Compositional and biochemical changes in Genestoso cheese, a Spanish raw cow's milk variety, during ripening

Physicochemical characteristics, proteolysis and lipolysis were studied throughout the ripening of eight batches of a traditional Spanish variety made from raw cow's milk, in order to establish a basis for its industrial production.

The main compositional characteristics of this cheese after 60 days of ripening were its high proportion of total solids (TS; 752 g kg⁻¹ of cheese), an average content of protein (452.8 g kg⁻¹ TS) and fat (475.1 g kg⁻¹ TS) and the presence of residual lactose (12.5 g kg⁻¹ TS). Its pH value (4.04) was extremely low. Phosphorus (5.13 g kg⁻¹ TS) and sodium (8.29 g kg⁻¹ TS) were the most abundant mineral elements in cheese, whereas calcium levels (1.92 g kg⁻¹ TS) were very low. Proteolysis extension and depth were very low, which resulted in almost zero degradation of αs1- and β-casein. Fat acidity increased during ripening, reaching final values of 50.1 mg KOH kg⁻¹ of fat. The main free fatty acid was C16:0, followed by C18:1 and C14:0.

These results suggest that this variety undergoes a limited proteolysis and moderate lipolysis during ripening. The low pH, low calcium content and limited proteolysis led to a crumbly texture in this cheese variety.