Aplicação de peptidases laticíferas para produção de queijo coalho vegetariano

Abstract

Peptidases are enzymes capable of performing cleavage of peptide bonds of other proteins and peptides. These enzymes exhibit a broad spectrum of applications because they are used from the food industry to the leather and skin processing and drug formulation. Peptidases also have been used in the dairy industry for the cheese production. The coagulation of milk caseins is the main step in the production of the cheese curds. Rennet or renin are consist of chymosin and when added to the milk they cause the first step of forming cheese, the coagulation. Due to restrictions of food intake using animal rennet because of eating habits (vegetarianism) or religious reasons (Judaism and Islamism) the search for coagulating enzymes alternatives to rennet has intensified. The present work aimed to evaluate the caseinolytic and coagulant activities of the milk of five different latex protein extracts for the production of cheese. The latex fractions obtained were dissolved in Tris-HCl 50 mM pH 6.5 buffer and submitted to total proteolytic activity assays with different activators, milk coagulation, total casein hydrolysis, and of κ-casein over time by SDS-PAGE on 15% polyacrylamide gels, establishing a protocol for cheese curd production and detecting peptidases after the production of cheese. Only the fractions of C. procera, C. grandiflora, and C. papaya showed proteolytic activity and milk coagulation activity. These peptidases were activated by DTT and L-cysteine. The milk coagulation time by latex peptidases is dose dependent with 60 µg being the optimum amount to coagulate 2 mL of milk. C. procera and C. grandiflora showed specific activity of milk coagulation close to the commercial rennet of animal origin. High concentrations of NaCl and CaCl2 did not affect the proteolytic activity and coagulation of milk. However, the pre-incubation of these samples at 75º C for 10 minutes completely eliminated their activities. Both proteolytic fractions proved to be capable of hydrolyzing κ-casein and producing peptides of 16 KDa similarly the commercial rennet. The cheeses generated by the latex peptidases had nice flavor, firm texture, scent and yield similar to cheeses produced with commercial chymosin. Also, no proteolytic activity was detected after the production of cheese. This way, the peptidases from C. procera and C. grandiflora can be used as an alternative to chymosin in the production of cheese curds.