Proteomic study of proteolysis during ripening of cheddar cheese made from milk over a lactation cycle

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Hinz, Katharina
O'Connor, Paula M.
O'Brien, Bernadette
Huppertz, Thom
Ross, R. Paul
Kelly, Alan L.
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Cambridge University Press
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Milk for cheese production in Ireland is predominantly produced by pasture-fed spring-calving herds. Consequently, there are marked seasonal changes in milk composition, which arise from the interactive lactational, dietary and environmental factors. In this study, Cheddar cheese was manufactured on a laboratory scale from milk taken from a spring calving herd, over a 9-month lactation cycle between early April and early December. Plasmin activity of 6-months-old Cheddar cheese samples generally decreased over ripening time. One-dimensional urea-polyacrylamide gel electrophoresis (PAGE) of cheese samples taken after 6 months of ripening showed an extensive hydrolysis of caseins, with the fastest hydrolysis of αs1-caseins in cheeses made in August. A proteomic comparison between cheeses produced from milk taken in April, August and December showed a reduction in levels of β-casein and appearance of additional products, corresponding to low molecular weight hydrolysis products of the caseins. This study has demonstrated that a seasonal milk supply causes compositional differences in Cheddar cheese, and that proteomic tools are helpful in understanding the impact of those differences.
Bovine milk , Lactation stage , Cheese , Proteolysis , 2-DE
Hinz K, O'Connor PM, O'Brien B, Huppertz T, Ross RP, Kelly AL. (2012). Proteomic study of proteolysis during ripening of Cheddar cheese made from milk over a lactation cycle. Journal of Dairy Research, Volume 79, 2: 176-184. doi: 10.1017/S0022029912000027
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