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Poster D1 Suitability of microfiltered cheese milk in manufacture of Swedish semi-hard cheese
Posters presented at the IDF cheese symposium
571
SESSION D: Future technological trends influencing cheese ripening Poster D1
SUITABILITY OF M I C R O F I L T E R E D CHEESE M I L K IN M A N U F A C T U R E OF SWEDISH S E M I - H A R D CHEESE Elisabeth L i d b e r g The Swedish Dairies' Cheese Research Centre, Tryckeriv~igen 4, S-311 44 Falkenberg, Sweden
& B6rje Bredahl Alfa-Laval Dairy Systems AB, P.O. Box 64. S-221 00 Lund, Sweden
Bactocatch is the name of a milk treatment process that has been developed by Alfa-Laval. The process incorporates microfiltration and sterilization of the retentate and milkfat, which results in a considerable reduction of the bacteria and spore counts of the milk. A high content of anaerobic sporeforming bacteria causes abnormal blowing in the cheese. In 1989, bactocatch microfiltration equipment was evaluated for treatment of cheese milk at the Swedish Dairies' Cheese Research Centre in Falkenberg. The bacteria were concentrated 10 times. About 100 vats of Grev6 cheese 45 + and Herrg~rds cheese 45 + were studied. Experimental cheese made from microfiltered and pasteurized cheese milk was compared to control cheese made from only pasteurized milk. Cheeses were made with or without addition of nitrate to prevent butyric acid fermentation. The study encompassed bacteriological and physical/chemical analyses of milk and cheese, cheesemaking aspects and organoleptic assessment of the cheese. The total number of bacteria measured in the microfiltered and pasteurized cheese milk, compared to raw milk, was strongly reduced by more than 99-9%. The reduction of the number of anaerobic spores was
572
Posters presented at the IDF cheese symposium
also highly significant. Microfiltered and pasteurized cheese milk gave a higher cheese yield. This was mainly due to a higher water content, but the protein yield was also somewhat higher. Differences in the degradation of casein could already be seen after 24 h. The amount of soluble N at pH 4.6 was lower in experimental cheese. In the amount of PTA-N however, there were no differences. The maturation developed at a slower rate in the experimental cheeses than in the controls. After 5 months of maturation, both the soluble N at pH 4.6 and PTA-N content were lower in the experimental cheeses. Despite the differences in the degree of proteolysis, no differences were found either in consistency or flavour. The most important difference between the different milk treatments was, that none of the cheeses made from microfiltered milk and without nitrate addition developed butyric acid fermentation, whereas all Grev~ cheeses made from control milk even with nitrate addition did blow.
Poster D2 L I P O S O M E - E N C A P S U L A T E D N E U T R A S E , F U N C T I O N IN CHEESE M I L K S. Skeie, S. A a m o d t & R. K. A b r a h a m s e n Dept. of Food & Dairy Industries, The Agricultural University of Norway, N-1432 As, Norway
A study of how liposomes behave in cheese milk and in fresh cheese was performed. A renneting experiment with a Formagraph was performed, as well as a simulated cheesemaking procedure, in order to characterize the proteolytic activity during the first 24 h after cheesemaking. Free neutrase, encapsulated neutrase, encapsulated neutrase, treated with a detergent (Triton X-100) in order to free the enzyme, and a phosphate-buffered saline (PBS) as a control, were added to cheese milk. The samples with free neutrase and dissolved liposomes had a significant (0.05%) shorter rennet clotting time (RCT) and their rennet coagulum reached K20 faster than the coagulum of the liposome-encapsulated enzyme and the control. The proteolytic activity in the cheese was measured by Phast electrophoresis. Samples from cheese milk and cheese after 2 and 24 h were analysed. Two hours after cheese making, a new weak band was found after the e and the/~
571
SESSION D: Future technological trends influencing cheese ripening Poster D1
SUITABILITY OF M I C R O F I L T E R E D CHEESE M I L K IN M A N U F A C T U R E OF SWEDISH S E M I - H A R D CHEESE Elisabeth L i d b e r g The Swedish Dairies' Cheese Research Centre, Tryckeriv~igen 4, S-311 44 Falkenberg, Sweden
& B6rje Bredahl Alfa-Laval Dairy Systems AB, P.O. Box 64. S-221 00 Lund, Sweden
Bactocatch is the name of a milk treatment process that has been developed by Alfa-Laval. The process incorporates microfiltration and sterilization of the retentate and milkfat, which results in a considerable reduction of the bacteria and spore counts of the milk. A high content of anaerobic sporeforming bacteria causes abnormal blowing in the cheese. In 1989, bactocatch microfiltration equipment was evaluated for treatment of cheese milk at the Swedish Dairies' Cheese Research Centre in Falkenberg. The bacteria were concentrated 10 times. About 100 vats of Grev6 cheese 45 + and Herrg~rds cheese 45 + were studied. Experimental cheese made from microfiltered and pasteurized cheese milk was compared to control cheese made from only pasteurized milk. Cheeses were made with or without addition of nitrate to prevent butyric acid fermentation. The study encompassed bacteriological and physical/chemical analyses of milk and cheese, cheesemaking aspects and organoleptic assessment of the cheese. The total number of bacteria measured in the microfiltered and pasteurized cheese milk, compared to raw milk, was strongly reduced by more than 99-9%. The reduction of the number of anaerobic spores was
572
Posters presented at the IDF cheese symposium
also highly significant. Microfiltered and pasteurized cheese milk gave a higher cheese yield. This was mainly due to a higher water content, but the protein yield was also somewhat higher. Differences in the degradation of casein could already be seen after 24 h. The amount of soluble N at pH 4.6 was lower in experimental cheese. In the amount of PTA-N however, there were no differences. The maturation developed at a slower rate in the experimental cheeses than in the controls. After 5 months of maturation, both the soluble N at pH 4.6 and PTA-N content were lower in the experimental cheeses. Despite the differences in the degree of proteolysis, no differences were found either in consistency or flavour. The most important difference between the different milk treatments was, that none of the cheeses made from microfiltered milk and without nitrate addition developed butyric acid fermentation, whereas all Grev~ cheeses made from control milk even with nitrate addition did blow.
Poster D2 L I P O S O M E - E N C A P S U L A T E D N E U T R A S E , F U N C T I O N IN CHEESE M I L K S. Skeie, S. A a m o d t & R. K. A b r a h a m s e n Dept. of Food & Dairy Industries, The Agricultural University of Norway, N-1432 As, Norway
A study of how liposomes behave in cheese milk and in fresh cheese was performed. A renneting experiment with a Formagraph was performed, as well as a simulated cheesemaking procedure, in order to characterize the proteolytic activity during the first 24 h after cheesemaking. Free neutrase, encapsulated neutrase, encapsulated neutrase, treated with a detergent (Triton X-100) in order to free the enzyme, and a phosphate-buffered saline (PBS) as a control, were added to cheese milk. The samples with free neutrase and dissolved liposomes had a significant (0.05%) shorter rennet clotting time (RCT) and their rennet coagulum reached K20 faster than the coagulum of the liposome-encapsulated enzyme and the control. The proteolytic activity in the cheese was measured by Phast electrophoresis. Samples from cheese milk and cheese after 2 and 24 h were analysed. Two hours after cheese making, a new weak band was found after the e and the/~