15C-32 |
Proteolysis of Cheddar cheese manufactured from high-pressure treated milk, microfiltered milk, raw milk, and pasteurized milk during ripening |
P. PANDEY1, H. S. Ramaswamy1, and D. St-Gelais2. (1) Food Science, McGill University, 21111 Lakeshore Rd, Ste- Anne-de-Bellevue, QC H9V3V9, Canada, (2) Dairy Research, Food Research and Development Centre, 3600 Casavant Blvd West, Saint Hyacinthe, QC J2S 8E3, Canada Pasteurization of milk prior to cheese making influences both the extent and characteristics of proteolysis during cheese ripening. Consumer demand for minimally processed, safe, stable food products has stimulated the interest of food researchers in high pressure (HP) processing. The ability of this technology to keep the flavor and natural characteristics of food samples intact provides added advantage over conventional heat processing. However high pressure treatment perturbs the balance of intramolecular and solvent-protein interaction of milk and can, therefore, affect the ripening characteristics of cheese. The objectives of this study was to compare the proteolytic characteristics of cheddar cheese made from HP treated milk, microfiltred milk, raw milk and pasteurized milk during ripening. Cheddar cheeses were made from raw, pasteurized, microfiltred and HP treated milk (60 & 90 min at 300 MPa; 32 & 48 min at 400 MPa). Total nitrogen (TS), water-soluble nitrogen (WSN), and 12% TCA soluble nitrogen were evaluated periodically during ripening for 90 days. The effects of different treatments on cheese ripening characteristics were assessed by ANOVA. Cheddar cheese made from HP treated milk showed a slow rate of proteolysis. Cheddar cheese proteolysis of pasteurized and microfiltred milk were comparable; however, proteolysis rate of raw milk cheese was the highest among all cheeses. Differences in the proteolysis rate among cheeses from HP treated milk were small. However major differences were observed (p<0.05%) between cheeses made from pressure treated milk, raw milk, microfiltred milk and pasteurized milk. Proteolysis in cheese during ripening influences the final quality of cheese and hence an important criteria in cheese making. HP treatment given in this study intended to make the product safe appears to marginally slow down proteolytic activity during the ripening.
Session 15C, Dairy Foods
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