The last time I was at my parents’ house, my dad jokingly
made a reference to “cow lips” in hot dogs.
I had to cringe. With labeling requirements that reveal all ingredients in food products, why does the myth of hot dogs being made of "unspeakable" animal parts still exist? Its longevity
may be due to a hot dog’s inner appearance.
The springy, smooth, reddish brown hot dog is a far cry from marbled,
fibrous beef chuck. However,
that beef chuck can be turned into a hot dog with the right machinery,
ingredients, and cooking process and still deliver the protein, iron, and other nutrients promised by a fresh cut of beef. In a
previous post, I explained the non-meat ingredients of a hot dog. Today, let’s talk about the meat.
A hot dog is an “emulsified” meat product. An emulsion is a stabilized mixture
of solid particles dispersed throughout a liquid component (Aberle, Forrest,
Gerrard & Mills, 2001). In an
emulsified meat product, the particles are fat and the liquid component is
water containing salts and proteins (Aberle et al., 2001). While water and fat would naturally not mix
together, proteins with both hydrophobic (“water-fearing”) and hydrophilic (“water-loving”)
parts can hold the fat and water together (Figure 1).
Myofibrillar proteins (the stringy, fibrous muscle proteins that allow
for movement) hold fat and water together well, but for the myofibrillar
proteins to be of use, they must first be extracted from their original positions
in skeletal muscle. A bowl chopper (think of a king-size food processor) will first dice ground lean meat into tiny pieces, thereby increasing the surface area of the meat. Salt will extract the tightly bound myosin
and actin from each other, and these liberated proteins will then interact with the
fat and water which are later added to the mix (Aberle et al., 2001).
Figure 1: Proteins coat fat particles to allow the fat to be held within the water phase of an emulsified product.
If you are unfamiliar with proteins and how they are put
together, this might be a little confusing.
The main point, though, is that parts of the animal with LOTS of
myofibrillar protein (i.e., skeletal muscle) can interact with water and fat
much better than parts of the animal with little myofibrillar protein. Another type of animal protein is called “stromal
protein,” perhaps better known as “connective tissue.” The main stromal proteins are collagen and
elastin. Collagen is found in skin,
lips, ligaments, bones, and blood vessels, and is, in fact, the most abundant
protein in an animal’s body (Lodish, Berk, Zipursky, et al., 2000). However, it is an “insoluble” protein,
meaning it is not broken down as myofibrillar proteins are broken down by
salt.
Now, you might be wondering, “What does this have to do with
hot dogs?” Remember that hot dogs are
emulsified products, and the emulsion can only be stable if the components bind
together well under stress. Meats that
have high binding capabilities are those high in myofibrillar proteins such as
bull and cow meat, skinless poultry meat, lean pork trimmings, and beef chucks
(Aberle et al., 2001). Meats with a high
percentage of stromal protein include the infamous “filler meats:” lips,
stomachs, snouts, skin, and tripe (Aberle et al., 2001). If hot dogs contain a large percentage of
collagen-rich meat, the collagen will melt during heat processing and then
congeal as gelatin when the hot dogs are cooled (Aberle et al., 2001). These hot dogs will undoubtedly not be what
the producer or consumer wanted. Since skeletal muscle already contains some collagen due to the presence of blood vessels and connective tissue (Figure 1), deliberately increasing the amount of stromal protein by adding lips or snouts is not greatly practiced.
Hopefully you now understand why the joke of “cow lips” in
hot dogs is not so funny. Producers want
their customers to be happy with tasty, nutritious, good looking products, and
this can only happen with the right ingredients. If you are still curious about what’s in your
hot dogs, check the ingredients label.
All filler or “variety meats” must be declared on the label, including
the specific meat’s name (e.g. “heart”) (National Hot Dog & Sausage
Council, 2013). So the next time you’re
at a weenie roast and someone doesn’t want to eat something made of the “less
savory parts of an animal,” show them the ingredient list and enlighten
them! You can even whip out words like "emulsified" or "myofibrillar" to really impress them.
References
Aberle, E.D., Forrest, J.C., Gerrard, D.E. & Mills,
E.W. (2001). Principles
of Meat Science (4th ed.).
Dubuque, IA: Kendall/Hunt Publishing Company.
Lodish, H., Berk, A., Zipursky, S.L., et al. (2000). Molecular
Cell Biology (4th ed.). New York, NY: W. H. Freeman.
National Hot Dog & Sausage Council (2013). How hot
dogs are made: The real story.
Retrieved from http://www.hot-dog.org/ht/d/sp/i/38597/pid/38597.
emulsion diagram: http://lpoli.50webs.com/Tips.htm
.
