The World of
Mayonnaise ©
There
is a whole science out there devoted to food.
Most people do not know all the neat things that can be learned just
from your jar of mayo. Mayonnaise is one
of the many foods that is referred to as an emulsion. An emulsion is a combination of two unlike
components. The most common combination
of two immiscible, or unlike, components is oil and water. Below are some fun activities and interesting
facts for you and your students as an introduction into food science.
The World of Food Science: Come here to learn
just what food science is and how it affects our daily lives.
What
are Emulsions? All
you need to know about emulsions.
How
Many Emulsions Do You Know? Here
are some foods you probably never know were considered emulsions.
Teacher
Zone: Here a fun
activity you can perform with the class, and some extra information that could
be useful for the classroom.
Links: Some fun links to further your knowledge.
Credits/Citations
Food science and
technology is a science that affects everyday life, which most people are
unaware exists. It concerns the
preservation, improvement, and innovation of old and new food products. It starts with the harvesting of raw food
materials such as carrots and potatoes, and it ends with the consumption of the
canned soup that contains the vegetables.
The headquarters of the about food science and technology committee is
the
IFT ©
Many major well-known companies need food
scientists. Such corporations as Kraft
foods and Coca Cola depend on these individuals for new products that meet the
standards of current consumer trends.
The
10. Your entry into the world’s largest
industry.
9. Lengthy explanations that you’re not
in food service or nutrition.
8. Classes of 20, not 200.
7. You can eat your own experiments.
6. Microbiology, Chemistry, Physics,
etc…We’ve got the sciences covered.
5. No foreign language requirements.
4. How else would you get the cheese in
the combo!
3. Where else do you class credit for
tasting beer and wine!
2. The excuse “my dog ate my homework”
really works!
1. Unlike your mom, we’ll let you play with
your food!
~Courtesy of Dr. Shewfelt and Amy Rowly
According to Ronald C. Deis, “emulsions are defined as mixtures of at least two immiscible liquids” (2002). One very common combination of two immiscible liquids is oil and water. Emulsions consist of a continuous or external phase and of a dispersed or internal phase. The continuous phase surrounds droplets of the dispersed phase, and therefore, emulsions are referred to in this manner. For example, in a product that has water molecules surrounding oil molecules is called an oil in water emulsion (o/w). In foods, the two immiscible compounds usually are oil and water. It is very important that emulsions occur for the quality of food products. Such things as general appearance, mouth feel, and texture are important aspects of food affected by emulsions (Scamen 2005). All of these are major issues for food scientists when formulating a new product.
An emulsion is a type of colloid
dispersion, which is a two-phase compound.
The type of colloid dispersion found in many foods is called a molecular
dispersion. The dispersion is occurs
when the dispersed phase is a type of macromolecules, fats, proteins,
carbohydrates, etc. (Wikipedia 2005).
The study of dispersions and reduction of particle size of the dispersed
phase is a part of food science. The
range of the dispersed phases in colloids is often .001 to 1 micrometer
(Wikipedia 2005).
The determination of the particle size in emulsions depends on the mixing process. There are many different levels of particle size and therefore many options companies can use to create emulsions. For products with larger particles, such as mayonnaise, lower energy machinery can be used like the normal house blender. For more fine particles, larger equipment must be utilized. One example of this process is homogenization. Homogenization is mechanical process that divides particles into micrometers to create a stable emulsion (Wikipedia 2005).
The phases in emulsions can separate from each other after processing. This separation is referred to coalescence. Coalescence occurs because smaller droplets that are closer together start merging into larger particles (Wikipedia 2005). To correct this problem, food scientists use additives called emulsifiers. These additives are “liaisons between two liquids and serve to stabilize the mixture” (HowStuffWorks, Inc. 2005). Lecithin is a common emulsifier found in egg yolk and soybeans. It is a phospholipid, which allows the molecule to bind to polar (water) and nonpolar (oil) chemicals. This is the major emulsifier in mayonnaise.
Interestingly, food scientists are now developing lecithin as a food supplement and for medical uses (Wikipedia 2005). Please refer to http://www.1001herbs.com/lecithin/ for more information.
Mayonnaise is
one of the many emulsions that people are surrounded by everyday. Here is a list of few more that may be
considered emulsions. How many do you
know?
1. Butter or Margarine
2. Latex Paint
3. Salad Dressings
4. Glues
5. Sausage
6. Chocolate Fudge
7. Egg Yolk
8. Milk
9. Baked Goods
10. Condiments
As you can see emulsions are found in all different types of products. It has been said that all foods are emulsions. What do you thing about that? Obviously, emulsions have a great effect on everyone’s lives.
Unfortunately, most students do not
have a basic understanding about the depth of the area of food science before
entering college. This website was
designed for high school students, junior or senior level chemistry, to use as
an induction into the huge opportunities that food science has to offer. Teachers, please help your students to
understand the importance of food science.
Here is a fun
activity to do during class:
Below is a homemade recipe for
mayonnaise. If you prefer, use a
different type of emulsion recipe and modify it to the activity.
First, begin the lecture by
explaining product development, and tell the students the need for the perfect
formulation to create the best product.
Separate the students into groups and give them each a measurement
needed in the recipe. Write the
components of the mayonnaise on the board and explain that each of these
ingredients is in the final product.
Allow the students to discuss and form their own hypothesis of which
ingredient matches which measurement.
Troubleshoot problems with the children to determine the correct
formulation before actually creating the mayonnaise. After the correct formulation is created,
have fun making your own mayonnaise!
RECIPE
Ingredients:
2 egg yolks or you can use egg
substitutes because raw eggs could cause Salmonella poisoning
½
teaspoon powdered mustard
½ teaspoon salt
2 teaspoon vinegar
½ teaspoon sugar
1 cup olive oil which is good,
unsaturated lipids
2 tablespoons lemon juice
Allow ingredients to come to room
temperature. Beat eggs yolks with
electric mixer in a small bowl until they have a lemon color. Beat in mustard, salt, ½ teaspoon vinegar,
and the sugar. Beat in ½ cup olive oil very
slowly (about ½ teaspoon at a time).
Mixture should thicken at this point.
Mix 1½ teaspoons vinegar and 2 tablespoons lemon juice. Alternately add another ½ cup olive oil and
the vinegar-lemon juice mixture, drop by drop, until mayonnaise is thick and
smooth. The acidic mixture is important
because the pH attained helps bound the proteins in the product (Dairy
Management, Inc. 2002). If the dressing
curdles (gets lumpy), beat another egg yolk in another bowl and slowly beat
into curdled product, drop by drop. The
lumpiness is the dispersed phase coming together, therefore that means there is
not enough emulsifier in the product. By
adding more egg, you are ad ding more emulsifier for stabilization. If too thick of mixture, thin using
cream. This adds water-soluble proteins
that will thin out the mixture because they will repel from the nonpolar fat
macromolecules. This makes about 1½
cups.
~Recipe courtesy of my Aunt Annie
Here are some
links to learn more fun facts:
Institute of Food Technologists
"UGA Department of Food Science &
Technology"
Mayonnaise
Information and History
Dairy Management Inc. 2002. Dry
Whey Functional Properties. Do it with Dairy. Retrieved
on
Deis R. C. 2002. Food
Emulsions-Combining Immiscible Ingredients. Food Product Design. Retrieved
on
HowStuffWorks, Inc. 2005.
Retrieved on
Lignin Institute. 2001.
Lingnosulfonate-Stabilized Emulsions. Dialogue (1).
Scamen, C. Emulsifiers and
Stabilizers. Retrieved on
Wikipedia, the Free
Encyclopedia. 2005. Retrieved on