Evaluation of coagulative features from Withania coagulans L. extract on electerophoretic profile of whey proteins and optimizing of coagulation condition in comparison with rennet (chymosin)

Withania coagulans extract has been used for cheese making since ancient times. The aim of this study was to evaluate proteolytic activities of Withania coagulans fruit proteases (WP) in comparison with chymosin for cheese making. Proteases from Withania coagulans fruits purified partially were evaluated on bovine milk substrate. The optimum temperature and pH for WP activities were 70oC and 5.5, respectively. However, chymosin was relatively more sensitive to temperature and the optimum clotting activity of chymosin was at 50°C. Increasing of temperature resulted in an enhancement of the clotting activities for chymosin and WP enzymes, however elevation of pH above 5.5 was unable to affect favorite of clotting quality. Also, addition of various CaCl2 concentrations did not affect on the clotting activity of WP. There was also no significant difference between WP and chymosin for soluble nitrogen and total protein of whey. In addition, electerophoretic protein profile of the whey induced by extract in comparison with chymosin showed no small peptide and this resulted less of bitterness of flavor in produced cheese. The WP enzymes and chymosin gave similar relative activity at different pH values and temperatures for bovine milk substrate, indicating that W. coagulans fruits have potential activity for use as rennet and the fruits could be potential alternative enzymes in cheese making.