Table of Contents
The purpose of this experiment was to determine the sugar composition of various brand name apple juices, unknown brand apple juices, and juice blends. Then use that information to calculate the percentage of each kind of juice in the blends and compare the name brand apple juices to the unknown brands of apple juice to see if they are labeled truthfully.
I became interested in this idea while looking through a list of ideas provided by my science teacher. The sugar content interested me and since our town produces so many apples, I chose apple juice. I got the idea of truth in labeling and juice percentages while discussing this idea with my science teacher.
The information gained from this experiment will help consumers to know if the manufacturers are labeling their products correctly.
My hypothesis is that in the studied juice blends, there will be a higher percentage of apple juice than any of the other fruit juices present. Additionally, I hypothesize that all the brands of pure apple juice will be labeled accurately and correctly.
I base my hypothesis on the Fair Packaging and Labeling Act, which states that it is "required that the label on each package of a consumer commodity bear, in case such consumer commodity consists of two or more ingredients, the common or usual name of each such ingredient listed in order of decreasing predominance." It also states that "The following acts and the causing thereof are prohibited: The adulteration or misbranding of any food, drug, device, or cosmetic in interstate commerce."
The constants in this study were:
-the same methods of testing
-the same equipment
-all of the juices were 100% fruit juice
The manipulated variable was the analysis of the presence of 100% apple juice in samples of juice from six different manufacturers.
The responding variable was the presence and composition of sugar compounds associated with 100% apple juice.
To measure the responding variable I used a refractometer, which measures the percent of juice that is sugar, in Brix. I also used a high pressure liquid chromatograph, which shows the amount of each kind of sugar in a liquid, in grams per 100 milliliters.
Quantity Item Description
5 mL of the following nine juices:
-Martinelli's Apple Juice
-Juicy Juice Apple Juice
-Washington's Natural Apple Juice
-Seneca Apple Juice
-Minute Maid Apple Juice
-Tree Top Apple Juice
-Tree Top Apple Raspberry Juice
-Tree Top Apple Grape Juice
-Tree Top Apple Pear Juice
1 Pair of Scissors
9 HPLC Vials
9 HPLC Vial Lids
9 Disposable Glass Pipettes
1 Pipette Bulb
1 Carousel
1 High Pressure Liquid Chromatograph
9 Straws
1 Automatic Refractometer
High Pressure Liquid Chromatograph:
1. Go to the store and buy all juice.
2. Go to the lab and gather all materials.
3. Label all the juice with numbers.
4. Label all the HPLC vials with the corresponding numbers.
5. Open the first juice and use a glass pipette to fill the HPLC vial
about 2/3 full of juice.
6. Get a new glass pipette and repeat step 5 for the remaining eight
juices.
7. Screw the lids on the HPLC vials and put them into the carousel.
8. Put the carousel into the High Pressure Liquid Chromatograph
and push start.
Refractometer:
1. Stick a straw into the juice, clamp thumb over the end of the straw
and pull it out.
2. Bring the straw over the refractometer and take the thumb off the
end of the straw (juice should drip out).
3. Push Run and record the data.
4. Clean off the refractometer with Kimwipes®.
Get a new straw and repeat steps 1-4 for the rest of the juice.
Introduction
Did you know that a tree needs 50-60 leaves to provide enough nutrients for one apple? Did you know that according to botanists a berry isn't really a berry at all? In this report you will learn many interesting facts, all relating to this project. There will be information on fruit, apples and apple trees, sugar, and chromatography.
Fruit
The fruit is the part that contains the seeds of a flowering plant. Each year fruit growers produce millions of tons of fruit. They use three main steps to produce good fruit: planting, caring for the crop, and harvesting the fruit. Fruit trees are perennials, meaning they come back every year and don't need to be replaced each year. Special machinery is used by many fruit growers to help them care for their trees. They use fertilizers to help the trees grow. Pruning usually needs to be done once a year and consists of cutting off all unproductive branches. All fruits are harvested at different times. Most growers use hand picking, but because of the increasing cost, some use machines.
Over time, fruits have been improved by continual selection of the most desirable plants. The plants that are grown from a seed are examined for a certain quality. If that quality appears again when the plant is grown vegetatively it may become a new cultivated variety. Plant breeders use crossing or hybridization to improve fruits. In this technique, breeders take the pollen from one tree and place it in the flower of another tree, both chosen for a certain good quality. Sometimes they are good enough to be named as a new variety.
Horticulturists classify fruits into three groups: temperate, subtropical, and tropical. The temperate fruits include apples, apricots, plums, blueberries, peaches, cherries, and pears. They need to have and annual cold season to grow right. They are mostly grown in North America and Europe. Subtropical fruits need warm temperatures throughout the year, but they can survive a few light frosts. Citrus fruits, including grapefruit, oranges, lemons, and limes pretty much make up the subtropical group. Some others in this group are dates, figs, olives, and avocados. The last group is the tropical fruits. They have to have a warm climate all year round and can't even stand a light frost. Some tropical fruits include bananas, pineapples, coconuts, mangos, and papayas.
The fruit develops from the ovaries of the flowers. It has three layers: exocarp, the outside layer, mesocarp, the middle layer, and endocarp, the inner layer. All together they are called the pericarp. Botanists use this to help them classify fruits another way. They classify them into two different groups: the simple fruits and the compound fruits. The simple fruits come from just one ovary, while the compound fruits some from two or more. The simple fruits are divided into two more groups: the fleshy fruits and the dry fruits. The fleshy fruits have a fleshy pericarp and the dry fruits have a dry one. Some dry simple fruits are the pods of the bean plant, milkweed, pea plant, and locust tree; the grains of corn, rice, wheat; and nuts. Botanist classify nuts as single seeded fruits. The shell as the hard pericarp and the nut as part you eat. The fleshy simple fruits are divided into yet another three groups: berries, drupes, and pomes. A berry's pericarp is completely fleshy. Some berries are bananas, blueberries, grapes, oranges, and watermelons. The berries that have a hard rind, such as watermelons, are called hepos. The ones that have a leathery rind; oranges, lemons, limes, and grapefruit, are called hesperidiums. The fruits that people usually call berries, are not berries at all, most of them are compound fruits. The drupe is a fruit where the exocarp forms a thin skin and the endocarp develops into a stone or pit. Some drupes are cherries, plums, apricots, and peaches. Pomes have a fleshy exocarp with a paper-like core that encloses two or more seeds. Pears and apples are considered pomes. Compound fruits are made of clumps of ripened ovaries. They are also divided into two groups: the multiple and aggregate fruits. The multiple fruits grow from a cluster of flowers on one stem. Some compound multiple fruits are mulberries and pineapples. Aggregate fruits develop from one flower with many ovaries. These would include blackberries and raspberries.
Apples and Apple Trees
The apple tree starts its cycle of growing apples in the winter. It grows buds while it rests in the cold months. In the spring the leaf buds start to swell and break through their protective covering. Curing this same time the flower buds start to grow. They grow at the end of the branches in groups of fives. The bed is enclosed be five sepals, which make up the calyx. The flowers won't open, though, until the tree is completely covered with leaves. Which usually is in the spring.
The flower contains all the materials needed to make new apple seeds. It has five sepals, five petals, a lot of stamen, and one pistil. The stamen produce the male sperm and the pistil produces the t female egg. The sperm is in the pollen that is produced by the anthers. The anthers is the part on the end of the stamen. The egg is made in the ovary, the hollow chamber at the base of the pistil. Inside the ovary is five compartments. In each compartment is two ovules. The ovule contains one egg and all the other materials needed to produce a seed.
The process of fertilization begins with a bee. The bee flies around looking for nectar. The sperm cells in the pollen on the anther, sticks to its hairy legs. When it moves on to the next flower, the pollen sticks to the end of the stigma. Fertilization starts when the pollen splits open, sending the sperm down the stigma, into the ovary. The sperm then gets into the ovary and unites with the egg. As soon as the egg is fertilized, the seed starts to grow. Then the petals fall off and the five sepals pull together to form a tube. Swelling at the base of the ovary occurs, called receptacle. It starts to get round, the calyx, stamens, and pistil will stay with the apple as it grows. In the inside of the apple the parts are starting to grow into the core and flesh of the apple. The ovary is made of several layers. The outside becomes the fleshy white part of the apple and the inner layer becomes the core.
In order to nourish itself, a tree uses photosynthesis. During photosynthesis a tree uses the chlorophyll in its leaves and sunlight to produce glucose. A tree needs 50-60 leaves to nourish just one apple. "June drop" is a time in June when all the apple that aren't getting enough nutrients, fall off the tree. About 85% of the apple is water. When they are mature the apples produce their own food by turning the starch from their flesh into sugar.
Sugar
Sugar is a chemical compound that is soluble in water, has no color, odorless, crystallizable, and usually sweet. Monosaccharides, disaccharides, and trisaccharides are all considered sugar, although Polysaccharides, such as starch, cellulose, and glycogen, are not. Sugar is made in plants during the process of photosynthesis. Glucose, lactose and maltose are used a lot commercially. Sucrose, often called cane sugar, is the most important sugar. Is used to sweeten foods, make candies, cakes, puddings, preserves, and many other foods. It makes up about 13% of the energy we get from food.
Sugarcane is responsible for more than half of the world's sugar supply. It is usually grown in tropical and subtropical climates. Sugar beets make up most of Europe's sugar supply.
Sucrose has the formula C12H22O11. It is often called cane sugar and comes mostly from sugarcane or sugar beets. It is considered a disaccharide.
Glucose is a monosaccharide sugar with the formula C6H12O6. It is less sweet than regular table sugar and is found in fruit juice and honey. Fructose is also a monosaccharide with the formula C12H22O11. It is sometimes called fruit sugar or levulose sugar. It is found in fruits and fruit juices. Maltose has the formula C12H22O11 and is a disaccharide. It is an easily digested sugar so it is often used in infant food. Lactose is the sugar found in milk. It has the formula C12H22O11 and is also a disaccharide. It is not as sweet as sucrose, but is often used in baby food, confections, and pharmaceutical tablets. Sorbitol is only have as sweet as sucrose. It is used in sugar-free candies and products for diabetics. Saccharin is an artificial sugar and is also used in products for diabetics. It is estimated to be 375 times sweeter than sugar. It has been under investigation as a cause of cancer. Recent studies conclude that is does cause cancer in laboratory animals, but does not in humans.
Chromatography
Chromatography is the process of separating and identifying substances that are very similar. It is impossible to do with vitamins, proteins, and hormones. Chromatography was discovered in 1906 by Michael Tswett. He was a Russian botanist who was trying to separate the pigments of plants. It was controlled by observing changes in color. Now it is used for colorless substances, but is still called chromatography. Substances are dissolved into a solvent and then passed over a column of some adsorptive material. Such as activated carbon or synthetic ion exchange resins. Each of the substances are dissolved separately, starting at the beginning. The column is then washed with a solvent and each of the substances are collected.
Summary
As you can see all of this information is connected with my project. This information is here to give you a better understanding of my science project and tell you what I learned. I hope it was interesting to you and you enjoyed reading it.
The original purpose of the experiment was to determine the sugar composition of various brand name apple juices, unknown brand apple juices, and juice blends. Then use that information to calculate the percentage of each kind of juice in the blends and compare the name brand apple juices to the unknown brands of apple juice to see if they are labeled truthfully.
The results of this experiment were that the Apple Raspberry juice was made of 92% apple juice, 5.6% raspberry juice, and 2.4% pear juice. The Apple Grape juice was 63.9% apple juice, 20.8% grape juice, and 15.3% pear juice. The Apple Pear juice was made of 51.7% apple juice and 48.3% pear juice. On the average the unknown brands of apple juice had a higher total sugar content, at 11 g/100 mL, than the brand names of apple juice at 10.52 g/100 mL. For more exact data, see table and graphs on the following pages.
Juice Blend |
Apple |
Pear |
Grape |
Raspberry |
Apple Rasberry |
92% |
2.4% |
5.6% | |
Apple Grape |
63.9% |
15.3% |
20.8% |
|
Apple Pear |
51.7% |
48.3% |
Brand of Juice |
Brix |
Sucrose |
Glucose |
Fructose |
Sorbitol |
Total |
Martinelli's |
14.02 |
1.78 |
3.43 |
8.01 |
0.69 |
13.91 |
Juicy Juice |
11.50 |
1.53 |
2.89 |
5.90 |
0.53 |
10.85 |
Washington's Natural |
12.36 |
2.39 |
2.61 |
6.15 |
0.38 |
11.54 |
Seneca |
11.52 |
1.24 |
3.18 |
6.00 |
0.47 |
10.89 |
Minute Maid |
11.75 |
1.30 |
3.04 |
6.13 |
0.46 |
10.92 |
Tree Top |
11.66 |
0.80 |
3.06 |
6.36 |
0.38 |
10.59 |
Brand of Juice |
Brix |
Sucrose |
Glucose |
Fructose |
Sorbitol |
Total |
Martinelli's |
14.02 |
1.78 |
3.43 |
8.01 |
0.69 |
13.91 |
Juicy Juice |
11.50 |
1.53 |
2.89 |
5.90 |
0.53 |
10.85 |
Washington's Natural |
12.36 |
2.39 |
2.61 |
6.15 |
0.38 |
11.54 |
Seneca |
11.52 |
1.24 |
3.18 |
6.00 |
0.47 |
10.89 |
Minute Maid |
11.75 |
1.30 |
3.04 |
6.13 |
0.46 |
10.92 |
Tree Top |
11.66 |
0.80 |
3.06 |
6.36 |
0.38 |
10.59 |
My hypothesis was that in the studied juice blends, there will be a higher percentage of apple juice compared to the other fruit juices present. Additionally, I hypothesize that all the brands of pure apple juice will be labeled accurately and correctly.
The results indicate that this hypothesis should be accepted because all of the juice blends were in fact mostly made of apple juice. There were two brands of apple juice that had an unusually high amount of sugar, but they also had a different label. They were labeled as "premium" apple juice. I asked a qualified food scientist from the Tree Top Technological Center about this. He said that if a juice is labeled premium it hasn't been turned into a concentrate (it is squeezed and put right into the container). If the juice was turned into a concentrate, water had to have been added to turn it back into a juice. It would then dilute the juice, and the sugars. Therefore, I accept my hypothesis because these juices were not actually mislabeled, but fresh squeezed and not diluted down with water.
Because of the results of this experiment, I wonder if all items on the food market would also be labeled truthfully.
If I were conduct this experiment again I would try to find another way to find the percentages of each kind of fruit juice in the juice blends.
Johnson, Sylvia A., Apple Trees, Minneapolis, Minnesota, Lerner Publishing Company, 1983
"Chromatography," The American Peoples Encyclopedia, 1965
"Chromatography," New Encyclopedia of Science, 1982
"Fructose," Microsoft Encarta Electronic Encyclopedia, 1996
Janick, Jules. "Fruit," World Book Encyclopedia, 1997
"Glucose," Microsoft Encarta Electronic Encyclopedia, 1996
"Lactose," Microsoft Encarta Electronic Encyclopedia, 1996
"Maltose," Microsoft Encarta Electronic Encyclopedia, 1996
RSK Values, Schönborn, Germany, Flüssiges Obst GmbH, 1987
"Sucrose," Microsoft Encarta Electronic Encyclopedia, 1996
Finley, K. Thomas. "Sugar," Academic American Encyclopedia, 1988
"Sugar," Microsoft Encarta Electronic Encyclopedia, 1996
"Sugar Production," Encyclopedia Britannica, 1983
http://www.fda.gov/opacom/laws/fdcact/fdcact3.htm
http://www.fda.gov/opacom/laws/fdcact/fdcact4.htm