To learn about human nutrition. Upon completion of this laboratory exercise, the student will be able to:

1. Name the major classes of macronutrients and list the general functions of each class.

2. List 4 fat soluble vitamins, their functions, and two food sources for each

3. List 9 water soluble vitamins, their functions, and two food sources for each

4. List the recommended servings of foods in an ideal diet referring to the food pyramid

5. Discuss the health benefits of consuming :

    a. alcoholic drinks in moderation

    b. broccoli, cauliflower, and cabbage

    c. tuna fish, salmon, trout

    d. lowfat milk, ice cream and other dairy products

    e. foods made from soybeans

    f. fresh vegetables and fruits

    g. tea

    h. tomatoes, ketchup, and tomato sauce

5. Discuss the harmful effects of consuming:

    a. too much alcohol

    b. too much fat especially saturated fats and cholesterol

    c. too much sugar

    6. Test foods for starch, glucose, and fat content.

Slice of white bread

Slice of raw potato

Several grains of uncooked rice

Cornstarch

Bacon

Sausage

Peanut butter

Tincture of iodine (if you don't have it in your medicine cabinet, you should buy a small bottle at your local pharmacy).

Heat resistant jar

Sugar

Small sauce pan

*Two test tubes

*Test tube holder

*Benedict's solution

Sheet of unglazed paper, such as newsprint or paper towel

Access to a Personal Computer with Internet capabilities

*This item is provided in your lab kit.

Read pages about  nutrition in your text.

Food is what we eat. Nutrients are the substances or molecules we need in our diet. We require macronutrients (carbohydrates, proteins, and fats) and micronutrients (vitamins and minerals) for our cells to function properly. Macronutrients supply structural materials and provide energy. Micronutrients have a metabolic or physiological role.

All three macronutrients can serve as energy sources because they can be broken down into molecules that are combined with oxygen to produce ATP (the energy storing molecule in all cells). The amount of energy available from a given amount of a macronutrient is commonly measured as the number of Calories of heat it yields when fully metabolized. All three classes of macronutrients also provide carbon atoms used by the body to form organic polymers (glycogen, proteins, nucleic acids, etc). In addition, proteins in foods supply amino acids for building the body's own proteins.

All foods provide at least some of our nutritional needs, however not all foods are of equal value. Diet is what foods we choose to eat, and to maintain health we must know what a good diet consists of and choose wisely our food types and quantities. Refer to the figure of the food pyramid in  your textbook (look up food pyramid in index of text) to get an idea of what constitutes a well-balanced diet. These are the Federal Government's Recommended Daily Allowances. Note that complex carbohydrate-rich foods such as bread, cereal, rice, and pasta should make up the bulk of your intake while fats, oils and sweets should only be consumed sparingly.

a. Add 5 drops of iodine to a test tube about 1/4 full of water. Since water contains no starch, this will serve as your control against which you can compare your food tests. Note that there was no color change, you have simply diluted the 5 drops of iodine. The water tests negative for the presence of starch.

b. In a second test tube, mix 1/4 tsp cornstarch with 1/4 tube of water. Shake well to dissolve the cornstarch in the water. Add 5 drops of iodine to the solution. (A purplish, blue-black color indicates the presence of starch.) This solution tests positive for the presence of starch.

c. Drop iodine onto pieces of bread, apple , potato and rice. Also Test egg whites and milk.

a. Add 5 drops of Benedict's Solution to a test tube 1/4 full of water and heat to near boiling. The test tube should be placed in a small jar containing water; and in turn the jar should be placed in a small saucepan containing water. (All this to keep the test tube upright and to be safe; the object is to heat the water in the test tube.) Caution: You can scald yourself if you let the boiling water pop out of the test tube or you spill the hot water. Be careful; and use your test tube holder to lift your hot test tube. There should be no color change; this is your control.

b. Add 1/2 tsp sugar to a test tube 1/4 full of water. Shake to dissolve the sugar in the water. Add 5 drops of Benedict's Solution to the sugar-water solution. Heat in the same manner as discussed in "a" above. Be careful! A yellow, gold, green, orange or brick red color after heating indicates the presence of sugar with orange or red meaning there is a high concentration of sugar, while

green and yellow indicate lesser concentrations. The first tube illustrates a negative test for sugar

and the second illustrates a positive test for sugar.

a. Rub bacon on a piece of unglazed paper, such as newsprint or brown paper from a paper sack.

b. Hold the paper up to the light. (If light comes through a translucent spot on the paper, fat is present.)

c. Do a similar test with potato chips, and a freshly cut potato

Student Name:

Date:

Test Foods For Starch.

Describe the test for starch.

Describe the color of the cornstarch solution before adding iodine.

Describe the color of the cornstarch solution after adding iodine.

Did a color change occur? If so, what did the color change indicate?

Fill in the following chart.

Test for sugar (glucose) in food using Benedict's Solution.

Describe the test for sugar.

Describe the color of water before and after adding Benedict's solution.

Before--

After--

Describe the color of the sugar-water solution before adding Benedict's solution.

After adding Benedict's solution?

After heating?

Did a color change occur after heating the sugar-water Benedict's solution mixture?

If so, what does this indicate?

Test for fat (lipid) in food using unglazed paper.

Describe the test for fat.

Describe the appearance (is it translucent--lets some light through) of the paper after using the:

potato chips--

freshly cut potato--

What food consists of about 10 % protein?

What food consists of over 30 % protein?

Which has more protein--rice or corn?

Refer to Table 26.1 in your text:

Anemia may be caused by a deficiency of what 3 vitamins?

What vitamin is needed for proper clotting of blood?

List the recommended servings of foods in an ideal diet referring to the food pyramid (figure 26.1 in text)

Discuss the health benefits of consuming the following foods and give your sources-- URL, book, magazine, etc.

a. alcoholic drinks in moderation—

b. broccoli, cauliflower, and cabbage--

c. tuna fish, salmon, trout—

d. lowfat milk, lowfat ice cream and other lowfat or nonfat dairy products--

e. foods made from soybeans--

f. fresh vegetables and fruits--

g. tea--

h. tomatoes, ketchup, and tomato sauce--

Discuss the harmful effects of consuming the following and give your sources:

a. too much alcohol

b. too much fat especially saturated fats and cholesterol

c. too much sugar