the local population and camels are slaughtered regularly for social, special occasions and certain time of the year.Kazakhstan has 168,000 heads with 80% Bactrian camels (Camelus bactrianus).Although, the nutritive value of camel meat has recently become a growing aspect in the marketing of meat products in Kazakhstan, there is no information on its meat composition.Therefore, it is time to establish better criteria of Bactrian camel meat composition.This will be practically applicable for every region raising Bactrian camels for meat production.An efficient marketing system for the Kazakhstan Meat Industry needs more information on meat composition in relation to consumers.The aim of this study was to investigate the chemical composition of Infraspinatus, Triceps brachii, Longissimus thoraces, Biceps femoris, Semitendinosus, and Semimembranosus of Bactrian camel muscles in Kazakhstan.

Animals and meat samples
Nine Bactrian camels (2 to 3 years of age) were slaughtered at Zhengis Sharua Kozhalygy camel farm, Kyzylorda, Kazakhstan.The Infraspinatus, Triceps brachii, Longissimus thoraces, Biceps femoris, Semitendinosus, and Semimembranosus muscle samples were dissected within 20 min postmortem.Each muscle was trimmed off external fat and transported in an insulated cool box and kept in a chiller (3-4 o C) for 48 hrs for proximate analysis.

Proximate composition
All visible fat was removed from each muscle before they were cut into small pieces.Twohundred grams of meat sample were placed in plastic containers and then dried in a thermo freeze dryer (Modulyol-230, Milford-UK) for five days under 100-mbar pressure at -50ºC.The frozen dry samples were ground using Pansonic-Mixgrinder, Model MX119N-Japan grinder in order to obtain a homogenous mass for chemical analyses.The proximate chemical composition of the muscle tissue was determined as described by Kadim et al. (2009).In brief, protein was determined using a Foss Kjeltec 2300 Nitrogen/Protein Analyzer.Fat (ether extract) was determined by Soxhlet extraction method, using petroleum ether.Ash content was determined by ashing samples in a muffle furnace at 500ºC for overnight.

Mineral composition
Evaluation of mineral levels in camel meat was carried out in two phases, digestion of samples and analyses.Stock of Co, Zn, Cu, Mn, Pb, Mg, Ca, Cd, and P standard (1000mg/L) solution were purchased from Sigma-Aldrich (Chemie GmbH.Riedstrasse 2. D-89555.Steinheim Germany), while K and Na standards (1000mg/L) solutions were obtained from Sherwood (The Paddocks, Cherry Hinton Road, Cambridge, UK).Working standard was prepared by suitable serial dilutions of stock (1000mg/L) of all standard in deionized water and in house standard reference materials used for validation of the method.Complete digestion was achieved using a CEM microwave system Model MARS 907511(CEM Cooperation, Mathews, North Carolina, USA) with a maximum temperature of 200°C in closed polytetrafluoroethylene (PTFE) vessels.Concentrated HNO 3 was used for the digestion of samples.In brief 10 ml of conc.HNO 3 were added to each digestion vessels.They were then heated to 200°C over a 15 minutes period, and then held at 200°C for another 15 minutes.The digest obtained was collected in 100-ml volumetric flasks and made up to volume.Measurements of Co, Zn, Cu, Mn, Pb, Mg, Cd and Ca were carried out on Atomic Absorption Spectrophotometer (AAS) system type Shimadzu Model AA-6800, equipped with GFA-EX7 240V CE Graphite Furnace, HVG-1 Hydride Vapor Generator, MVU-1A Mercury Vaporizer and ASC-6100 Auto Sampler (Japan).Whereas K and Na were analysis by Sherwood Flame photometer, model 420 equipped with Auto sampler model 860 (The Paddocks, Cherry Hinton Road, Cambridge, UK) and P were analysis by Helios UV Visible Spectrophotometer, model Helios Beta (Thermo Electron Corporation, UK).

Statistical analysis
The data were analyzed using General Linear Model's procedure (SAS, 1993) to compare the effect of muscle type (Infraspinatus, Triceps brachii, Longissimus thoraces, Biceps femoris, Semitendinosus, and Semimembranosus muscles) on proximate composition essential and noessential elements of Bactrian camel.Significant differences between means were assessed using the least-significant-difference procedure.

Results and Discussion
The Infraspinatus, Triceps brachii, Biceps femoris, Semitendinosus, and Semimembranosus muscles had significantly ((P < 0.05) higher moisture content than Longissimus thoraces muscle (Table 1).With the exception of Longissimus thoraces muscle, no differences in moisture content between muscles in the present study is agreement with findings of Babiker and Yousif (1990), El-Faer et al. (1991), Al-Shabib and Abu-Tarboush (2004) and Alfawaz (2004).They reported that different muscles from the same animal appear to have similar moisture contents.In the present study, the difference between Longissimus thoraces and other muscles might be due to higher fat content of the Longissimus thoraces muscle.Similarly, Shehata (2005) reported that Biceps femoris muscle had higher moisture content (74.2%) compared with Longissimus thoraces muscle (69.2%) due to the higher fat content in the Longissimus thoraces muscle.However, the average value for moisture of Longissimus thoraces muscle was within the range reported for moisture (70-77%) for Longissimus thoraces muscle of dromedary camel (Kilgour, 1986;Babiker and Yousif, 1990;El-Faer et al., 1991;Elgasim and Alkanhal, 1992;Al-Ani, 2004;Cristofaneli et al., 2004;Kadim et al., 2009).The moisture contents of Triceps brachii, Semitendinosus and Biceps femoris muscles were higher than reported by Bebiker et al. (1990) and Gheisari et al. (2009).Moisture is important as far as its pronounced effects on meat shelf life, processing potential and sensory characteristics (Kadim et al., 2009).The current study showed that moisture content of Bactrian camel meat was higher than dromedary camel meat.
The protein content of Bactrian camel muscles was in the range 17.0 to 18.8% (Table 1).No significant differences in protein content between the Infraspinatus, Triceps brachii, Longissimus thoracis, Semitendinosus, Semimembranosus, and Biceps femoris muscles in the present study is on line with the conclusions of others (El-Faer et al., 1991;Dawood and Alkanhal, 1995;Kadim et al., 2006).Protein contents of Bactrian camel muscles were slightly lower than those reported by Bebiker and Yousif (1990) and Gheisari et al. (2009) and Kadim et al. (2006) for dromedary camel's muscles.Breed may cause slight differences in camel meat composition.Studies from Saudi Arabia (El-Faer et al., 1991;Elgasim and Alkanhal, 1992; Al-Shabib and Abu-Tarboush, 2004) reported lower protein content than those from United Arab Emirates, Iran, Sudan and Syria (Babiker and Yousif, 1990;Kadim et al., 2006Kadim et al., , 2009;;Gheisari et al., 2009;Al-Bachir and Zeinou, 2009).However, content of Longissimus thoracis muscle in Bactrian camel is similar to those of dromedary Longissimus thoracis (16.8%) muscle (Abdelhadi et al., 2012).The difference of protein content between this study and other studies may be due to breed and age differences.
The ash content in the Bactrian camel muscles was reported in the range 0.90 to 1.10% (Table 1).Many studies found that the ash content vary with muscles and meat cuts (Babiker and Yousif, 1990;Dawood and Alkanhal, 1995;Gheisari et al., 2009.Ash contents for Longissimus thoracis, Triceps brachii, Semitendinosus, and Biceps femoris Bactrian muscles were slightly lower than dromedary camel meat (Bebiker et al., 1990;Kadim et al., 2006Kadim et al., , 2009;;Abdelhadi et al., 2012).Camel meat has relatively lower ash content than beef, lamb and goat meat (Elgasim and Alkanhal, 1992;Gheisari et al., 2009).The present study indicated that no significant differences among the six muscles on essential or non-essential element contents (Table 2).Minerals are generally classified as either that are required for growth and optimal health or toxic elements, which poses health risk to organism.Both the deficiency and excess intake of essential elements as well as exceeding the safe limits of toxic elements can be detrimental to human health.
Muscles contained high levels of potassium, followed by sodium, phosphorus, magnesium and calcium.Comparison of phosphorus, magnesium, sodium and potassium contents of Bactrian camel muscle samples showed significant differences between selected muscles (Table 2).Phosphorus is the third most abundant element in Bactrian camel meat (2.29-3.97mg/100g).The Longissimus thoracis muscle had significantly (P<0.05)lower phosphorus content than other muscles, which it may be due to biological role of each element in muscle physiology.Calcium content (mg/100g) for dromedary camel meat cuts were reported to be in the range of 1. 33-11.48 (Faer et al., 1991;Elgasim and Alkanhal, 1992;Dawood and Alkanhal, 1995;Rashed, 2002;Badiei et al., 2006;El-Kadim et al., 2009).However, the level of variation between the current study and the previous studies may be due to physiological factors, which play a major role in determining the calcium contents in camel meat.Small variation in calcium content was reported among different meat cuts.The variation between four to six different meat cuts in dromedary camel were 19-27% (El-Faer et al., 1991;Dawood and Alkanhal, 1995;Rashed, 2002) whereas up to 144% variation in calcium content can be observed among different meat cuts from different studies (Kadim et al., 2008).Magnesium is another essential mineral for the normal contractions of muscles.The present study showed that Infraspinatus (2.48 g/100g) and Longissimus thoracis (2.51 g/100g) muscles contained significantly lower magnesium than Triceps brachii (3.03 g/100g), Semitendinosus (3.5 g/1oog), Semimembranosus (3.27 g/100g) and Biceps femoris (3.45 g/100g) muscles.Meat from dromedary camels appears to have lower magnesium content (0.01 mg/100g) across four different meat cuts (El-Faer et al., 1991;Elgasim and Alkanhal, 1992).However, meat from camels in dromedary camel appears to have higher magnesium content and the concentration varied among different meat cuts (Rashed, 2002).Sodium content in camel meat was in the range of 3.59 -5.78 mg/100g (Table 2).The Longissimus thoracis (3.59 g/100g) muscle had significantly lowest sodium content while the Semitendinosus (5.78 g/100g) muscle had the highest content comparing to other muscles.Similar conclusion was reported by Elgasim and Alkanhal (1992); Rashed (2002) and Kadim et al. (2006).They found that loins region had the lowest sodium content among the different camel meat cuts tested.Potassium has a bioactive role in muscle function, particularly energy metabolism and neuromuscular excitability (Allen, 1989).The Longissimus thoracis muscle had significantly (P<0.05)lower potassium content than other five muscles tested.Although, no significant difference for micro elements among the selected muscles in the present study, zinc, lead cadmium, copper, cobalt and magnesium levels were within the range of dromedary camels (El-Faer et al., 1991;Dawood and Alkanhal, 1995;Rashed, 2002;Kadim et al., 2006).Iron content in camel meat (1.16-3.39mg/100g) varied among different meat cuts (El-Faer et al., 1991;Dawood and Alkanhal, 1995;Rashed, 2002) which is expected due to the different physiological requirements of myoglobin of different muscles.As with other red meat species, meat cut containing oxidative muscles (Semitendinosus, semimembranosus and biceps femoris) has higher iron content than glycolytic muscles (Longissimus thoracis).However, the range of iron content in the present study was low compare to other camel study, which may be due to different methods of determination, age and location of meat samples.

Conclusion
The composition of Bactrian camel meat is similar to other red meats, but it can be considered as a healthy option due to the low fat content of the meat.A better understanding of chemical composition of individual camel muscles may benefit the meat industry to maximize potential marketable by improving nutritive value of camel meat.
1SEM: standard error for the mean.
1SEM: standard error for the mean.