Nature of the Camel Milk - Research Paper

Introduction

Camel's milk has been found to be highly nutritious. The milk has a white-opaque colour, sweet and sharp taste, but have sometimes been reported to be salty. The salty taste of camel's milk, which is not its natural taste, has been linked to the availability of water and to the type of fodder the animal has fed on. The milk is acidic, with its pH ranging from 6.5 to 6. On the other hand, its density varies from 1.025 to 1.032. This is the same as the pH of sheep's milk. When left to stand, there is increased acidity. Specifically, the concentration of lactic acid rapidly increases from 0.03% to 0.14% when the milk is left to stand for 2 hours and 6 hours respectively (Sisay and Awoke K. 2015, 2). Overall, its pH and density are lower than those of cow's milk.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

The composition of camel's milk has also been found to significantly differ from both the cow's and goat's milk. For instance, when compared to the colostrum of milk, camel's colostrum is whiter and more diluted. Colostrum obtained 3 hours after calving has been reported to have about 3.8% minerals, 7.2% lactose, 19.4% protein, 30.4% total solids, and 0.2% fat. However, the percentage of solids have been found to decline over time due to the decrease in the protein content. Similarly, mineral content decreases to 0.1% following calving.

On average, the protein composition of a camel's milk is 4.26 g/100 g product (Urbisinov et al. 1981, 1). Also, a look at the fraction composition of its proteins has shown that the milk is mostly comprised of casein (74.1%) and has little serum proteins (25.9%) of the total protein content. Urbisinov et al. (1981) have further revealed that the serum proteins in camel's milk are comprised of 17.8% proteoso-peptones, 13% globulins, and 18.8%, albumins. Additionally, camel's milk contains 36.1% of all essential amino acids. However, tryptophan not present in milk (Urbisinov et al. 1981, 1). Camel's milk has also been found to have high vitamin C content. Its vitamin C content has been found to range from 5.7 and 9.8 mg per cent. However, the vitamin C concentration rises as the lactation proceeds. Its vitamin C levels have been reported to be three-fold that of cow milk and one-and-one-half-fold that of human milk (Sisay and Awoke K. 2015, 2).

Camel milk has a high concentration of ash. The percentage of ash in camel milk ranges from 0.8 to 1.0 per cent, with the lowest ash content being found in milk produced by a dehydrated camel (Konuspayeva et al. 2009, 98). It has also been noted that the percentage of ash present in camel milk is affected by water consumed by the camel, analytical procedures, feeding, and differences in the breed (Mehaia et al. 1995, 115). The mean values for zinc (Zn), Manganese (Mn), iron (Fe), sodium (Na), potassium (K), and calcium (Ca) in camel milk is 0.53, 0.05, 10.5, 0.29, 59, 156, and 114 mg 100 g_1 respectively. Moreover, the level of mineral ions in camel milk is higher than those of bovine milk, especially the Mn, copper (Cu), Fe, K, and Na levels. On the other hand, the amount of Mg, phosphorous, and Ca content in camel milk has been found to be similar to that of bovine milk.

Camel milk has also been reported to have different fat content and type when compared to that of other animals. When the milk is left to stand, fat is dispersed as small globules throughout the milk. The diameter of these globules ranges from 1.2 to 4.2 microns; tiny in size. Unlike milk from other mammals, camel milk also has lower fat to total solids ratio of approximately 31.6 per cent. Specifically, its fat to total solids has been found to be lower than buffalo's 40.9 per cent. Unlike other animals, camel milk fats are protein bound. Consequently, it has been found that there is difficulty extracting fat from the milk through the standard technique of churning sour milk. Also, unlike in other animals, the extraction of vitamin A and carotene requires done through saponification due to their higher milk fat content. Consequently, the conventional method of extraction of vitamin A and carotene, petroleum ether method, is not applicable in camel milk. Moreover, even though camel milk has similar long-chained fatty acids present in the milk fat of other mammals such as ewe, buffalo, and cow, camel milk short-chained fatty acids are less than those found in the milk of the other mammals. Lastly, it has been reported that camel milk has higher polyunsaturated acids and polyunsaturated acids (volatile acids) contents than other mammals.

History of Development of Camel Milk as an Industrial Product

Like in bovine animals, many products can be obtained from camel milk. Some of these products include butter, cheese, butter, and yoghurt. It is, however, important to note that the production of these products from camel milk is highly difficult and near-impossible compared to producing the same from bovine milk. However, pasteurization of camel milk has been conducted successfully. Pasteurization is done using the same methods which are used to pasteurize cow or goat milk. Some of these methods include high-temperature short time pasteurization and batch pasteurization.

The Protein of Camel Milk Compared with Cows And Sheep

Casein protein of cow milk has been reported to be significantly higher than that of camel milk. More specifically, cow milk casein has a higher content of non-essential proteins as well as essential proteins (phenylalanine, lysine, and histidine) than casein of camel milk. With the exception of arginine, all other non-essential amino acids are higher in cow milk compared to camel milk. Other essential amino acids that have been found to be higher in cow milk a-casein than in camel milk a-casein include methionine, isoleucine, leucine, and phenylalanine. Moreover, in cow milk v-casein, essential amino acids (valine, phenylalanine, and histidine) have been found to be higher than in camel milk v-casein. However, lysine, threonine, and methionine essential amino acids are higher in camel milk v-casein than in cow milk v-casein (Salmen et al. 2012, 177). Overall, camel milk contains 3.27 (g/100 g) protein while cow milk contains 3.48 (g/100 g) protein (Soliman 2005, 118).

The total amount of protein in sheep milk has also been found to be higher than that found in camel milk. Specifically, sheep milk contains 5.5 (g/100 g) protein (Balthazar et al., 2017, 248) compared to camel's 3.48 (g/100 g) protein.

Ingredients

According to Vital Camel Milk Limited (2006) whole Pasteurized camel milk have no preservatives or other ingredients. The proximate minimum per 100 nutritional value of camel milk include 2.5g of milk fat, 3.0g of protein, 4.8g of carbohydrate, and 0.132g of calcium per 100g of milk.

Processing and Technology

Like milk from cows, camel milk is processed into final products by pasteurization. Pasteurization is a highly established technology of processing milk first developed by Louis Pasteur in 1864. Louis discovered that wine and beer could be prevented from abnormally fermenting by heating them to temperatures of about 57 oC for some few minutes. Pasteurization refers to a heat treatment procedure which involves heating a specific food for a certain period of time with the aim of killing particular microorganisms found in the food, and that may cause food spoilage and related diseases in human beings. Apart from beer and wine, the use of pasteurization to enhance the shelf life of foods has been extended to other foods such as milk, liquid egg, and juices.

Pasteurization is aimed at improving the shelf life of camel milk. There are many types of pasteurization techniques used in milk preservation. However, all of these approaches are based on the same principles of heating the milk to a particular temperature, heating milk for a specific duration, and packaging. It is worth noting that when the milk to be processed is on a small scale; holder pasteurizers are used. On the other hand, for large-scale processing of milk, pasteurization is conducted using High Temperature For Short Time (HTST) pasteurizers such as an external tubular heater, internal tubular heater, drum heater, and Danish heater.

The first step of milk processing is referred to as filtration. Filtration of milk for pasteurization is the first vital step for the removing M. tuberculosis (International Dairy Federation 1994, p. 133). After the milk has been filtered, it is rapidly heated to the recommended temperature and rapidly cooled down. The temperatures recommended for pasteurization and the corresponding time are as shown in the figure below:

Figure 1: Pasteurization Temperature and Time

Batch Pasteurization

Batch pasteurization, also referred to as Low-Temperature Long Time (LTST), involves heating up milk to a temperature of 63 oC in a large tank and ensuring that the temperature is maintained at 63 oC for at least half an hour. To ensure that each particle of the milk is heated to the required temperature, it is advisable to continuously stir the milk while heating. This is a simple process which can be carried out at home without the need for any high-end machines.

High-Temperature Short Time Pasteurization

High-Temperature Short Time Pasteurization (HTST), also called flash pasteurization, is the most preferred way of pasteurizing milk in the industry. The HTST process has been found to lead to killing 99.999% or a higher percentage of harmful bacteria. Based on the Standard US protocol, introduced in 1933, pasteurization of milk using HTST requires heating of milk to a temperature of 71.7 oC for 15 seconds. HTST is the preferred method of pasteurization of large volume of milk in industries because it is a continuous process and faster than other pasteurization techniques. It has also been found to be more energy efficient because it is more energy efficient in that energy from pasteurized milk can be used to preheat incoming raw milk before channelling the milk to a heat exchanger. However, because the temperature used to pasteurize the milk is higher than the one used in batch pasteurization, the flavour of the milk is slightly altered and tastes cooked.

The primary components of a pasteurization plant include "a raw milk tank, a boiler, a heat exchanger, a thermally insulated holding tube, a set of diverter valves, raw milk pump, hot water pump, a variable frequency, drive, three J-type thermocouples, and a control box to control the entire pasteurization process." All these parts are fixed on a trolley with wheels for easier movement.

An overview of the HTST process is shown in diagram 2 below. In the first step of the pasteurization process, cold raw milk at a temperature of 4 C is sucked into the regenerator component of the pasteurizer. In the regenerator, the cold raw milk is heated to a temperature of between 57 C - 68 C using heat released by hot pasteurized milk which flows counter-currently on the opposite side of thin, stainless steel plates. From here, the raw milk at 57 C - 68 C is passed via a timing pump which is meant to deliver the milk throughout the HTST system under positive pressure. The pressure in the timing pump forces the warmed raw milk via the heater section. In the heater section, hot water flowing on opposite sides of the plates are used for heating milk to a temperature of not less than 72 C.

After that, the milk, still at a temperature of 72 C and under pressure is passed via the holding tube where it is held for a minimum of 16 seconds. The maximum speed at which the milk flows is regulated by the timing pump's speed, the holding tube's length and diameter, and surface friction. The milk then flows over indicating thermometer, regarded as the most precise temperature measurement, then through a recorder controller which is used to...