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Lloyd Metzger
Food Science and Nutrition
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The Minnesota State Fair starts in less than two weeks and, because
many Fair food items are made with process cheese, Lloyd Metzger's
research couldn't be more timely. Metzger, an assistant professor
of food science and nutrition, has developed a small-scale manufacturing
system that helps the dairy industry make better cheese.
Process cheese is an important dairy product, with several billion
pounds produced each year in the United States alone. It is unique
as a dairy product because it is manufactured in several forms,
including slices, blocks, sauces, dips, and spreads.
While researchers and manufacturers have been able to control the
flavor of process cheese, they have been less successful in controlling
its texture and melting characteristics. Controlling these characteristics
is critical for meeting consumer expectations for certain types
of process cheese. "When people buy process cheese they expect
certain characteristics: they expect the cheese they use for nachos
will melt and flow, the cheese slice they put on a cheeseburger
will stay on the burger and not fall off onto their plate, and the
cheese inside a breaded cheese stick will stay in the breading and
not leak out," says Metzger.
The difficulty in controlling the texture and melting characteristics
of process cheese is largely a result of the numerous ingredients
and manufacturing conditions used. Cheese manufacturers also find
it challenging and expensive to experiment with these characteristics,
because their huge production systems use thousands of pounds of
ingredients for each batch of cheese.
Through his research, Metzger has developed a small-scale manufacturing
system to measure and evaluate texture and melting characteristics
of process cheese using a piece of equipment called the Rapid Visco
Analyzer (RVA). The RVA is a computer-integrated instrument commonly
used in the cereal and starch industry. It is designed to heat and
cool small samples (approximately one ounce in size) during mixing
while also measuring viscosity. Prior to Metzger's research, the
RVA had not been used in the dairy industry.
"The main ingredient in process cheese is natural cheese (i.e.,
cheddar cheese) and process cheese manufacturers maintain a large
inventory of natural cheese. Unfortunately, this inventory is constantly
changing (i.e., ripening), which causes the characteristics of the
process cheese they are making to change. Consequently, process
cheese manufacturers are continuously adjusting the 'recipe' they
use to make process cheese. The RVA allows them to develop and test
recipe changes," says Metzger. This small-scale system for
process cheese manufacture and analysis allows researchers and product
developers to rapidly determine the effect of numerous formulations
and processing conditions at minimal cost and using a minimal amount
of ingredients.
On September 3, Metzger will display the RVA at the State Fair in
the University of Minnesota building. So while you're eating your
pizza, cheese curds, or nachos, stop by to see what Metzger is doing
to improve the quality of the food you're enjoying.
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