Preservation Techniques for Bananas

Andre Cunningham

City College of New York

Abstract

Bananas are fruits that seem to lose their yellow color very fast when left on a counter. To fix this problem, 3 bananas from the same bunch were examined in 3 different conditions: room temperature, refrigerator and freezer.  This process took over the course of 4 full days with a picture taken each day. The ending results showed that the colder the temperature, the better preserved the banana would be.

 

Introduction

Bananas are fruits enjoyed by many people when yellow but rejected when brown. This happens due to a reaction with an airborne enzyme called ethylene which breaks down acids in the fruit, the main reason for the browning (UCSB ScienceLine). In this experiment, 3 bananas were taken and put in different scenarios: countertop room temperature, refrigerator and freezer. Because the cold usually preserves food and closes out air from outside, the frozen banana experiencing the least amount of browning is expected.

 

Materials

• 3 bananas (from same bunch)
• A refrigerator and freezer
• Camera
• Knife (to open frozen banana on 4th day)

 

Methods

Take 3 bananas from the same bunch and take a picture showing how they look from the beginning. Place 1 in room temperature, preferably a countertop, 1 in the refrigerator and 1 in the freezer. Everyday around the same time when the experiment was started, take a picture of each banana and return it to its original place. On the fourth day, take a picture of both the outside peel and the banana itself out of the peel. To make sure the results are accurate, try to place the bananas in a personal fridge to limit the amount of air coming in and take pictures in a 5 second interval of the banana moving from its spot.

 

Results

On the 4th day, with the bananas out of the peel, the room temperature banana has a huge brown spot on the outside of the arch, the refrigerated banana has spots scattered around and the frozen banana barely shown any heavy browning. The peels of the refrigerated and frozen banana had their skin turn brown while the skin of the room temperature banana kept its original color. Figure 1 shows the bananas at the start of the experiment and figure 4 shows the bananas at the end, in and out of the peel. Both figures, from left to right, shows the room temperature banana, the refrigerated banana and the frozen banana.

 

(Figure 1)

 

(Figure 2)

 

Discussion

As it turned out, my hypothesis was correct. The freezer was proven to be the best way to help a banana from browning. At the beginning of the experiment, all three bananas were very firm going into their 3 different positions. Day 1 of checking in, it was very clear that the banana left in room temperature was already losing its firmness, becoming soft in many spots. As mentioned in the introduction, this is mostly due to the airborne enzyme, ethylene (UCSB ScienceLine). Throughout the rest of the days, the room temperature became browner and softer is more places  (Figure 3).

 

What surprised me the most was the peel of the banana in the freezer quickly turned brown (Figure 5). This was expected because most likely the cold temperature would cause the peel to change colors but it happening in 1 day was very surprising. The theory of the cold temperature working against the peel would come to be true as the browning of the peel became evident in the refrigerated banana in days 3 and 4. The frozen banana was solid as ice throughout the whole experiment. The refrigerated banana was not as hard, but maintained its firmness (Figure 4).

 

The only error that could of have occured during this experiment was taking the bananas out of the original position for 5 seconds in order to take the picture. He air flowing in was sacrificed in order to receive better images of the changing bananas.

 

Day 1              Day 2                  Day 3

(Figure 3)

 

 

Day 1           Day 2              Day 3

(Figure 4)

 

Day 1                Day 2            Day 3

(Figure 5)

 

Conclusion

The purpose of this experiment was to test the best way to preserve a banana. In order to do so we used a room temperature setting, a refrigerator and a freezer. The freezer was proven to be the best way to help a banana from browning. As stated before, the only error that could of have occured during this experiment was taking the bananas out of the original position for 5 seconds in order to take the picture. Everything else was taken care of in order to receive accurate results.

Reference

UCSB ScienceLine, U. (2006, March 01). What causes banana peels to turn brown? California, United States, https://scienceline.ucsb.edu/getkey.php?key=1213