ARS | Publication request: RHEOLOGICAL PROPERTIES OF AGING GOAT'S MILK MONTEREY JACK CHEESES

Submitted to: Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 2, 2004
Publication Date: May 28, 2004
Citation: Van Hekken, D.L., Tunick, M.H., Park, Y.W. 2004. Rheological and proteolytic properties of Monterey Jack Goat's milk cheese during aging. (abstract). Journal of Agricultural and Food Chemistry. (17)52:5372-5377.

Interpretive Summary: Specialty cheeses made from goat's milk have a very devoted and growing customer base in the US. The majority of the goat milk cheeses produced in the US are made by small farmstead operations and the cheesemaking steps can vary from farm to farm. Very little research has been conducted on goat's milk cheeses and, because there are differences between goat and cow wmilks, not all of the information collected on cow milk cheeses can be applied to goat milk cheeses. In order to establish more uniform production and quality standards for goat milk cheeses, basic information on these cheeses when they are first made and as they age must be collected. In this study, quantitative information on the composition, meltability, and textural properties of goat's milk Monterey Jack cheeses over a 6 month aging period was obtained. Significant changes in the properties of the cheese showed a minimum of 8 weeks of aging was required to obtain uniform texture in goat's milk Monterey Jack cheese. This study starts the collection of measured quality traits for goat's milk Monterey Jack cheese that can be used in future quality, processing and aging studies to set up standards, make a more uniform product, and expand the specialty goat's milk cheese industry in the US.

Technical Abstract: Properties of Monterey Jack cheese, made from fresh goat's milk, were characterized over 6 months of refrigerated storage. Analyses were conducted after 1, 4, 8, 16, and 26 weeks of storage at 4C. Cheeses were assayed for degree of proteolysis and meltability. Their rheological properties were determined using torsion, small amplitude oscillatory strain, and texture profile analyses. Over the 26 weeks of storage, the amount of beta-casein decreased significantly with a concomitant increase in its protein fragments. The greatest change in texture was seen within the first 4 weeks of storage and usually stabilized by week 8. As the cheese aged, the internal structure of the cheese matrix became less rigid as shown by increased meltability and decreased hardness, shear stress for failure, and shear rigidity. Viscoelastic properties increased over time as the cheese increased in elastic and viscous moduli and complex viscosity. Texture mapping of torsion data indicated that the cheese became more rubbery as it aged. This study establishes a quantitative database for several quality properties of goat's milk Monterey Jack cheese and provides baselines for future quality, processing, and aging studies.