chemical composition and micro structure of quark cheese manufactured by standard and by ultrafiltration techniques

ABSTRACT

Quark cheese was manufactured by standard [S] and by ultra filtration [UF] techniques. Chemical composition of skim milk, pre-cheese milk and the gross composition of both type cheeses were determined. Also, free amino acids and microstructure of cheese were investigated. The results show that major differences in the contents of casein, whey proteins [in total protein] and [-SS-] group were observed in UF cheese as compared with S cheese. The levels of amino acids contents were higher in UF cheese than S cheese and level of glutamic acid and NH [3] were present in significant amount in both cheeses. Micrographs [transmission electron microscopy-TEM] of S cheese illustrates that the size of casein micelles is larger continuously of slightly fused micelles, while electron micrographs of UF cheese illustrates smaller micelles