Characteristics of Algerian Goat's Milk

Abstract

Goat milk, which is very popular especially in France where many famous cheeses are made, could meet the needs of people living in the mountains, and can be eaten fresh or processed. However, for the latter case, it is established that only milk with α S1-casein expressed with a high percentage could result in the manufacture of cheese. For this, we conducted a study that aims in a first step to assess the physical and chemical characteristics of goat milk collected in three regions of Tizi-Ouzou. The analysis performed has carried on the pH, acidity, total solids, proteins, fat, lactose and vitamin C. The results obtained for these parameters, including total solids (109.3 g / l), fat (30.7 g / l), lactose (39.1 g / l) and proteins (26g / l), are state of the good nutritional value of milk collected locally. However, the levels obtained were below those of bovine milk analyzed under the same conditions. In a second step, we performed the isolation and characterization of proteins. For this, we used the precipitation of the casein at their isoelectric pH (pH 4.2) followed by ion exchange chromatography on DEAE-cellulose. The fractions were then checked by polyacrylamide gel electrophoresis under different conditions (native, in the presence of urea, in the presence of SDS). The resulting electrophoretic profiles have identified similarities between goat and cow milk as they have helped to highlight some particularities including both caseins (αS) as serum proteins (PP3, α-La and β-Lg). The use of weak anionic resin in a single chromatographic separation step is advantageous in that it led to the isolation of goat protein (casein β, casein α S, PP3, SA and β-Lg) with a high degree of purity.