Restriction lift date: 2021-09-01
Patterns of proteolysis in Danish blue, Camembert, smear-ripened and Cheddar cheeses
University College Cork
Patterns of proteolysis in Danish blue, Camembert, smear-ripened and Cheddar cheeses The overall aim of this thesis was to investigate patterns of proteolysis in Cheddar, Danish blue (normal and treated), Camembert and smear ripened cheeses at different stages of ripening. Proteolysis in Danish blue was studied during 9 weeks of ripening, specificities of Penicillium roqueforti proteinases on the caseins in milk hydrolysates were determined with a total of 91 and 118 cleavage sites identified in s1- and -casein, respectively. Proteolysis in an Irish farm-house Camembert cheese was studied during 10 weeks of ripening, specificities of Penicillium camemberti proteinases on the caseins in milk hydrolysates were determined and 64, 6, 28 and 2 cleavage sites were identified in s1-, s2-, - and -casein, respectively. Proteolytic, physico-chemical and lipolytic properties of Danish blue cheeses made from partially (73%) or fully homogenised milk (200 L) with or without whey cream were determined at 4 weeks and 8 weeks of ripening. The study showed that incorporation of the whey cream did not cause any major difference to the compositional, proteolytic or lipolytic properties of Danish blue cheese. Proteolysis in an Irish farmhouse smear-ripened cheese was studied by serial slicing (0.41 mm/slice) the first 2 cm from surface towards the center of the cheese. Peptides produced at depths 0.41 mm and 20.5 mm were 720 and 427 from αs1-casein; 691 and 337 from αs2-casein; 807 and 453 from-casein; 180 and 109 from -casein, respectively. The study confirmed higher proteolytic activity at the surface due to action of enzymes of the smear microbiota than at the center of the cheese. Secondary proteolytic changes of the chymosin-derived peptides s1-CN (f1-23) and -CN (193-209) were investigated in Cheddar cheeses made using single strains of Lactococcus lactis subsp. cremoris HP and SK11 during 6 months of ripening and proteolytic specificities of the cell-envelope proteinases of these strains on the caseins were determined. A large number of peptides were identified from mass spectrometric analysis of the soluble extracts of the individual cheesees and highest values of relative intensity from the mass spectrometric analyses were used to plot the cleavage sites that can be used for further understanding of peptides, cleavage site and similar research.
Proteolysis in cheese , Patterns of proteolysis during ripening of cheese
Mane, A. S. 2020. Patterns of proteolysis in Danish blue, Camembert, smear-ripened and Cheddar cheeses. PhD Thesis, University College Cork.