INVESTIGADORES
SIHUFE Guillermo Adrian
congresos y reuniones científicas
Título:
Primary protein degradation of Fynbo cheese at different ripening temperatures
Autor/es:
SIHUFE G. A.; ZORRILLA S. E.; RUBIOLO A. C.
Lugar:
Anaheim (USA)
Reunión:
Congreso; IFT; 2002
Institución organizadora:
IFT
Resumen:
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Various biochemical changes occur during cheese ripening, such as
proteolysis, that contribute to the development of characteristic flavor and
texture. Temperature is an important factor that affects biochemical processes
during ripening. Moreover, increasing the temperature has proved to be useful
for accelerating the ripening, but cheese quality can be affected.
Our objectives were to study primary casein degradation of Fynbo cheese
at different ripening temperatures and determine characteristic kinetics
parameters.
Twenty-one Fynbo cheeses (12
cm diameter x 6 cm height, initial composition: 50% w/w
moisture, 16% w/w fat, and 30% w/w protein) were brought from a factory and
salted for approximately 10 hr at 12°C
in a solution of 190 g/L NaCl. Cheeses were ripened at 5, 12, and 16°C and sampled at 1, 5, 10,
20, 30, 60, and 90 days. Two different zones (central and external) were
considered because salt and moisture change with cheese position and may affect
proteolysis. Primary casein degradation was studied by urea-polyacrylamide gel
electrophoresis (PAGE). Quantitative analysis of electrophoretic fractions was
performed by scanning photographs at 632.8 nm.
Different casein fractions were considered in a basic electrophoretic
pattern (as1, as1-I and b caseins). Significant
differences were observed between levels of proteolysis for different
temperatures and cheese zones. Casein degradation was major for higher
temperatures and central zone. Results showed that b-casein in Fynbo cheeses was
more resistant to proteolysis than as1-casein,
remaining practically constant during the first month of ripening. Considering
first-order kinetics for as1-casein
degradation, the kinetics constants values were in the range of 0.2 to 2 x 10-2
day-1 (r>0.86). The activation energy for this reaction was
approximately 28 Kcal/gmol.
These results indicated that ripening temperature accelerate
significantly the primary proteolysis of Fynbo cheese and can be useful information
for controlling and optimizing the ripening temperature.