Transcript Going Bananas: The Effect of Temperature on the Ripening of

Going Bananas:
The Effect of Temperature on the
Ripening of Bananas
Tracey Merz
Grade 10
http://www.freeclipartpictures.com/pictures/banana.jpg
Question
Does temperature have an effect
on the rate of ripening of
bananas?
Background Information
 A refractometer is a device that measures the
speed of light in a substance.
 Ripening in fruit is controlled by the plant
hormone ethylene. Ethylene increases the
levels of certain enzymes in fruit, including
amylase, pectinase, and chlorophyll.
 At low temperatures, enzymes have low
kinetic energy.
 As temperature increases, the enzymes gain
energy.
Refractometer
http://www.yourgemologist.com/Refractometer/refractometer1.jpeg
Hypothesis
If bananas are stored at 10, 20, or 30
degrees Celsius, then those stored at 30
degrees Celsius will ripen the most
quickly, while bananas stored 20 degrees
Celsius will ripen at a slower rate and
those stored at 10 degrees Celsius will
ripen the slowest.
Materials











Fifteen bananas
Metal dinner fork and knife
Three dinner plates
Cheesecloth
Scissors
Three opaque containers
Dextrose
Water
A refractometer
A refrigerator
An incubator
Procedure
 The control was made by placing a few drops of the
0% dextrose-water solution on the lens of the
refractometer to find the degrees Brix, and then
doing the same with the 10%, 20%, 30%, and 40%
solutions.
 5 bananas were placed at 10 degrees, 5 bananas at
22 degrees, and 5 bananas at 30 degrees Celsius.
 A banana kept at 10 degrees Celsius was cut,
mashed, and placed on cheesecloth. A few drops of
juice was then squeezed onto the lens of a
refractometer.
 One banana was used at each temperature for five
consecutive days.
Variables
 Independent: The temperature at which the
bananas were stored
 Dependent: The rate at which the fruit
ripened
 Control: Dextrose-water solutions of 0%,
10%, 20%, 30%, and 40% sugar
 Constants: The amount of time in the
experiment, the type of bananas, where and
when the bananas were purchased, the
refractometer, the amount and type of
cheesecloth, the scissors, the fork and knife
used, the plates, the type of containers in
which the bananas are stored, the type of
sugar in the control
Degrees Brix
Average Results By Temperature: 10 degrees
Celsius
30
28
26
24
22
20
18
16
Percent Sugar
1
2
3
Day
4
5
Degrees Brix
Average Results By Temperature: 22 degrees
Celsius
30
28
26
24
22
20
18
16
1
2
3
Days
4
5
Percent Sugar
Average Results By T emperature:
30 degrees Celsius
30
Degrees Brix
28
26
24
Percent Sugar
22
20
18
16
1
2
3
Day
4
5
Results From ANOVA Testing
Day
P-value
1
0.002535687
2
2.740910E-05
3
3.016280E-06
4
6.400000E-05
5
2.940120E-05
The P-value for each day was well below 0.05.
Conclusion
 The hypothesis was supported. Bananas stored
at 30 degrees exhibited ripening after one day,
those at 22 degrees ripened after four days, and
those at 10 degrees showed no significant
ripening.
 The p-values were well below 0.05, showing the
data found is repeatable and statistically
significant.
 The bananas ripened at an average of 0.978
degrees Brix per day. This formula could be
used to find the Brix on other days or
temperatures.
Conclusion, Continued
 A possible source of error was that
experimentation was performed at various times
of the day, so the time period that the bananas
ripened each day was different.
 Further experimentation could include using a
prolonged period of time and other
temperatures.
 In a practical application, consumers and
vendors wishing to expedite the ripening
process of bananas can stow them in a warm
location.
Works Cited
 Antony, W., Staley, D., Matta, M., & Waterman, E. (2008). Amino
acids and their polymers. In Chemistry (pp. 769-773). Boston,
Massachusetts: Pearson Prentice Hall.
 Batt, C. (1999, September 29). Glucose sweetens fruit as it ripends.
Retrieved October 15, 2010, from Cornell Center for Materials
Research website:
http://www.ccmr.cornell.edu/education//.html?quid=205
 Biology Online. (2005, August). Growth and plant hormones.
Retrieved October 19, 2010, from Biology Online website:
http://www.biology-online.org//10_growth_and_plant_hormones.htm
 Daintith, J., & Rennie, R. (2010). Refractometer. Retrieved October
15, 2010, from Facts On File, Inc. database.
 Hopkins, W. (n.d.). Flowers and fruits. Retrieved October 6, 2010,
from Facts On File, Inc. database.
 Kendrick, M. (2009, August 17). The origin of fruit ripening. Retrieved
from Scientific American website:
http://www.scientificamerican.com/.cfm?id=origin-of-fruit-ripening
 Mueller, S., & Vasquez, S. (2009). Refractometer calibration, use, and
maintenance [Article]. Retrieved from University of California
Cooperative Extension website: http://cefresno.ucdavis.edu//.pdf