PROCESSING METHODS TO MODIFY THE LEVELS OF BIOLOGICALLY ACTIVE COMPOUNDS IN MILK AND CHEESE
Location: Dairy and Functional Foods
Title: Impact of curd milling on the quality traits of starter-free pasteurized Queso Fresco
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 29, 2012
Publication Date: October 1, 2012
Citation: Van Hekken, D.L., Tunick, M.H., Leggett, L.N., Tomasula, P.M. 2012. Impact of curd milling on the quality traits of starter-free pasteurized Queso Fresco. Journal of Dairy Science. 95(10):5527-5535.
Interpretive Summary: Queso Fresco (QF), a fresh high-moisture Hispanic-style cheese very popular in the Americas, is traditionally finely ground or milled during production to ensure the cheese will crumble easily but the step also increases the risk of microbial contamination. This study was conducted to determine if this traditional step could be eliminated while maintaining the quality properties of the cheese. QF was made using a fine, medium or coarse milling step and the chemical, functional, and textural properties were compared to non-milled QF. Results showed that the milling step had minimal impact on cheese quality traits and manufacturers can omit this step from the QF make procedures. This modification will not only increase the safety of the cheese but may also reduce the cost of the manufacture of this cheese.
Manufacture of Queso Fresco (QF), a high moisture fresh Hispanic-style cheese that is very popular in the Americas, varies from country to country with many manufacturers fine milling the curd prior to forming the cheese block to ensure its crumbly nature. As this traditional step increases the risk of microbial contamination, this study was undertaken to determine if the curd milling step could be omitted without altering the chemical, functional, and textural properties of QF. Starter culture-free, rennet-set QF was prepared from pasteurized, homogenized milk. Curds were cooked at 39C for 30 min, wet salted at 1.45 g NaCl/100 g milk, and chilled prior to being fine, medium or coarse milled and hand-packed into molds. After 12 hr at 4C, the cheese was divided, vacuum packaged, and stored at 4C for up to 8 wks. Fresh QF contained 56.2% moisture, 21.9 % fat, 15.0% protein, 2.6% lactose, and 2.4% salt and had a pH 6.3. Moisture in the non-milled control and salt in all samples were the only components that significantly decreased over the 8 wk of storage and were related to the free serum that collected in the package. Protein and volatile compound profiles indicated that proteolysis and lipolysis were occurring during storage but were not affected by the milling treatments. The milling of the curd had minimal or no impact on the functional and textural properties of QF storage at 4C for up to 8 wk. Results from this study indicate that the milling step can be omitted from the production of starter-free QF made from pasteurized, homogenized milk without altering the expected quality traits of the cheese. This modification will not only increase the safety of this cheese but may also reduce the cost of manufacturing this cheese.