Tasty Tidbits - Food Experiment Solutions
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The following are solutions to the food experiments in the
4-H Foods Project, "Tasty Tidbits" for Pennsylvania. These
have been modified from the Purdue Leader's Guide. Please note
that those questions in the project book that have "no right
answer" or involve personal feelings are not listed in this text.
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1a. Be Cool with Water
1. How long did it take for the plain water to pass through
the filter?
A. Answers vary, but plain water takes less time to pass
through the filter than sugar water.
2. How long did it take for the sugar water to pass through?
A. More time than the plain water.
3. If you think of the coffee filter as your stomach and
kidneys, what would you conclude?
The high amount of sugar in soda, fruit juices, and sports
drinks causes the liquid to be absorbed much more slowly
than plain water. Such liquids do not help hydrate a
thirsty athlete as quickly as possible. Cold water is
best - it absorbs faster - through the stomach to where it
is needed.
Dig Deeper-Hidden Water in Foods
Fresh bread is soft and moist. After toasting, when the bread
is laid on a plate for a few minutes, water accumulates on the
plate. Toasted bread weighs less. A second toasting dries the
bread out even more.
1b. Here Come the Veggies!
3. What nutrients are in your raw vegetable salad?
The nutrients include vitamins (especially vitamin A, C, and
folate), minerals, especially magnesium and iron), water, and
carbohydrates. Vegetables are naturally low in fat and
provide fiber. The salad dressing provides vitamin E.
1c. Better Wedges
1. How do your baked tortilla chips compare with fried?
Comparisons can be based on taste, color, texture (crispness),
and cost.
2. What other ways can you alter the recipe for nachos to lower
the fat? A. Use low-fat cheese.
2a. How Much is It?
Dig Deeper-Larger vs. Smaller Packaging
There is no one right answer. Comparison pricing is necessary
for most items bought in bulk. For example, buying 8 pints
of strawberries at 98 cents a pint is less expensive than buying
half a case (8 pints) at $7.99; the difference is 15 cents. In
general, the largest price discrepancies will be in different types
and sizes of prepared foods.
2d. Make Your Own!-Mixes
There are many mixes you can make like store bought mixes.
Examples include: all-purpose baking mix to make brownies,
pancakes and various cookies; instant oatmeal mix, cake mix,
pudding mix, and gravy mix.
3a. Baking Better Batters
1. Compare the two cakes for flavor, appearance and texture.
If less fat is used, the cake will be slightly drier, less
tender, and have more crumbs than the original recipe. If
less salt is used, the cake may or may not have a detectable
difference in taste. The amount of salt used does not affect
the appearance or texture of the cake.
If less sugar is used, the cake has slightly less flavor and is
less sweet. The texture and appearance change slightly; the cake
is more compact and not as tender as the original cake. The cake's
crust has less color because it is the sugar that browns.
If fewer nuts are used, the texture and appearance of the cake
are only slightly affected. If whole wheat flour is used as
indicated, the cake's texture becomes slightly more dense.
If egg whites are used instead of whole eggs, the cake's flavor
and is affected slightly. The cake's texture is slightly drier and
less tender. The cake is slightly paler in color with-out the egg
yolks. The volume (height) of the cake is not affected because the
volume depends on the egg white.
2. Which ingredient change made the biggest difference?
Substituting the amount of fat used in the recipe gives the biggest
change. That includes the amount of oil and whether whole eggs
or egg whites were used. For some people, sweetness may make a
big difference in the overall acceptability of the cake.
Dig Deeper-Cake Mix with Little Sugar
Sugar gives a cake more flavor, but it also makes the cake tender
and moist because sugar attracts moisture. Sugar also gives a
cake its brown crust because sugar caramelizes when heated. Too
little sugar in a cake gives a pale crust, which has a tougher
crumb, and less flavor.
3b. Twisting Twisty Pretzels.
1. What ingredient is missing from this recipe that breads
usually have. A. yeast.
2. How can you make substitutions for some of the ingredients
in the pretzels if you wanted to eat less fat and salt?
Use only one tablespoon margarine in the dough. Generally,
soft spread margarines are not recommended in baking unless a
recipe calls for them. They should not be used as a substitute
because the baked product will not be the same. The egg in the
recipe is used to brush on each pretzel its brown color and helps
the coarse salt stick to the surface. Eliminating the egg would
eliminate some fat, but would not decrease the amount
significantly. Omit the salt from the dough or use a salt
substitute. Also, use less coarse salt on each pretzel or
eliminate it.
3d. It's So Easy!
4. What kind of advantages do you think a one-dish meal offers?
Easy to prepare, serve and clean-up.
Uses and stretches leftovers; economical
Allows creativity and fun because several different types
of foods, such as beans or meat, milk or cheese, fruits,
vegetables, and grains are combined.
4a. Green Fuzzy Stuff
2. After two weeks, what happened to the fruit in the bread
sack that was stored in the refrigerator?
Nothing--it looks the same but possibly a bit drier.
3. What about the fruit stored in a warm, dark place
Fruits look like blue-green fuzzy balls. It is actually
a colony of millions of microorganisms growing together,
called, penicillius. The mold is the one from which
scientists made penicillin, the medicine that fights
infection when the body is sick.
4. How would you store fruit?
In the refrigerator. Bread can be stored in the freezer.
Cold temperatures slow down the growth of molds and bacteria.
Dig Deeper-Ethylene gas
The rotten apple releases more ethylene gas, causing the rest
of the apples in the barrel to ripen faster than usual, meaning
they also will rot faster than usual.
4b. Make your own yogurt
3. Besides eating the yogurt you made, how can you use the
yogurt in place of other dairy products?
Yogurt can be used instead of milk or cream in gravies,
ice creams; instead of sour cream in dips and dressings, such
as on gyro sandwiches, or as a topping on cheesecake; instead
of ice cream in milk shakes, and instead of mayonnaise or
salad dressing in fruit salads and lettuce salad dressing.
4c. Ripening Cheese with Mold
1. Describe the mold growth you observe:
Fuzzy, threadlike structures extend up from the cheese and
branch into a tangled mess.
2. How does the cheese's consistency change?
The consistency changes over time from firm, to soft, and
eventually runny. This is due to the mold growing on the
cheese and digesting the protein part of the cheese (casein).
Experts consider certain cheeses, such as Brie or Camembert,
to be ripe when the entire cheese has a creamy consistency.
3. What does the cheese smell like? A. Ammonia
4. Why does the cheese smell that way?
As mold grows on the cheese, it breaks down the protein in
the cheese, resulting in the production of amino acids and
ammonia. Mold-ripened cheeses have a very distinctive
ammonia odor.
Dig Deeper
1. What happens to mold-ripened cheese not exposed to air?
The cheese spoils rather than ripens. Oxygen is necessary
in the ripening process. Note: Not all mold ripened cheeses
need as much oxygen as Brie or Camembert cheese do;
Roquefort is an example.
2. Design an experiment to see how refrigeration affects
the rate that mold grows on the cheese.
Keep a set of inoculated cheese samples at room temperature
and a duplicate set in the refrigerator. After comparing the
rate of mold growth, it is easy to see that the refrigerated
cheese did not ripen because cool temperatures slow down the
whole ripening process. Warm temperatures encourage mold
growth. However, once the cheese has ripened, it must be
refrigerated to slow down mold growth; otherwise, the cheese
becomes over-ripe.
4d. Stop that Browning!
2. Which treatment had the greatest effect in preventing
browning after 60 minutes? A. Lemon Juice
3. Why didn't the fruit pieces treated with lemon juice turn dark?
Vitamin C in lemon juice slows down the reaction between the
chemicals in the fruit and the oxygen in the air. Browning is
the result of a reaction between oxygen and a pigment in the
fruit. This process of browning is called oxidation.
Dig Deeper-Fruit Cocktail
To slow the browning of fruit, the following juices can be used:
lime, pineapple, grapefruit, or orange. Other juices, such as
apricot, apple or white grape juice do not have enough Vitamin C
to prevent browning. Commercial products, such as Fruit Fresh,
are available to help prevent browning.
5a. Freezing Batter or Baked Stuff
1. Baked cupcakes generally freeze better than unbaked cupcake
batter.
Cupcake (and cake) batter can be frozen for a short time (1 to 2
weeks) but there will be changes in the volume and texture of the
final baked product. It is more convenient to bake and then
freeze because certain unbaked cakes should not be frozen: angel
food, chiffon, chocolate, fruit, pound, yellow cakes and cheese
cakes.
Baked products must be frozen quickly, because during freezing
moisture in a baked product changes into ice crystals. Slow
freezing causes large ice crystals to form, which can result in
a texture change in the baked product. Quick freezing results
in smaller crystals.
Incorrect thawing may produce a dry, dense product. When thaw-
ing a frozen baked product, it is important to keep the freezer
bag sealed to prevent moisture loss.
Dig Deeper-Baked cupcakes with or without frosting
Cupcakes (and cakes) freeze better without icing or filling.
Cakes with uncooked frosting can be successfully frozen. Cakes
with cooked frostings, whipped cream toppings or egg white
frostings do not freeze well.
5b. What needs blanching?
1. Compare broccoli packages. Which comes closest to the freshest
taste? A. Blanched product has better color and flavor and
firmer texture.
2. If you put the broccoli into a saucepan, cooking and seasoning
it in the way your family usually does, can you taste the
difference?
Yes, because of off flavors, discoloration, and toughness
cannot be corrected by seasonings.
5d. Going Bananas!
1. How are your dried banana chips similar or different than the
ones you froze?
Dried banana chips are crispy, yellow, thinner and smaller than
the undried original slice and can be packaged to eat anywhere.
Frozen banana chips are: creamy, whitish, same size as the
original, but must remain frozen.
Dig Deeper-Reconstituting a dried banana chip, how long would it
take for the water to rehydrate the banana slice.
A. Rehydrates in minutes. Drying required 2-3 hours.
6a. Check it Out!
1. What was the biggest difference in the two batches of potatoes
you fried?
A. Color. Refrigerated potatoes produced fries that were
darker (browner), less crispy, and with a brown or burnt
flavor compared to the potatoes that were not refrigerated.
2. Describe the taste of both fried potato batches.
A. Refrigerated potatoes produced fries with an almost smoky,
burnt taste. Unrefrigerated potatoes produce normal
tasting fries with a pleasing potato flavor.
3. What happened to the potato stored in the refrigerator?
A. During refrigeration, complex carbohydrates (starch) in
the potatoes change into simple carbohydrates (sugar).
Sugar burns easily at high temperatures (frying).
Commercial french fries are "sprayed" with a dilute sugar
solution so there is some light brown color on the fries.
4. What recommendations would you make to the food company about
storing potatoes?
A. Potatoes should be stored unrefrigerated.
Dig Deeper-Potatoes Brought to Room Temperature after Storage
Refrigerated potatoes brought to room temperature still contain
sugar so they will brown when fried just as easily as when they
were fried from a refrigerated state. Commercially frozen french
fries are generally darker than homemade fries. If different
brands of fries were investigated, results will vary by brand name.
6b. Map Your Taste Buds
1. Which taste was the most difficult to identify?
A. Sour and salt are often confused.
2. Which part of your tongue was the most sensitive to different
tastes? Least?
A. The most sensitive is at the tip and the sides. The least
sensitive in the middle of the tongue.
3. Where on your tongue were you able to detect whether two tastes
overlapped?
A. Sweet and salt are best sensed at the tip of the tongue.
Dig Deeper-Salt on grapefruit, melons and cantaloupes.
For many people, the salted grapefruit half tastes sweeter. If the
fact that there is salt on the grapefruit hampers some tasters,
blindfold the taster and ask which grapefruit tastes sweeter.
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Updated 8/15/05