Changes in Chemical Composition of Alxa Bactrian Camel Milk During Lactation

Abstract

Changes in chemical composition of Alxa bactrian camels reared in Inner Mongolia (China) during lactation were investigated. Colostrum and milk samples from 10 nomadic female camels in their first season of lactation were collected periodically from parturition until 90 d postpartum (PP). The average contents of gross composition were 14.23% protein, 4.44% lactose, 0.27% fat, 0.77% ash, and 20.16% total solids in colostrum at 2 h PP, and the respective mean values were 3.55, 4.24, 5.65, 0.87, and 14.31% for regular milk on d 90. A 15-fold increase was shown in fat content during the first 24 h, whereas a sharp decrease was shown during the first 12 h of lactation in protein, ash, and total solids contents. Variation in lactose content was small (4.24 to 4.71%) throughout the study period. Total N, nonprotein N, casein N, and whey protein N were found to be 2.23, 0.06, 0.86, and 1.31 g/100 mL for the colostrum at 2 h PP; and 0.56, 0.04, 0.45, and 0.07 g/100 mL for the milk at 90 d PP. Percentages of caseins increased steadily, whereas whey proteins declined gradually until 3 mo of lactation. Gas liquid chromatography analysis of milk fat showed that the content of even-numbered saturated fatty acids (C12:0-C18:0) in camel colostrum (2 h to 7 d PP) was lower than that of regular milk (15 to 90 d PP). The predominant saturated fatty acids were C14:0, C16:0, and C18:0, regardless of the stage of lactation. There was a considerable level of polyunsaturated fatty acids (mainly C18:1) in Alxa camel's milk fat. The levels of Ca, P, Na, K, and Cl were 222.58, 153.74, 65.0, 136.5, and 141.1 mg/100 g, respectively, at 2 h PP; the values of the minerals were 154.57, 116.82, 72.0, 191.0, and 152.0 mg/100 g, respectively, for the regular milk on d 90. The levels of vitamins A, C, E, B1, B2, B6, and D were 0.97, 29.60, 1.45, 0.12, 1.24, 0.54 mg/L, and 640 IU/L, respectively, in Alxa camel milk at 90 d PP. Vitamin A and C contents were higher and vitamins E and B1 were lower than those in colostrum. Sodium dodecyl sulfate-PAGE and densitometry results demonstrated that Alxa camel colostrum is rich in immunoglobulins, serum albumin, and 2 unknown fractions, which are reduced in amount (%) within 2 d of lactation. It seems that there is lack of beta-lactoglobulin in Alxa camel milk, whereas casein and -lactalbumin start at a low level and increase gradually until they reach their regular levels in the milk.

Camel Milk: An Important Natural Adjuvant

“…The levels of Ca, P, Na, K and Cl were 222.58, 153.74, 65.0, 136.5 and 141.1 mg/100 g, respectively, in colostrum and 154. 57, 116.82, 72.0, 191.0 and 152.0 mg/ 100 g, respectively, in the Bactrian camel milk [123]. The levels of vitamins A, C, E, B 1 , B 2 , B 6 and D were 0.97, 29.60, 1.45, 0.12, 1.24, 0.54 mg/L and 640 IU/L, respectively, in milk.…”

“…Milk fat composition revealed that the ratio of C12:0 to C18:0 saturated fatty acids in colostrum was lower than that of regular milk and the predominant saturated fatty acids were C14:0, C16:0 and C18:0, despite the lactation phase. Considerable level of polyunsaturated fatty acid (C18:1) was also reported in Bactrian milk [83,123]. The composition of fatty acids in Bactrian camel showed slight differences than to dromedary milk.…”

“…The percent value of protein, lactose, fat, ash and total solids in colostrum of Bactrian camel are 14.23, 4.44, 0.27, 0.77 and 20.16%, respectively, whereas in the milk these values were 3.55, 4.24, 5.65, 0.87 and 14.31%, respectively [123]. The percent value of protein, lactose, fat, ash and total solids in Chinese Bactrian camel milk are 3.90, 4.50, 5.32, 0.83 and 14.52, respectively [124] The pH, acidity (%), density, viscosity (mPa s), electrical conductivity (lS/ cm) of regular fresh Bactrian camel milk ranged from 6.37 to 6.57, 0.17 to 0.20, 1.028 to 1.040, 6.79 to 7.16 and 0.380 to 0.547 9 10 4 , respectively [124].…”

“…Camel milk is a rich source of chloride [58] due to the forage eaten by camels such as Atriplex and Acacia, which usually have a high salt content [119] and may be one of the reasons of salty taste of milk [123]. The macromineral content of camel milk varied between breeds, such as Majaheim, Najdi, Wadah and Hamra [77] and Bikaneri, Jaisalmeri and Kachachhi [72,73].…”

Effect of Fortifying Camel Milk with Sheep Milk on the Processing Properties, Chemical Composition and Acceptability of Cheeses

“…The limited ability of camel milk to be coagulated by enzymes is probably due to the composition of casein micelles as the kappa casein, representing the micellar fraction which reacts with the clotting enzymes, has different electro-potential from cow's milk, which causes lower electrophoretic mobility [4]. The low content of kappa-casein and its ratio to total proteins and the lack of ß-lactoglobulins are the main factors that limit cheese making performances from camel milk [9]. On the other hand, the addition of calcium chloride prior to rennet resulted in a reduction in clotting time and improvement in cheese properties [1,7].…”