Innovative device measures cheese meltability.

You might want to contact researchers at the University of Wisconsin (Department of Agricultural Engineering, 460 Henry Mall, Madison, WI 53706) about a new instrument they've developed to meet cheese industry demands for analytical tests that are fast and are easy to use. The apparatus measures cheese melt parameters more accurately than current methods, yet is relatively simple and inexpensive to use, we're told.

The tool could be valuable for characterizing cheese meltability. The device uses a technique known as lubricated squeezing flow, which eliminates irrelevant data caused by the interaction between the cheese and the interior surface of the instrument. Wisconsin scientists are interested in collaborating with companies to commercialize the device.

The UW-Meltmeter consists of a movable outer cylinder that rises up around a stationary platform to form a well 7 mm deep and 30 mm diameter. To analyze meltability, researchers place a cheese sample with the same dimensions (7 mm by 30 mm) in the well. A 66-mm diameter plate, attached to a linear variable differential transformer, is lowered so that it is flush with the edge of the cylinder and the top of the cheese sample.

The sample is heated to 140 F. The outer cylinder is lowered, and the melted cheese flows as it is subjected to the weight of the top plate. A computer data acquisition system collects rheological data in terms of sample height versus time. The system has been able to successfully discriminate between samples of different melts based on composition, age, pH, and other conditions. Stress and strain rate data are generated and when analyzed, biaxial extensional viscosity can be calculated. By adjusting the weight of the imposed load, you can obtain low strain rates typically experienced when cheese melts on pizza.

Although the test is a bit more complicated than the current Schreiber test used for meltability, and you can't do multiple tests at once, it is more reliable, say the researchers. Because it is computerized, it can provide continuous data, and its results are more comparable to tests taken by others using the same method.

The cheese softening point also can be determined by using a modified procedure. Changes in cheese height and cheese temperature are recorded. When the data are charted, two distinct linear regions appear; the first changes slowly, and the second changes more rapidly. The softening point is the temperature at which the two lines intersect.

Further information. Sundaram Gunasekaran; phone: [phone]; fax: [phone]; email: [e-mail].