STUDY OF THE MILK-CLOTTING AND PROTEOLYTIC ACTIVITY OF CALF RENNET, FERMENTATION-PRODUCED CHYMOSIN, VEGETABLE AND MICROBIAL COAGULANTS

Coagulation characteristics, clotting time (r), firming rate (K20) and curd firmness (A30) in cow milk treated with calf rennet, proteinase of Mucor miehei (Fromase), fermentation-produced chymosin (Maxiren) an d a vegetable coagulant prepared from Cynara cardunculus have been stu died. K20 of calf rennet was similar to that of the vegetable coagulan t and higher than values obtained for Fromase and Maxiren. All enzymes acted on casein yielding breakdown products ranged in a relative mole cular mass from 25000 to 12000. The vegetable coagulant showed a stron ger proteolytic activity than the other 3 coagulants acting on beta-ca sein and alpha(s1)-casein; the liberation of amino groups was three ti mes greater than by the others coagulants. Bovine serum albumin (BSA), alpha-lactalbumin (alpha-La), beta-lactoglobulin (beta-Lg A and B) an d beta-lactoglobulin A (beta-Lg A) were not hydrolysed by Fromase and fermentation-produced chymosin. On the other hand, the vegetable coagu lant degraded them all except beta-lactoglobulin B (beta-Lg B) over a period of 2 h.