Milk Protein Used to Make Edible, Water-Resistant Film
WYNDMOOR (Montgomery Co.) An Agricul
tural Research Service (ARS) scientist has received a
patent for her method to turn a milk protein into
water-resistant films that could be used to coat or
package foods.
The method removes the protein casein from milk
by using carbon dioxide under high pressure. Casein,
which solidifies when milk is acidified, is the chief
ingredient in cheese. It is also used as a food supple
ment and as an ingredient in nonfood products includ
ing adhesives, finishing materials for paper and
textiles, and paints.
Until now, it’s been difficult to obtain films, fibers,
and molded materials with acceptable mechanical
properties from casein. That’s because moisture can
dissolve casein.
The new extraction method takes advantage of
casein’s natural structure to form water-resisting films
or coatings, according to Peggy Tomasula, the meth
od’s inventor. Tomasula is a chemical engineer at the
ARS Eastern Regional Research Center (ERRC) in
Wyndmoor, Pa.
Jim Core, ARS
Films act as stand-alone sheets, while coatings are
thinner and adhere directly to the product. Both can
act as a barrier to outside substances while protecting
a product from damage or contamination. The new
material remains intact when exposed to water, unlike
water-soluble, protein-based films patented in the
past.
The film can lock in moisture, according to To
masula. Edible coatings might be used to coat dairy
food products such as cheese, or could be used as part
of a laminate in packaging for cottage cheese or
yogurt. Flavorings, vitamins or minerals could be
added to the coating to enhance the flavor and rein
force nutrition. The method could also be used to de
velop biodegradable packaging materials from casein.
Casein may also be combined with plasticizers to
soften and improve the flexibility of casein-containing,
nonfood materials.
In pilot plant studies, ERRC researchers are further
evaluating the method’s potential. The patent is avail
able for licensing, and ARS is seeking commercial
partners. ARS is the USDA’s chief scientific research
agency.