Silva, S. V.Malcata, F. X.2011-10-212011-10-212004-08"Journal of Food Science". ISSN 0022-1147. 69:7 (2004) C579-C584http://hdl.handle.net/10400.14/6719The 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 s1-casein, and Leu127-Thr128, Ser142-Trp143, Leu165-Ser166, and Leu190-Tyr191 in β-casein.engPlant rennetRipeningDairy foodHPLCElectrophoresisjournal article