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
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The Effect of Different Levels of pH on the Fermentation of Yeast
By Rachel Koch
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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.
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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
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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.
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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.
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MaterialsFlourSugarInstant yeastWarm water/solutionOilSaltRulerHClNaOHOven
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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.
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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.
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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.
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Photodocumentation
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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
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AveragesPH 5: 4.8 cmPH 6: 2.8 cmPH 7 (control): 4.2 cmPH 8: 3.2 cm
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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
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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
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ConclusionsHypothesis did not support dataIdeal environment is pH 4-6Yeast ferments better in acidic
substancesData is inaccurate
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Possible ErrorsOven temp. wasn’t exactly the
same every timeMeasurements might not have
been exactMeasured every half centimeter
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ImprovementsCould buy an alternative heating
deviseMeasure ingredients more
carefullyMeasure the height to a tenth of
a cm
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ReasoningLike to bake
Thought it was interesting that yeast makes dough rise
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ExtensionsTest other factors that effect
yeast fermentation, like:oTemperatureoAmount of sugar
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Acknowledgements Mrs. Po Preparing solutionso Helping
Parentso Bought ingredients
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2010. <http://www.io.com/~sjohn/bread.htm>.
"Fermentation." Utah State University: Intermountain Herbarium. Web. 04 Oct. 2010.
<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>.
"Yeast Fermentation in Baked Goods." Dakota Yeast. Web. 20 Dec. 2010.
<http://www.dakotayeast.com/help-fermentation.html>.