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LAB REPORT : DEHYDRATION OF FRUIT �1

Food ScienceDehydration of Fruit to Determine Moisture Content

Pear, Gam, Jaja and Tientien 1005 Jan, 14 and 15 2016

Introduction As we know, our body is composed of large amounts of water. We can get those water from metabolism, drinking and eating food. Every food that we eat contains water. Some contains a small amount of water, while some contains a lot amount of water. There are three different types of water in food. First one is bulk or free water. Bulk water is the water molecule is surrounded by water molecules. Water in this type can easily be removed such as squeezing. The second type is trapped or capillary water. This type of water is hard to remove because it is trapped by physical barriers. It’s held in a small tube The last one is bounded water. This type of water is the water that contact with the food constituents, but it can also bond with the water molecule. These bonds are stronger and harder to remove. If we talk about the food that contains a lot of water, one type of food that contains a large amount of water is fruit. How do we know how much water is inside the fruit? We can use one process which is called dehydration.

Dehydration is one of the easiest ways to preserve food from turning bad. It is a process of removing the water or moisture from the food by evaporation which makes fruit becomes drier. By removing water in the food, we also remove some organism out too because they need water in order to stay alive. This process makes us prevent spoilage in food. There are many ways to dehydrate food such as sunlight, oven or dehydrator. Dehydrator is the fastest and the most efficient way because we can control the temperature.

When we do dehydration. The fruit lose some weight. The thing that it lost is water. That is called moisture content which is the amount of water per unit mass of moist. We can calculate by finding the difference of weight between the mass of food before dehydrate, and the mass of food after dehydrate, then divides the difference by the weight of water before dehydration. After that multiply by one hundred to make it become percentage.

In this experiment, the fruit that our group choose and prepare is pineapple. Another groups choose orange, strawberry, apple and banana. Our purpose is to learn how dehydration works and we want to see how different of moisture content in each type of fruit.


Materials

Pineapple Knife Wax paper Electronic balance

Ruler Pen Dehydrator


1. Obtain the pineapple. 2. Each member cut the pineapple in the equal size. One piece per each person. 3. Observe the pineapple, draw a picture of it and measure the size of it including the thickness 4. Cut a wax paper to fit the slide and mass it by using the electronic balance. Then re-zero and mass pineapple. After that mass the pineapple with the wax paper. 5. Record the mass in the data table. 6. Place the pineapple on a rack of the dehydrator. Make sure that it is spaced evenly apart. Then leave for 24 hours.

Procedure

Part 1

1. Next day, obtain pineapple from the dehydrator. 2. Each member mass their own pineapple in grams. Do the same as part 1 which are massing wax paper first, re-zero, massing the pineapple and mass both of them together. 3. Record the mass in the data table. 4. Draw a picture of the dehydrated sample, and measure the size of it. Describe its characteristics compared to the original sample.

Part 2


Data table

TienTien’s pineapple

Average = 84.79%

pineapple- silky


Jaja’s pineapple

pineapple

Pear’s pineapple


These are our pineapples after dehydration

Gam’s pineapple


Discussion

1. Why did the weight of the sample decrease? Explain. Dehydration is a process that removes water or moisture from food by evaporation. The weight of a pineapple decrease because water in pineapple is highly evaporated when the temperature in dehydrator reach at the boiling point of water, water will evaporate into a gas. When the water come out, pineapple will become drier and it also lost the weight because of losing water.

2. Each group member should comment on the changes they observed from the wet to dry sample. We observe pineapple before dehydrate and after dehydrate pineapple such as size,colour and smell Gam: Before we dehydrated the fruit sample that we chose, pineapple was really juicy and watery. Its smell’s sour. Its colour’s pale yellow. Its taste’s sweet like a general pineapple and it’s thick and soft. After dehydrating, pineapple became thinner, drier and stickier. Its smell like a chip. Its taste’s sweeter, sourer and also saltier than the original one. When we ate it, it’s very hard to chew. Its size’s smaller than the one that not dehydrate. And also its mass decreased because it lost a lot of water. But I think that it’s not completely dehydrated because it still wet and it might need more time to dehydrate it.

Tientien: Before we dehydrate pineapple. It’s very watery and has a smell that’s very good like normal pineapple. It has the colour that bright and the taste is very sweet. It’s very soft. The size of its is thick. But after we dehydrate pineapple by dehydrator remove all of water in pineapple out. It becomes more yellow, drier and sticky. It has the smell that likes chips. The taste is a little bit salty but when we chew longer it’s more sour. And the size of its is smaller than before dehydrated. The colour of its is more yellow. But we observe that it still a little bit wet and think it need more time to dehydrate to make it drier. Jaja: Before we did an the dehydration step, the pineapple’s watery and soft. It had a bright yellow color and had a bit smell. When we cut it, water moved out from the pineapple all time because it’s very moist. It had a soft structure like a jelly in sheet form. After the dehydration step, it changed to harder and dry but not completely just have a bit damp. The shape of it changed to twisted shape and smaller because it shrink. The pineapple still had a smell but more than before, we thought that its smell like a chips and a bit sour. It become more sticky and more yellow. After we ate, taste of it is very sour and sweet with a bit salty.


Pear: Before the fruit dehydrated, pineapple was moist.The color is pale yellow and smelled a bit of sour. The texture of it is both soft and hard. It is soft that we can press it, but it is hard enough to make it not lose its proper shape when we press. After the fruit dehydrated, pineapple becomes sticky. It feels like it is drier and harder, but it is still a bit wet. The color of it becomes more yellowish and the smell of its is like potato chips and stronger than before dehydrating. The taste of it is a bit salty and very sour. It is very sticky that we it is hard to bite and chew. The size and the mass of it is also a lot smaller.

3. Do you think your sample needed more time to dry? Why or why not? Our sample which is pineapple is almost dry, but we think that it is needed more time to dry because after we dehydrated pineapples and observe them, we think that they are still a little bit wet, so if we have more time, it might become drier.

4. How did the average moisture content of the other fruit samples compare to your group? Pineapple have average moisture content at 84.79%. Apples have 82.77%. Strawberries have 88.56%. Oranges have 82.25%. The last one which is banana have 72.74%. From the experiment, we knew that strawberry is the fruit that contain the most moisture content (88.56%) and banana is the fruit which contain the least moisture content (72.74%) in this class. Therefore, our sample which is pineapple contain a lot of water at the second in the class.

5. Why did some samples dehydrate more efficiently than others? (For within your group and also between different groups) There are many things that affect how fruits dehydrate. First is the size. Even though entire pineapple has the same moisture content, but the cutting pieces of our group member can be different due to the size of them. Tientien’s fruit sample was the most efficient in size compared to other group’s member because she had the smallest size and mass. The second thing is the place where we put in the dehydrator. In this experiment, Gam had the most efficient in this case. Even though she had almost largest size samples, but after dehydration process Gam samples almost had the same moisture content as Tientien. Gam place her samples near the center of dehydrator, so the place where we put in the sample is important to influence the result. The last but not least is the type of fruit. Different fruit has different moisture contents. If you look into average of moisture of each group that has different fruit, you can see that strawberry is the fruit which contain the most moisture content which is about 88.56% and banana is the fruit which contain the least moisture content 72.74% in this class. Therefore the types of fruit affect the efficiency of fruit dehydration.


6. Research advantages and disadvantages to dehydrated food products and explain. Advantages of dehydrated food are changing the taste or improve the fruit’s taste. When water moves out, food is more sugary treats, but it depends on personal sensory too. Some dried food can also add flavor to improve boring foods. They are lightweight so they can be moved very easily. The foods that already dehydrate can weigh as 10% of fresh food before the dehydration process. Another advantage is that they can be kept longer than fresh food so it’s very easy to save them if you bought them too much. On the other hand, dried food does not have taste same as fresh food, someone might prefer fresh foods than dried foods. They might have some mold on food. Dried foods are high in fiber, but too much for you. They might cause you to have gas, bloating, possibly diarrhea, abdominal cramping or constipation. They are too dry so they often do not soften.

Bibliography

Anne, M. (n.d.). The Disadvantages of Dried Fruit. Retrieved from sfgate: http://healthyeating.sfgate.com/disadvantages-dried-fruit-3227.html Brown, D. (2015, February 10). The Advantages and Disadvantages Part II. Retrieved from Hubpages: http://hubpages.com/food/homepreservationadvantagesanddisadvantagespt2 Food Dehydration. (n.d.). Retrieved from Monroeps public schools: https://sites.google.com/a/monroeps.net/dehydrationsag/

Conclusion

From the experiment, we have learnt that dehydration makes the fruit change in texture, colour, flavor and weight. Dehydration has both advantages and disadvantages, so we have to consider which way is most appropriate for our products. The result of the moisture content in our fruit is 84.79%. It shows us that the fruit has a lot amount of water. And the different kinds of fruit have the different moisture content depends on the amount of water in each kind of fruit.


Work log

Pear - Introduction, Q#2,5 and conclusion Gam - Introduction, Q#2,4 and conclusion JaJa - Material, procedure, Q #2,6 and conclusion Tientien - Data table, discussion Q. #1-3 and conclusion

Documents

Lab report dehydration - Weebly