The Effect of Liquid Preservatives on Strawberry Decay

Student: Lucy Melchior
Table: 10
Experimentation location: Home
Regulated Research (Form 1c): No
Project continuation (Form 7): No

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The purpose of this experiment was to determine the best liquid preservative to help preserve strawberries for a span of two weeks. The prediction was that if honey, aloe vera, and white vinegar were used to preserve strawberries, then the honey will produce the least amount of decay. During this experiment, the constants were the number of strawberries on each plate, the amount of time the strawberries were monitored, how long the strawberries were dunked in their assigned preservatives, and the same sized cups were used for each liquid preservative. The independent variables were the different liquid preservatives and the dependent variable was the amount of strawberry decay per strawberry. The amount of strawberry decay was measured by how many had decayed in total per plate. If a strawberry had dark brown spots or an odor, it was considered decayed. After 14 days, the results showed that the White Vinegar strawberries produced the least amount of decay with only 5 decayed. All of the other strawberry levels had all 6 decayed by the end of two weeks. Because of these results, the hypothesis is rejected. This is due to the fact that the hypothesis predicted that the honey would produce the best results, but after completing the experiment, the results showed that the white vinegar did the best. If I redid this experiment I would use a more dedicated refrigerator to make sure the temperature stays steady throughout the entire experiment. This would keep the results more fair.


Works Cited:

“Aloe Vera Coating May Prolong Freshness, Safety Of Fruits And Vegetables.” ScienceDaily, Accessed 15 Oct. 2020.

Farrelly, Lauren. “How Does Mold Grow on Food?” Sciencing, Accessed 17 Oct. 2020.

Hill, Ansley. “White Vinegar: Ingredients, Uses and Benefits.” Healthline, Healthline Media, 31 July 2018,

“How Long Do Strawberries Last?” Still Tasty, Accessed 17 Oct. 2020.

Mandal, Manisha Deb, and Shyamapada Mandal. “Honey: Its Medicinal Property and Antibacterial Activity.” Asian Pacific Journal of Tropical Biomedicine, vol. 1, no. 2, Apr. 2011, pp. 154–60. PubMed Central, doi:10.1016/S2221-1691(11)60016-6.






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Research Plan:

The title of this project is The Effect of Different Liquid Preservatives on Strawberry Decay. The question asked for this experiment is: What is the best liquid preservative to help preserve strawberries for a span of two weeks? The hypothesis is, If honey, aloe vera, and white vinegar are used to preserve strawberries, then the honey will produce the least amount of decay. 


The materials needed to hold the preservatives and strawberries are six ceramic plates and five plastic cups of any size (all should be the same size). The preservatives needed are Honey 12 oz (available from online stores), Aloe Vera Juice 32 fl oz (available from online stores), White Vinegar 64 fl oz (available from online stores), Aloe Vera Gel 4 fl oz (available from online stores), and Water. Two tubs of 1-gallon strawberries are also required for this experiment, along with one dispenser of plastic wrap. Some other materials needed are sticky notes and sharpies for labeling. 


To begin this project, lay six ceramic plates across the workspace next to each other. The second step of this procedure is to label six sticky notes: (Honey, Aloe Vera Juice, Aloe Vera Gel, White Vinegar, Water, Zero Treatment) with a sharpie marker, and assign one to each of the plates. Next, measure and pour half of a cup of each liquid preservative into each cup and place them behind each plate. Using a pH strip, carefully test the acidity of each liquid preservative and record it on a data table. Grab the strawberries out of the refrigerator and place the cartons on the workspace. Lay six strawberries on each plate and then dunk each of them in the preservative behind their assigned plate for seven seconds. Once this is complete, lay them back on their plate and cover the plates in plastic wrap. After wrapping the plates in plastic wrap, place them in the refrigerator for two weeks. Remember to check on them each day and calculate the number of strawberries from each plate that have decayed. 

Risk Analysis

There are no extreme risks involved with this experiment, but when dealing with ceramic plates, make sure to handle them with care because they can break easily if dropped or handled carelessly. 

Data Analysis:

During the 14 days of this experiment, the number of strawberries decayed each day is calculated on two graphs. The first graph depicts days 1-7 (the first week) and the pH levels of each liquid preservative. The second data table depicts days 8-14 when most of the change is expected to occur. After this data is collected, a line graph will be made with six lines for each liquid preservative. To tell each line apart on the graph, a key will be created and the lines will be color-coded, and the graph will be from days 8-14. This is due to the fact that most of the change will occur during this time because strawberries are not long-lasting berries.

Questions and Answers

1. What was the major objective of your project and what was your plan to achieve it? 

The major objective of this project was to determine the best liquid preservative to help preserve strawberries for a span of two weeks. To achieve this goal, extensive amounts of research were done, a hypothesis was created, a list of materials was created, a procedure was developed, and data was collected. To ensure this project would be useful, there were research questions answered such as, "White is white vinegar?", "How can honey prevent mold growth?", "What is the purpose of Aloe Vera Juice", "What is mold and why does it occur," and "How long does it normally take for strawberries to grow mold?" After answering these questions during research, a hypothesis was developed to make an educated guess on what liquid preservative would preserve strawberries the best. After this, a list of materials was made of the liquid preservatives, strawberries, and other materials needed for this experiment. Once the materials were fully discussed and a list was created, the procedure was made which involved testing the pH levels of each preservative, dunking the strawberries for 7 seconds, and placing the strawberries in the refrigerator for 14 days. During these 14 days, data was collected on a table and the results were analyzed and made into a graph.

       a. Was that goal the result of any specific situation, experience, or problem you encountered?  

To make this procedure perfect and the best it could be, more research was done to ensure the first draft of it would work. Originally, the strawberries were to be left on the counter for a span of two weeks and would not be covered with plastic wrap. After realizing the flaws in this idea, another draft of the procedure was made. If the strawberries were not covered and were left on the counter, bugs such as ants would be drawn to the sweet smell of honey and aloe vera. Without the covering of plastic wrap, this would cause the ants to be able to enter the strawberries and ruin the experiment. Another reason this idea was scratched was because of the fact that strawberries are normally kept in the refrigerator on normal terms. If they were not kept in there during the experiment, they would not be in their correct environment or rot more easily. To make this experiment more realistic and fair, they were placed in a drawer of the refrigerator for two weeks. That seemed to work perfectly. 

       b. Were you trying to solve a problem, answer a question, or test a hypothesis?

For this particular experiment, a question was supposed to be answered. The question was, "What is the best liquid preservative that can help preserve strawberries for a span of two weeks?". To answer this question, honey, Aloe vera, water, and white vinegar were tested to see how well they could preserve the strawberries. Though a hypothesis was created, it was used as an educated guess on which of the preservatives I thought would make the strawberries produce the least amount of decay. The question during this experiment was answered and acknowledged, as well as being answered in the conclusion. 

2. What were the major tasks you had to perform in order to complete your project?

To complete this experiment, extensive amounts of research had to be done in order to create a hypothesis and develop a plan/procedure. The research took about a week and many questions were asked to create a great idea of what the best known liquid preservatives were. Another major task that needed to be completed was ensuring the strawberries were kept at a steady temperature during this experiment. To do this, they were kept in the same drawer so that opening and closing the refrigerator would not affect the strawberries as much. The reason this became a problem is due to the fact that the refrigerator used during this experiment was the main fridge in the house, meaning everyone in the household uses it. The door opening and closing causes the temperature to fluctuate, which is why they would be at risk of changing temperature. While being kept in the drawer, they were safer and this was another task that was done during this experiment. Other than these, the experiment was mostly steady flowing!

       a. For teams, describe what each member worked on.

The entire experiment was created and developed by myself.

3. What is new or novel about your project?

While doing research, I learned of Aloe Vera Juice and its benefits on fresh fruits in stores. In most grocery stores, aloe vera substances are used as a coating to preserve certain fresh fruits so that they stay shiny and healthy in the stores. This draws the consumers into the fruits and makes them look better on-shelf. After learning about this in research, I questioned the differences between aloe vera juice and gel. I hadn't seen any tests of the gel used before on fruits, but I wondered if the reason aloe vera juice is used is because of its juicing ingredients or its aloe vera. From there, I added Aloe Vera Gel to my materials list and begun the experiment. I am not entirely sure that no one has tested Aloe Vera Gel before, but it is something new that I learned. The results confirmed that Aloe Vera Gel is not a great preservative, but the juice held out for a longer period of time.

       a. Is there some aspect of your project's objective, or how you achieved it that you haven't done before?

The point of this experiment was to determine the best liquid preservative to help preserve strawberries for a span of two weeks. Before doing research and conducting the experiment, I had never tried preserving fruit after purchasing it from the store. However, I have heard of the preservation of food in grocery stores, as well as homemade preservatives for eggs and milk. Other than this, I had never done this sort of thing myself or with parental supervision, but after completing this experiment, I will use the results in the future for my own sake.

       b. Is your project's objective or the way you implemented it, different from anything you have seen?

During my experiment, the strawberries were dunked in their assigned liquid for seven seconds. It was imperative that they were dunked for this long so that the liquid would fully sink into the strawberries and possibly cause a full effect. They were also dunked for this long so that they were fully covered and the results would be fair for each strawberry. In grocery stores, fruits are preserved too with Aloe Vera juice. However, these fruits get a light coating of preservatives to make them shiny while still on the shelf in an aisle. Though there is a difference between the experiment and the reality, the results are still promising in both.

       c. If you believe your work to be unique in some way, what research have you done to confirm that it is?

I do not believe that my project is unique, however, the aloe vera gel used in the experiment had never been used in the research that I did. Aloe Vera gel is used to relieve sunburn and any kind of burn of the skin. It is not proven to help with preserving foods, but I tested it anyway. The main reason aloe vera juice and gel were tested was so that I could see the difference between formulas and how they affect the strawberries. This was not the entire reason the experiment was created, but it was one of the reasons aloe vera was tested. Other than testing aloe vera gel, there is nothing else too unique about this experiment.

4. What was the most challenging part of completing your project?

The most challenging part of completing this project was checking the strawberries at the same time each day. It was crucial that the strawberries had a full 24 hours to continue their decaying cycle due to the fact that the strawberries are observed daily. If they do not have the full 24 hours, the results would not be fair and they wouldn't truly be checked daily. To ensure the strawberries were checked at the same time, they were checked right at noon (12 pm) and a timer was set. This however was difficult because other daily activities and events could have gotten in the way of this experiment as well as forgetting to set the timer. It was imperative not to forget this step, and I made sure this did not happen. Overall, this problem was solved, but that was the most challenging part. 

      a. What problems did you encounter, and how did you overcome them?

One problem that occurred during this experiment was having to revise the procedure. This was because originally, the strawberries were to be kept at room temperature and have no tinfoil. After doing some research and studying the best climates for strawberries and how mold grows, I learned that they need to be in cold climates, and mold grows in damp, warm places. To prevent this from happening, the strawberries were covered in plastic wrap (to prevent bugs from ruining the experiment) and placed in the refrigerator. Another problem that occurred was testing the pH levels of the liquid preservatives. For this, oH strips were used that are quickly dipped into the preservatives and then change color depending on the acidity. Sometimes, pH strips are not accurate depending on how long they are dipped into the liquid and if more than just the tip of the strip is placed in the liquid. This caused a problem and the accuracy could have been off on the data table. Other than these slight problems, the experiment went smoothly!

      b. What did you learn from overcoming these problems?

I learned to always trust the research because it can make the experiment more realistic and useful. If you do not trust the research, it can lead to a flawed experiment or unfair results.

5. If you were going to do this project again, are there any things you would you do differently the next time?

If I were to complete this project again, I would make sure to have a dedicated refrigerator to ensure the strawberries are kept at a steady temperature and the results are fair. During the experiment, they were kept in a drawer to make sure the temperature of the refrigerator did not affect the strawberry's conditions. Another thing I would do differently is purchasing a pH meter. During this experiment, the pH levels of each liquid preservative were tested and recorded on a data table. PH strips were used which are less accurate than pH meters. A pH meter would give better results because the human eye can perceive the color of the pH strips, which would not cause accurate results.

6. Did working on this project give you any ideas for other projects? 

After drawing a conclusion that the White vinegar had the best results with only 5 decayed after 2 weeks, I wondered if other kinds of vinegar would work as a preservative. White vinegar goes through a fermentation process which draws the excess water and carbon dioxide out of the strawberries to help preservatives. Other kinds of vinegar go through the same process but aren't normally using for preserving. To test this experiment further, I would try testing the strawberries with different kinds of vinegar such as wine vinegar, apple vinegar, and rice vinegar.

7. How did COVID-19 affect the completion of your project?

COVID-19 did not have any negative on my project. However, it helped me stay home and monitor my strawberries for a longer period of time so I could take pictures and make sure I observe them at the same time every day.