Submitted to: Journal of Dairy Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/16/2011
Publication Date: 9/1/2011
Citation: Olson, D.W., Van Hekken, D.L., Tunick, M.H., Tomasula, P.M., Molina-Corral, F., Gardea, A. 2011. Mexican Queso Chihuahua: functional properties of aging cheese. Journal of Dairy Science. 94(9):4292-4299. Interpretive Summary: Consumers have very specific expectations when it comes to the quality traits of a specific cheese and are very wary when changes occur in its flavor, texture or functional properties. In the case of Queso Chihuahua cheese, a traditional cheese made from raw milk in northern Mexico, the raw milk cheeses are being replaced by pasteurized versions because of food safety concerns. Pasteurization, a heating process that reduces or eliminates the native microflora and pathogens in raw milk, is known to alter the quality traits of cheese. There is concern that the traditional quality traits that define this cheese will be lost in the pasteurized version. In our study, authentic Queso Chihuahua made with either raw or pasteurized milk were characterized to determine how pasteurization affected the functional properties of the cheese. Specifically, we compared how well the cheeses melted, sliced, and the changes in color upon baking and broiling. Fresh Queso Chihuahua made from either raw or pasteurized milk were obtained from four different cheese makers in northern Mexico at three different times during the year and aged at 4 deg C for up to 16 weeks. Raw milk cheeses had higher melt values and less browning upon heating than the pasteurized versions. Aging also improved the melt and slicing properties of all of the cheeses. Results of this study will help in the development of Queso Chihuahua that has the properties of the traditional raw milk cheeses that are expected by the consumer but with the safety of a pasteurized product.
Technical Abstract: Queso Chihuahua, a traditional, semi-hard cheese manufactured from raw milk (RM) in northern Mexico, is being replaced by pasteurized milk (PM) versions because of food safety concerns and to extend shelf-life. In this study, the functional traits of authentic Mexican Queso Chihuahua made with RM or PM were characterized to identify sources of variation and to determine if pasteurization of the cheese milk resulted in changes to the functional properties. Two brands of the RM cheese and two brands of PM cheese, obtained from four different manufacturers in Chihuahua, Mexico at three different times of the year, were analyzed after 0, 4, 8, 12, and 16 wk of storage at 4 deg C. Color was measured using a colorimeter before and after heating at 232 deg C for 5 min or 130 deg C for 75 min. Meltability was measured using the Schreiber Melt Test on samples heated to 232 deg C for 5 min. Sliceability, the force required to cut through a sample, was measured using a texture analyzer fitted with a wire cutter attachment. Compared to PM cheeses, RM cheeses showed less browning upon heating (broiling and baking conditions), melted more at 232 deg C, and initially required a greater cutting force. With aging, most of the cheeses increased in meltability, decreased in whiteness when measured before heating, and required less cutting force to slice. Seasonal variations were noted among the brands but were not uniform. In addition to proteolytic breakdown that occurred in both RM and PM cheeses as they aged, the differences in the functional properties can be attributed, in part, to the mixed microflora present in the RM cheeses compared to the more homogeneous microflora provided by presence of dairy cultures in the PM cheeses.