Short communication: Caseins and α-lactalbumin content of camel milk (Camelus dromedarius) determined by capillary electrophoresis

Abstract

Camel milk has unique physical, nutritional, and technological properties when compared with other milks, especially bovine. Because proteins confer many of the properties of milk and its products, this study aimed to determine the proteins of camel milk, their correlations, and relative distribution. Raw milk samples were collected from 103 dromedary camels in the morning and evening. Capillary electrophoresis results showed wide variation in the concentrations (g/L) of proteins between samples as follows: α-lactalbumin, 0.3 to 2.9; α S1 -casein, 2.4 to 10.3; α S2 -casein, 0.3 to 3.9; β-casein, 5.5 to 29.0; κ-casein, 0.1 to 2.4; unknown casein protein 1, 0.0 to 3.4; and unknown casein protein 2, 0.0 to 4.6. The range in percent composition of the 4 caseins were as follows: α S1 , 12.7 to 35.3; α S2 , 1.8 to 20.8; β, 42.3 to 77.4; and κ, 0.6 to 17.4. The relative proportion of α S1 -, α S2 -, β-, and κ-caseins in camel milk (26:4:67:3, wt/wt) differed from that of bovine milk (38:10:36:12, wt/wt). This difference might explain the dissimilarity between the 2 milks with respect to technical and nutritional properties.

Effects of Pasteurization and High-Pressure Processing of Camel and Bovine Cheese Quality, and Proteolysis Contribution to Camel Cheese Softness

“…Figure 3 shows that except for the HTST cheese, the fat, protein, and total solids contents were significantly higher in bovine milk cheeses than camel milk cheeses (p < 0.001), which is in agreement with previous findings (69,70). This can be related, at least partly, to the higher level of κ-casein in bovine milk (47). κ-Casein is known to enhance the coagulation properties by forming a denser casein matrix, which reduces the loss of fat and protein to the whey (27,71).…”

“…There is a major difference between camel milk and bovine milk caseins. Camel milk caseins consist of α-s1, (22.0%), α-s2, (9.5%), β, (65.0%), and κ (3.5%) whereas bovine milk caseins consist of high percentage of α-casein (38%) followed by 36–39% β-casein and 13% κ-casein ( 47 ). Milk κ-casein is the major player in cheese quality because coagulation is initiated when the enzyme chymosin cleavages κ-casein to para-kappa-casein and caseinomacropeptide.…”

“…Bovine milk cheeses had significantly higher textural properties than camel milk cheeses except for cohesiveness ( Table 2 ), which can be explained by the higher content of β-casein with a sticky hydrophobic C-terminal in camel milk ( 47 ). The LTLT-treated bovine milk cheese showed improved hardness, gumminess, and chewiness.…”

“…The observed proteolysis may result from the action of two proteolytic enzymes; the residual chymosin used in milk coagulation or the indigenous milk proteinase, plasmin (EC 3.4.21.7) ( 72 – 76 ). The recombinant camel chymosin used in this study is known to hydrolyze bovine and camel κ-caseins at different positions, Phe105-Met106, and Phe97-Ile98, respectively, leading to the release of different macro peptides ( 77 ) and possibly fewer hydrolysis products in camel milk because κ-casein is present at very low concentration (3.5%) compared to bovine milk (about 13%) ( 47 ). It reported that cheese coagulation by chymosin is slower and weaker in camel compared to bovine milk ( 3 ) but the mechanisms behind these differences are still not known.…”

HPLC Identification of Mare’s Milk and Its Mix with Cow’s Milk

“…1) Для идентификации видовой принадлежности молока различных видов копытных животных удобно использовать сывороточные белки. Благодаря межвидовым различиям в первичной структуре β-лг, α-ла и сывороточного альбумина их физико-химические свойства будут существенно различаться [27][28][29][30].…”