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Influence of the Coagulant Level on Early Proteolysis in Ovine Cheese‐like Systems Made with Sterilized Milk and Cynara cardunculus
Author(s) -
Silva S.V.,
Malcate F.X.
Publication year - 2004
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2004.tb13653.x
Subject(s) - cynara , casein , chemistry , ripening , food science , proteolysis , pasteurization , cheese ripening , chromatography , hydrolysis , botany , biochemistry , enzyme , biology
The effect of coagulant level on the quality and quantity of protein breakdown during the first 24 h of ripening of cheese‐like systems, manufactured with sterilized ovine milk using crude aqueous extracts of Cynara cardunculus as coagulant, was experimentally assessed. Urea‐polyacrylamide gel electrophoresis was performed on both water‐soluble and water‐insoluble cheese extracts to monitor the casein degradation pattern; the ripening extension index and the ripening depth index were thus calculated. Peptides from the water‐soluble fraction were isolated by reverse‐phase, high‐performance liquid chromatography and partially sequenced by Edman degradation. Higher residual coagulant levels in curdled milk led to earlier breakdown of caseins, as expected. The primary cleavage sites were Phe105‐Met106 in k‐casein, Phe23‐Val24 in α s1 ‐casein, and Leu127‐Thr128, Ser142‐Trp143, Leu165‐Ser166, and Leu190‐Tyr191 in β‐casein.