Effects of Molasses Concentration on Yeast Fermentation
Effects of Molasses Concentration on Yeast Fermentation The purpose of this lab was to determine how yeast cells are affected by the concentration of a food source, and for our purposes, the food sources were corn syrup and molasses. Our hypothesis was that the yeast cells would ferment the most when there was a higher concentration of molasses/corn syrup. In order to test this, we created 10 test tubes with decreasing concentrations of molasses/corn syrup using a serial dilution. Each test tube then received 10 drops of the yeast solution and was shaken to mix the yeast solution into the molasses/corn syrup mixture. Finally, there was a small test tube added to each larger test tube that would be used to measure the amount of CO2 produced from the fermentation. These tubes sat overnight to allow the process to occur fully. The following day we measured the size of the bubble in the smaller test tube to determine the amount of CO2 that was produced from the reaction.
% Molasses
Height of CO2
Molasses (mm)
Height of CO2 Corn Syrup (mm)
Class Average
Height (mm)
100
0
0
0
50
13
66
40
25
100
55
77.5
12.5
98
50
79
6.25
100
100
100
3.125
100
43
71.5
1.563
27
57
42
.7
17
33
25
.39
6
55
30.5
0
0
0
0
Our group tested the corn syrup, and when we got our results back, we had very few things to observe. The CO2 levels in our test tubes did not change at all at any percentage of molasses.
The independent variable in our lab was the percent of molasses in each test tube. The dependent variable was the height of the CO2 produced from the yeast cells fermenting. The rate of the metabolism of the yeast cells was measured by the height of the CO2 produced- the larger the measurement, the higher the metabolism. The purpose of having a test tube with 0% molasses was to show that yeast cannot have this reaction without any food source. The purpose of having a
% Molasses
Height of CO2
Molasses (mm)
Height of CO2 Corn Syrup (mm)
Class Average
Height (mm)
100
0
0
0
50
13
66
40
25
100
55
77.5
12.5
98
50
79
6.25
100
100
100
3.125
100
43
71.5
1.563
27
57
42
.7
17
33
25
.39
6
55
30.5
0
0
0
0
Our group tested the corn syrup, and when we got our results back, we had very few things to observe. The CO2 levels in our test tubes did not change at all at any percentage of molasses.
The independent variable in our lab was the percent of molasses in each test tube. The dependent variable was the height of the CO2 produced from the yeast cells fermenting. The rate of the metabolism of the yeast cells was measured by the height of the CO2 produced- the larger the measurement, the higher the metabolism. The purpose of having a test tube with 0% molasses was to show that yeast cannot have this reaction without any food source. The purpose of having a
Cited: Lamb, Graham, and George Stephenson. "Point:Counterpoint: Lactic Acid Accumulation is an Advantage/Disadvantage During Muscle Activity." Journal of Applied Physiology. N.p., n.d. Web. 10 Nov. 2013. .