Factors influencing the gelation and rennetability of camel milk using camel chymosin

The effects of temperature, pH, concentration of camel chymosin and addition of CaCl2 on the hydrolysis of kappa-casein (kappa-CN) and the coagulation kinetics of camel milk were investigated. The rate of kappa-CN hydrolysis was higher at 40 degrees C than at 30 degrees C and with increasing addition of chymosin and decreasing pH. For all samples gelation was initiated at levels of camel milk kappa-CN hydrolysis >95%. The gelation time (T-g) of camel milk was significantly reduced (from 717 to 526 s) at 30 degrees C when the concentration of chymosin was increased, but was independent of chymosin concentration at 40 degrees C. Reducing pH also reduced T-g. The gel firmness increased at 40 degrees C (58 Pa) compared with 30 degrees C (44 Pa) and effect of CaCl2 addition on the gelation properties of camel milk was found to be dependent on pH; a significant improvement was only found at pH 6.3. (C) 2016 Elsevier Ltd. All rights reserved.