| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4565389 | LWT - Food Science and Technology | 2006 | 7 Pages |
Casein and whey protein fractions of milk obtained from 47 ewes of five breeds or crossbreeds (Awassi, Merino, East Friesian×Merino, Awassi×Merino and Awassi×East Friesian) were analysed by capillary electrophoresis (CE). The experiments were performed on a Beckman P/ACE™ system 5510 with an uncoated fused-silica capillary and a low pH buffer containing urea and a polymeric additive. The four major caseins (αs1-, αs2-, β- and κ -casein) in an acid precipitate were well separated, as were the two whey proteins, αα-lactalbumin (α-La) and β-lactoglobulin (β-Lg). The electromigration of the proteins was in the order of α-La, β-Lg, αs2-CN, αs1-CN, κ-CN and β -CN. The milk samples were composed of the same variant of αα-La and two different genotypes (A and B) of β-Lg while the β-Lg AB genotype was evident in the milk of some animals. The αs1-CN fractions displayed considerable heterogeneity with at least 4 different peaks, representing 4 different variants. A fifth peak, corresponding to the Welsh variant (or αs1-CN D), was present in 90% of the ewes’ milk samples. The κ-CN fraction was resolved as a single peak, while the β-CN revealed significant heterogeneity with 3 variants. It appears that the presence of the αs1-CN Welsh variant in Merino ewe and its crosses with Awassi and East Friesian ewes adversely affected milk composition and yield.
