INTRODUCTION

Water is the most essential component of the human body. The human body cannot store water therefore we must always have a fluid intake. There are different recommendations for how much water we should have every day. Some experts recommend the equivalent of 6 to 8 glasses of water a day. When our volume of water decreases in our body we feel thirsty. But we don’t always have to drink our water. Sometimes we can eat it. Many fruits and vegetables have a high amount of water. This experiment will show how much water is in some common foods.

HYPOTHESIS

Some foods look like they have more water than others. We will test some common fruits and vegetables and brown bread. We predict that the fruit and vegetables will have more water than the bread. The fruits we will test are: Banana, apple, and orange. The vegetables tested will be: broccoli (cooked and raw), carrot, (cooked and raw), and tomato. Our hypothesis is that the orange will have the highest amount of water. Next we predict the tomato will have the most water. We predict also that the cooked vegetables will have less water than the raw. We also expect that the lowest water will be in the carrot. The brown bread we expect will have a lot less water than all of the fruits and vegetables.

MATERIALS

Banana, Orange, Apple, Carrot, Broccoli, Tomato, Brown Bread

Sample container, Food processor, Analytical balance, Microwave, Drying oven, Dessicator

PROCEDURE

The apple was cored and sliced up with the skin on. It was blended until well mixed in a small kitchen food processor. The banana was peeled and blended as well. Following blending the sample was put in a sample container. Orange was peeled and chopped up into small portions and placed directly in the sample container. The broccoli was blended raw. A second portion of broccoli was cooked in the microwave. The water was drained off, and the broccoli was blended in the food processor. Similarly, the raw carrots were blended unpeeled, until chopped up very fine. A second amount of unpeeled carrot was cooked in the microwave for 5 minutes then blended. All blended vegetables were put in sample containers. The tomato was chopped in small pieces in the sample container so no water was lost during the chopping. The slice of brown bread including the crust was cut up and put in a sample container. Each sample container was weighed before the food was added. After the food was added each sample container with the food was weighed again. All the sample containers were placed in a drying oven at 97C and left for two days. The sample containers were removed and cooled in a dessicator. The containers were then weighed again.

The water content was calculated the following way:

(Weight of sample before drying) – (weight of sample after drying) x 100 = % water

(Weight of sample before drying)

RESULTS AND DISCUSSION

Besides the air we breathe, the next most important thing for life is water. Water is used by our bodies in every chemical process that goes on inside of us, such as digestion, and circulation. Usually we maintain just the right amount of water in our body. When we need water we know it because we get thirsty. However thirst sometimes doesn’t start quickly enough . On a hot summer day we can become dehydrated. We can afford to lose some of our fat and carbohydrate stores, but a loss of only 5% of our bodies water can result in heat exhaustion. A loss in 10% can lead to heat stroke and collapse. Water is replaced in our bodies in two ways; our bodies make water, or we can eat or drink water.

In our experiment we found many fruits and vegetables are full of water. We tested three different fruit, apples, bananas, and oranges. We also tested some vegetables, tomato, broccoli and carrot. We also cooked some broccoli and carrot nd tested the cooked vegetables for water content. For comparison purposes we tested a slice of brown bread. The results are found in Table 1.

TABLE 1

CONTAINER #	WT OF CONTAINER	WT OF CONTAINER +FOOD	WT OF CONTAINER + FOOD AFTER DRYING	DIFFERENCE	PERCENTAGE OF WATER
#1 (BANANA)	2.2738	61.092	15.8499	45.2421	74.1%

#2 (APPLE)	2.2670	49.7329	6.8508	42.8821	86.2%

#3 (BROWN BREAD)	2.2614	17.1342	11.1795	5.9547	34.2%

#4 (ORANGE)	2.2833	81.298	12.2952	69.0028	84.9%

#5 (BROCCOLI) raw	2.2836	30.2277	4.7393	25.4877	85.6%

#6 (TOMATO)	2.2839	40.0014	4.6686	35.328	88.3%

#7 (CARROT) raw	2.2616	38.4625	5.7404	32.7221	85.1%

#8 (CARROT) cooked	2.2854	39.3962	7.6992	31.697	80.5%

#9 (BROCCOLI) cooked	2.2784	39.1652	5.6270	33.5382	84.3%

Of the fruit we tested, we found the highest amount of water was in the apple. This was a little surprising since oranges appear to have more water. They were close in water content, the apple had 86.2% water and the orange had 84.9% water. The banana had the least amount of water of the fruit at 74.1% water, although this is still a lot of water. Of the raw vegetables tested the tomato was the highest in water, 88.3%. This was the highest of everything tested. The raw broccoli was also very high in water at 85.6% water followed by the raw carrot with 85.1% water. Both vegetables lost water with cooking; the cooked carrot lost 5% of its water, with 80.5% water in the cooked carrot. The broccoli also lost water after cooking, with 84.3% compared to 85.6% a loss of 1.3%. This loss in water is caused by heat, which causes the cell walls of the plant to break down, letting some of the water leak out. The bread had the least amount of water, which we expected, with only 34.2% water.

CONCLUSIONS

We need water to live. We can get water in many ways. The most obvious way is to drink liquids. However, we can also get a lot of water from eating vegetables and fruits. The best way to eat your vegetables, if you need water is to eat them raw. So remember the next time you are thirsty, drink a banana!

Bibliography

1. Moisture content in foods: Chemical Methods Manual, Canadian Food Inspection Agency, Government of Canada 1999.

2. 10 Flavorful Ways to Get your Daily Water www.ediets.com/news

3. Determining Moisture Content in Foods www.foodtechsource.com/rcenter/

4. Food Analysis www.helios.bto.ed.ac.uk/

5. More than One in Three Older Americans May Not Drink Enough Water Nutrition Insights, USDA Center for Nutrition Policy and Promotion, September 2002.

6. Water Content www.foodreference.com/

With thanks to Joe Pickett of the Canadian Food Inspection Agency who helped us with this project.

THIRSTY? DRINK A BANANA!

Project Summary

1. How did we come up with our project idea?

One day while we were eating cut up apples about if inside fruit was full water or had barely any water at all. We thought then that that would be a good experiment idea.!!!

2. What did we learn from our experiment?

Even though a fruit or vegetable looks bigger it doesn’t mean that it has more water content for ex: an orange looks bigger but a tomato actually ha more water content!!!

3. How close were our hypothesis and conclusion?

Well our hypothesis was that the orange would have the most water because it was the heaviest and the largest but we were wrong. Our conclusion was the tomato had the most water content then all the fruits and vegetables that we tested.

4. Did we learn anything new from our project?

We learned that everyday foods have a lot of water. We also learned that water is an essential part for life. We need water to live and grow.

5. What was the most interesting part of our project?

The most interesting part of our project was going to a lab to test the water content in food. We used the same method to test food as a real scientist would. We learned a lot of interesting facts and also learned that we can DRINK BANANAS!!!!!

Karen and Erinn

Grade 5

St. Bonaventure's College

St. John's N.L.

More Info

Nutrition