Optimization of Clotting Donkey Milk Using an Aspartic Protease fromCynara Cardunculus Flowers

Abstract

Donkey’s milk is an interesting commercial product, due to its high nutritional value, and can be considered as a suitable source of food for human consumption. For the first time, it was performed the optimization study of clotting process using donkey milk and a plant aspartic protease-cyprosin, obtained from Cynara cardunculus flowers. An experimental design was used for the preliminary factors selection such as: the clotting enzymes (cyprosin and microbial rennet), CaCl2 concentration (0.01%-0.1% (w/v)) and clotting temperature (32-35oC). The cyprosin and the 0.1% (w/v) CaCl2 concentration, as well as the relation between the CaCl2 concentration and the temperature, were the factors that showed a significant influence on the clotting activity. The 0.1% (w/v) CaCl2 concentration is an important factor because allows to obtain a more consistent curd, while the clotting activity of cyprosin was more efficient than microbial rennet. This preliminary study can give a new research base to obtain different types of cheeses using other milk origin as well as different clotting enzymes such as the cyprosin.