Enhancing cheese yield and milk clotting efficiency with pineapple bromelain enzyme through response surface methodology

Abstract

The high demand for cheese products has impacted rennet enzyme production as the availability of ruminant stomachs becomes less and less limited. Therefore, the plant-based enzyme was the potential solution as an alternative to an animal-based enzyme. Bromelain enzyme is chosen due to its ability to coagulate milk as a proteolytic enzyme. This study aimed to obtain the optimum milk clotting activity (MCA) and yield of soft cheese by bromelain using response surface methodology (RSM) and to evaluate the proteolysis properties of soft cheese. Experimental design was generated using RSM by MINITAB software version 15 with three selected variables including bromelain concentration (0.2-1%), incubation time (1-5 hrs) and incubation temperature (45-55℃). The optimum condition for MCA and yield of soft cheese was achieved at a bromelain concentration of 0.53%, incubation time of 2.33 hrs and incubation temperature of 54.2℃, with predicted MCA and yield of 60.81 SU/mL and 29.88%, respectively. The optimum condition was verified with the MCA and the yield obtained was 60.16 SU/mL and 32.06%, respectively. Since there was no significant difference (p>0.05) between the predicted and verified MCA and yield values, thus it indicates that the predicted optimum condition by RSM can be accepted. The proteolysis of soft cheese produced using bromelain enzyme at optimum conditions was also evaluated and compared with commercial soft cheese. The result of proteolysis showed that proteolysis products such as alpha (α), beta (β) and kappa (κ) casein were visible at molecular bands of 30 kDa for all cheese samples. In conclusion, the bromelain enzyme from Josapine pineapple peel has a potential for rennet alternative with a significant value of MCA and yield and expected product of proteolysis.