the effect of different levels of ph on the fermentation of yeast
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The Effect of Different Levels of pH on the Fermentation of Yeast. By Rachel Koch. Hypothesis and Problem Statement. Problem: How do different levels of pH in the environment around yeast effect its fermentation ? Hypothesis: - PowerPoint PPT PresentationTRANSCRIPT
The Effect of Different Levels of pH on the Fermentation of Yeast
By Rachel Koch
Hypothesis and Problem StatementProblem: How do different levels of pH in the environment around yeast effect its fermentation?Hypothesis:If the environment around the yeast has a higher pH, then the yeast will create more CO2.
Background Research Yeast: microorganism, Eukaryotic
domain and the Fungi kingdom
Baker’s yeast: digests sugar
Fermentation: release carbon dioxide
Energy and warmth for fermentation
Dough rising is result of fermentation
Design Diagram
Levels pH of 5 pH of 6 pH of 7(control)
pH of 8
Trials 5 5 5 5
Title: The Effect of Different Levels of PH on the Fermentation of Yeast
Hypothesis: If the environment around the yeast has a higher pH, then the yeast will create more CO2.
Design Diagram cont.IV: pH levelDV: Height of dough(cm)Constants: Ingredients in dough
(besides IV), the measurements of each ingredient, temperature at which the dough is placed to ferment and the amount of time the yeast ferments.
MaterialsFlourSugarInstant yeastWarm water/solutionOilSaltRulerHClNaOHOven
Procedure• Prepare pH solutions in lab with the instructor using NaOH for basic solutions and HCl for acidic solutions.
1. Heat water/solution to 35 degrees C.
2. Add flour, sugar, oil, yeast and salt to the warmed water/solution.
Procedure cont.3. Knead dough for about 8 minutes.
4. Measure the height of the dough.
5. Store dough in a warm place for 45 minutes to allow yeast to ferment.
Procedure cont. 2 Put dough in the oven set to
54 degrees C and turn the oven off
6. Measure the final height that the dough raises with a ruler.
Photodocumentation
Data
pH 5 pH 6 pH 7 (control)
pH 8
Trial 1 4.5 cm 2 cm 4.5 cm 3.5 cmTrial 2 5 cm 3 cm 4 cm 3 cmTrial 3 5 cm 3 cm 4 cm 3.5 cmTrial 4 5 cm 3.5 cm 4.5 cm 3 cmTrial 5 4.5 cm 2.5 cm 4 cm 3 cm
Averages 4.8 cm 2.8 cm 4.2 cm 3.2 cm
AveragesPH 5: 4.8 cmPH 6: 2.8 cmPH 7 (control): 4.2 cmPH 8: 3.2 cm
Graph
pH 5 pH 6 pH 7 pH 80
1
2
3
4
5
6
Level of pH
Hei
ght
of d
ough
in
cm.
The Effect of Different Levels of pH on the Fermentation of
Yeast
Statistical Analysis
Source of Variation
Sum of squares
Degrees of Freedom
Mean Squares
F Significance
Between 13.14 3 4.379 33.37 0.000
Error 2.1 16 0.1313
Total 15.24 19
ANOVA
ConclusionsHypothesis did not support dataIdeal environment is pH 4-6Yeast ferments better in acidic
substancesData is inaccurate
Possible ErrorsOven temp. wasn’t exactly the
same every timeMeasurements might not have
been exactMeasured every half centimeter
ImprovementsCould buy an alternative heating
deviseMeasure ingredients more
carefullyMeasure the height to a tenth of
a cm
ReasoningLike to bake
Thought it was interesting that yeast makes dough rise
ExtensionsTest other factors that effect
yeast fermentation, like:oTemperatureoAmount of sugar
Acknowledgements Mrs. Po Preparing solutionso Helping
Parentso Bought ingredients
Bibliography"Basic Bread." PrismNet : Austin TX VOIP, Broadband Colocation, Web Hosting. Web. 05 Oct.
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<http://herbarium.usu.edu/fungi/funfacts/Fermentation.htm>.
"What Are Yeasts?" Saccharomyces Genome Database. Web. 05 Oct. 2010.
<http://www.yeastgenome.org/VL-what_are_yeast.html>.
Campbell, Neil A., Jane B. Reece, Lawrence G. Mitchell, and Martha R. Taylor. Biology
Concepts & Connections. San Francisco: Benjamin Cummings, 2003. Print.
"Factors Effecting Fermentation." Web. 19 Dec. 2010.
<http://home.earthlink.net/~ggda/factors_effecting_fermentation.htm>.
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<http://www.dakotayeast.com/help-fermentation.html>.