Proteolysis and consistency changes of Gouda and Eidamský blok cheeses during ripening

Composition and rheological and sensory properties of Gouda cheese with different time of ripening (4 weeks, 4, 10, and 14 months) was evaluated. The level of proteolysis was measured by both the determination of nitrogenous compound fractions and the electrophoretic determination of casein proteolysis products. These properties were compared to those determined in Eidamský blok cheese with ripening time of 4 weeks. According to rheological evaluation, cheese hardness increased with ripening time. Sensory evaluation showed that hardness between fingers and in mouth increased and, on the other hand, the elasticity between fingers and in mouth as well as cohesiveness decreased with ripening time because of proteolysis. Based on the intensity sensory evaluations, the salt taste appears more intensive whereas the sour and bitter tastes were less intensive in Gouda cheese. Gouda cheese was evaluated as more pleasant in all three tastes in the hedonic sensory evaluation. The width and depth of ripening increased quite fast in Gouda cheese up to 10 months of maturation. In a four-week old Eidamský blok cheese the slightly lower values of ripening width and depth were obtained. The electrophoretic evaluation showed that the number of identifiable zones rose with ripening time. The growing content of g1-casein, proteose peptone fraction 5, and g2/g3-caseins, which are the products of b-caseins hydrolysis, can be observed as the increase of their zone intensity.