Submitted to: Meeting Abstract
Publication Acceptance Date: July 2, 2004
Publication Date: August 1, 2004
Citation: Van Hekken, D.L., Tunick, M.H., Tomasula, P.M., Molina-Corral, F.J., Gardea, A.A. 2004. Effect Of Aging On The Proteolytic And Rheological Properties Of Mennonite-Style Cheeses From Chihuahua, Mexico. American Dairy Science Assn. Annual Mtg. Paper T287.

Technical Abstract: The proteolytic and rheological properties of semi-hard Mennonite-style cheeses, made from raw or pasteurized milk, were measured over 16 wk of 4°C storage to evaluate the changes that occurred during aging. Samples, obtained from four different Chihuahua cheese manufacturers (two used raw milk and two used pasteurized milk), were collected within days of manufacture and stored. Degree of proteolysis (SDS-PAGE) and rheological (small amplitude oscillatory strain, torsion, and texture profile analyses) properties of the cheeses were measured at 4 wk intervals. Over the 16 wk of storage, cheeses made with raw milk produced sufficient gas to disrupt the cheese matrix and severely limit shelf life. The loss of textural integrity in raw milk cheeses was reflected in the greater rate of proteolysis (decrease in alpha S1- and beta-casein with concomitant increase of casein fragments with molecular mass of 22-18 kDa and <14 kDa) and the decrease in shear strain at the point of fracture (ability to withstand deformation). Shear strain of the pasteurized milk cheeses increased with age. While the hardness, cohesiveness, chewiness, and shear stress and rigidity at the point of fracture of all cheeses decreased over time, these properties decreased more rapidly and tended to be lower for the raw milk cheeses than the pasteurized milk cheeses. Results indicate that proteolysis and shear strain are good indicators of differences in the cheese matrix between the aging raw milk and pasteurized milk cheeses.