The effect of irradiation and elevated temperature on the ripening of cheddar cheese
| dc.contributor.advisor | Osthoff, G. | |
| dc.contributor.author | Seisa, Dipuo Pascalina | |
| dc.date.accessioned | 2017-11-10T08:43:20Z | |
| dc.date.available | 2017-11-10T08:43:20Z | |
| dc.date.issued | 2001-11 | |
| dc.description.abstract | English: Proteolysis and lipolysis are important biochemical events in the ripening of cheese to contribute to the development of flavour and texture. The characteristic proteolysis of each type of cheese is brought about by the enzymes used in the manufacturing process, e. g. rennet, as well as enzymes from the specific microbial cultures used in each cheese type. The microbial and chemical development can be manipulated by external conditions such as ripening temperature and irradiation. In the current study the effect of temperature together with irradiation on the ripening of Cheddar cheese was investigated. Cheddar cheeses were irradiated after 4 days of ripening at 8 °c and 16°C at a dose of 4kGy and ripening continued up to 12 weeks with unirradiated cheeses ripened at 8 °c and 16°C as controls. In asensorical comparative 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 higher TBA-values. The WSNfTotal N (water-soluble nitrogen /total nitrogen) of the cheese ripened at 8 °c was significantly different than that of the other cheeses after 2 weeks, but then reached the same levels as the treated cheeses after 6-12 weeks. The Urea-polyacrylamide gel electrophoresis of the WISF indicated that the cheese ripened at high temperature matures faster than the cheese ripened at low temperature for both the unirradiated and the irradiated cheeses, whereas the irradiated cheeses showed different peptide development over the same period of ripening. The RP-HPLC of the cheeses indicated a difference in peptide profiles of the unirradiated and irradiated cheese ripened at 16°C, and the irradiated cheese ripened at 8 °c from the unirradiated cheese ripened at 8°C. | en_ZA |
| dc.description.abstract | Afrikaans: Proteolise en lipolise is belangrike biochemiese prosesse in die rypwording van kaas om by te dra tot die ontwikkeling van geur en tekstuur. Die karakteristieke proteolise van elke tipe kaas word te weeg gebring deur die ensieme wat in die verwaardigingsproses gebruik word, bv. rennien, sowel as die ensieme van die spesifieke mikrobiese kulture wat in elke kaassoort gebruik word. Die mikrobiologiese en chemiese ontwikkeling kan beheer word deur eksterne kondisies soos rypingstemperatuur en bestraling. In die onderhawige studie is die effek van temperatuur tesame met bestraling op die ryping van Cheddar kaas ondersoek. Cheddar kase is bestraal 4 dae na ryping by 8 °c en 16°C met 'n dosis van 4kGy en ryping is voortgesit met onbestraalde kase, wat by 8 °c en 16°C rypgemaak is, as kontroles. In "n sensoriese vergelykende studie is kase as nie verskillend in smaak evalueer. Daar was geen betekenisvolle verskille in die vrye vetsuur inhoud van die kase nie, maar die bestraalde kase en kaas wat by 16°C rypgemaak is, het hoër TBA-waardes vertoon. Die water-oplosbare stikstof Itotale stikstof van die kaas wat by 8 °c rypgemaak is, het betekenisvol verskil van dié van die ander kase na 2 weke, maar het dieselfde vlakke bereik as die behandelde kase na 6 tot 12 weke. Die Ureum-poliakrielamied gel elektroforese van die water-onoplosbare fraksie het getoon dat die kaas wat by hoë temperatuur rypgemaak is, vinniger ryp geword het as dié kaas by lae temperatuur in beide die bestraalde en onbestraalde kase, terwyl bestraalde kase ander peptiedontwikkeling oor dieselde rypmakingstyd vertoon het. Die Tru-fase hoe drukvloeistof chromatografie van die kase het 'n verskil in peptied profiele aangedui vir die onbestraalde en bestraalde kase wat by 16°C rypgemaak is, en die bestraalde kaas wat by 8 °c rypgemaak het verskil van die onbestraalde kaas wat by 8 °c rypgemaak is. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/7472 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Lypolysis | en_ZA |
| dc.subject | Proteolysis | en_ZA |
| dc.subject | Enzymes | en_ZA |
| dc.subject | Sensorical | en_ZA |
| dc.subject | Irradiation | en_ZA |
| dc.subject | RP-HPLC | en_ZA |
| dc.subject | TBA-value | en_ZA |
| dc.subject | Free fatty acids | en_ZA |
| dc.subject | Taste | en_ZA |
| dc.subject | Urea-PAGE | en_ZA |
| dc.subject | Cheese -- Microbiology | en_ZA |
| dc.subject | Cheesemaking | en_ZA |
| dc.subject | Dissertation (M.Sc. (Food Science))--University of the Free State, 2001 | en_ZA |
| dc.title | The effect of irradiation and elevated temperature on the ripening of cheddar cheese | en_ZA |
| dc.type | Dissertation | en_ZA |