The effect of irradiation and elevated temperature on the ripening of cheddar cheese

[摘要] English: Proteolysis and lipolysis are important biochemical events in the ripening ofcheese to contribute to the development of flavour and texture. Thecharacteristic proteolysis of each type of cheese is brought about by theenzymes used in the manufacturing process, e. g. rennet, as well as enzymesfrom the specific microbial cultures used in each cheese type. The microbialand chemical development can be manipulated by external conditions such asripening temperature and irradiation. In the current study the effect oftemperature together with irradiation on the ripening of Cheddar cheese wasinvestigated. Cheddar cheeses were irradiated after 4 days of ripening at8 °c and 16°C at a dose of 4kGy and ripening continued up to 12 weeks withunirradiated cheeses ripened at 8 °c and 16°C as controls. In asensoricalcomparative study, the cheeses were evaluated as not being different in taste.There were no significant differences in the free fatty acid content of the cheeses but the irradiated cheeses and cheese ripened at 16°C had higherTBA-values. The WSNfTotal N (water-soluble nitrogen /total nitrogen) of thecheese ripened at 8 °c was significantly different than that of the othercheeses after 2 weeks, but then reached the same levels as the treatedcheeses after 6-12 weeks. The Urea-polyacrylamide gel electrophoresis ofthe WISF indicated that the cheese ripened at high temperature maturesfaster than the cheese ripened at low temperature for both the unirradiatedand the irradiated cheeses, whereas the irradiated cheeses showed differentpeptide development over the same period of ripening. The RP-HPLC of thecheeses indicated a difference in peptide profiles of the unirradiated andirradiated cheese ripened at 16°C, and the irradiated cheese ripened at 8 °cfrom the unirradiated cheese ripened at 8°C.

[发布机构] University of the Free State