Textural changes and as1-casein breakdown during the ripening of Port Salut Argentino cheese as affected by frozen storage

VERDINI, RA; ZORRILLA, SE; RUBIOLO, AC

JOURNAL OF TEXTURE STUDIES

Blackwell Publishing

Año: 2003 vol. 34 p. 331 - 346

0022-4901

Effect of the freezing process (freezing, frozen storage and thawing) on textural parameters and as1-casein breakdown during the ripening of Port Salut Argentino cheese was studied. Moisture content, salt concentration, casein profiles and asymptotic equilibrium modulus were monitored in control cheeses ripened at 5C and in cheeses frozen, stored at -22C for 30 days, thawed and ripened at 5C, considering different ripening times (1, 6, 13, 27 and 56) and two sampling zones (central and external). The freezing process significantly increased the rate of as1-casein and as1-I-casein hydrolysis. This process may affect the susceptibility of as1-casein to chymosin attack and also the availability of hydrolytic enzymes released by damaged microorganisms, which may contribute to the faster hydrolysis of as1-I-casein. The freezing process did not significantly affect the decay rates of asymptotic equilibrium modulus. First order kinetics constants for decay of the asymptotic equilibrium modulus were 3.71 10-2day-1 (control cheeses, central zone), 8.48 10-2 day-1 (control cheeses, external zone), 4.52 10-2 day-1 (frozen cheeses, central zone), and 11.43 10-2 day-1 (frozen cheeses, external zone). Significant differences in the decay rates of asymptotic equilibrium modulus were found between central and external zones in control and frozen cheeses. The different moisture contents of the sampling zones can be considered as responsible for those differences. Effect of the freezing process (freezing, frozen storage and thawing) on textural parameters and as1-casein breakdown during the ripening of Port Salut Argentino cheese was studied. Moisture content, salt concentration, casein profiles and asymptotic equilibrium modulus were monitored in control cheeses ripened at 5C and in cheeses frozen, stored at -22C for 30 days, thawed and ripened at 5C, considering different ripening times (1, 6, 13, 27 and 56) and two sampling zones (central and external). The freezing process significantly increased the rate of as1-casein and as1-I-casein hydrolysis. This process may affect the susceptibility of as1-casein to chymosin attack and also the availability of hydrolytic enzymes released by damaged microorganisms, which may contribute to the faster hydrolysis of as1-I-casein. The freezing process did not significantly affect the decay rates of asymptotic equilibrium modulus. First order kinetics constants for decay of the asymptotic equilibrium modulus were 3.71 10-2day-1 (control cheeses, central zone), 8.48 10-2 day-1 (control cheeses, external zone), 4.52 10-2 day-1 (frozen cheeses, central zone), and 11.43 10-2 day-1 (frozen cheeses, external zone). Significant differences in the decay rates of asymptotic equilibrium modulus were found between central and external zones in control and frozen cheeses. The different moisture contents of the sampling zones can be considered as responsible for those differences.