Optimization of flocculation and clotting time of camel milk with camel and goat rennets, and chicken pepsin in comparison with cow milk using response surface method (RSM)

Abstract

To solve the difficulty of coagulation of camel milk, three animal coagulating enzymes: Camel rennet, goat rennet, and chicken pepsin
were used. The study was focused on the optimization of two milk coagulation key parameters: pH and temperature using the response
surface methodology. The cow milk is used as reference. Characterization of the coagulating enzymes extract showed that the protein
content is higher in chicken pepsin [20 ± 0.00 mg/ml] followed by camel and goat’s extracts [15.4 ± 0.00 mg/ml, 8.8 ± 0.00 mg/ml].
However, coagulating and specific activities were more important in camel rennet [111.12 ± 1.23 UP.ml-1, 7.21 ± 0.03 UP.mg-1] than in
goat’s rennet and chicken pepsin. On the other hand, coagulant strength was for camel rennet 1/4166.67 SU, goat rennet 1/2531.64 SU,
and chicken pepsin 1/6153.85 SU. Moreover, results of pH and temperature optimization of camel milk flocculation showed the following
pairs: [X1 = 5.35, X2 = 42] for camel rennet, [X1 = 5.48, X2 = 30] for goat rennet and [X1 = 5.49, X2 = 39.45] for chicken pepsin.
Also, the coagulation showed the following couples: [X1 = 5.37, X2 = 39.09] for camel rennet, [X1 = 5.36, X2 = 38.84] for goat
rennet and [X1 = 5, X2 = 42] for chicken pepsin. The conclusion was flocculation and coagulation optimum points of camel and cow
milk with coagulating enzymes studied are different based on surface plot analysis and the relationship between response and variables