Comparative study of milk clotting activity of crude gastric enzymes extracted from camels’ abomasum at different ages and commercial enzymes (rennet and pepsin) on bovine and camel milk

Coagulation of camel milk for the production of cheese has been proved to be difficult by the use of the available commercial rennets, chymosin and pepsin. Therefore this study focused on the use of crude gastric enzymes extracted from the abomasum of camels (Camelus dromedarius) at different ages (1, 3 and 9 years old). The non-purified gastric enzyme extracts from camels (GEC) at different ages were characterized for their protein content, clotting and proteolytic activities and were also compared with those of bovine rennet and pepsin. The conditions of milk clotting by the GEC were optimized at different pHs 5.8, 6.0, 6.3, 6.6 and temperatures 30, 37 and 42°C. The flocculation time of bovine and camel milk by all the enzymes studied were reported. The data showed that the GEC from the older camels gave the best results significantly (P ≤ 0.05) for both milk clotting activity and flocculation time of both bovine and camel milk compared with the other tested enzyme preparations. The optimum flocculation time was obtained at pH 5.8 and 42°C for the camel milk and at pH 6.0 and 37°C for bovine milk.