Microstructure and chemical changes in Karish cheese prepared from reconstituted ultrafiltrated milk

ABSTRACT

Retentate was prepared from reconstituted skim milk by ultrafiltration [UF] and used in Kariesh cheese making. Microstructure and protein hydrolysis in cheese were examined when fresh and after 3 and 6 weeks of ripening. UF cheese had better quality than that made from reconstituted milk by the conventional methods. Protein degradation was more evident in UF cheese resulting in more liberation of free amino acids. The free amino acids released from cheeses, not only differed in their quantitative values but also in their nature and numbers. Thirteen free amino acids appeared in young cheeses then increased to 16 during ripening. TEM and SEM micrographs showed no apparent differences in the microstructure and the fusion of protein particles in both cheese when fresh and during ripening. In Kariesh cheese the fusion of protein advanced more extensively at surface that in the interior body of cheese