Lactococcus lactis subsp. lactis bv. diacetylactis Q5C6 strain as debittering adjunct culture for vegetable clotted cheese

One of the main challenges associated to the use of vegetable coagulants in cheesemaking is represented by the bitter taste conferred to the final product. In this context, the use of aminopeptidases positive strains could lead the hydrolysis of bitter peptides. The present study aimed to setup an experimental cheese clotted by using a kiwifruit enzymatic extract and inoculated with the Lactococcus lactis subsp. lactis bv. diacetylactis Q5C6 strain as debittering adjunct culture. The optimal amount of kiwifruit enzymatic extract, to be used in cheesemaking, was determined by performing laboratory-scale coagulation tests. Two experimental cheesemaking trials (A and B) were performed and the obtained cheeses were subjected to physico-chemical, microbiological, and sensory analysis. Results showed that, compared to cheeses clotted by animal rennet, the use of the kiwifruit enzymatic extract determined changes in fat, ash, and protein content. The L. lactis subsp. lactis bv. diacetylactis Q5C6 strain, inoculated at 1%, was able to reduce the bitter taste obtaining a final product with a sensory profile comparable to cheese clotted by animal rennet.