1. Yeast Reproduction in Sugar Substitutes Tracey Merz Grade 9

2. Problem Will yeast reproduce using different sugar substitutes? Rationale: This project was chosen because I wanted to do a project which involved baking, specifically one working with yeast and one that tested leavening agents.

3. Research Yeast  Fungi  Heterotrophic Consumes food for energy Food is burned off in cellular respiration  A bi-product is carbon dioxide Yeast is able to metabolize the fillers in artificial sweeteners.

4. Research, Continued While the molecular arrangements of saccharin, aspartame, and sucralose are all different to that of sucrose, sucralose is the closest. Sucrose Sucralose Saccharin Aspartame

5. Hypothesis If a sugar substitute is used, then less carbon dioxide will be produced. Of the three types of sugar substitutes, sucralose will produce the most carbon dioxide.

6. Materials -Yeast: 10 mL for each solution -Water: 20 mL for each solution -Sugar Substitutes/Sugar: 2 g for each solution -Graduated Pipettes -Duct Tape -Graduated Cylinder -Thermometer -Bread Machine -Bread Ingredients: - 236.5 mL (1 3/8 cup) Water -28.4 g (2 tablespoons) Butter -919.7 g (4 cups) Flour -28.4 g (2 tablespoons) Sugar/Sugar Substitute -28.4 g (2 tablespoons) Dry Milk -8.3 g (1 ¾ teaspoons) Salt -10.7 g (2 ¼ teaspoons) Yeast

7. Procedure, Part One 1.A yeast solution was prepped with warm water and was agitated. 2.A 1:2 yeast-sugar solution totaling 30ml was made for each solution tested. 3.A sampling of each yeast-sugar solution was pumped into a graduated pipette to the top and the end was sealed with duct tape. 4.The amount of carbon dioxide produced at 0 minutes, 10 minutes, 20 minutes and 30 minutes was recorded.

8. Procedure, Part Two 1.All of the bread ingredients were added to the bread machine. The Basic Cycle was selected, as was the Light Crust option. 2.When the baking cycle ended, the bread was allowed to cool to room temperature before being sliced. 3.The height of the bread, the shape, and the amount of air bubbles were observed.

9. Procedure, Continued Independent Variable:  Type of sugar substitute the yeast was fed Dependent Variable:  How the yeast reacted to the sugar substitute (how much carbon dioxide was created) Control:  When no sugar was added at all Constants:  Part One: Amount of yeast solution, way of collecting the solution, temperature of water, amount of sugar substitute, time to collect carbon dioxide  Part Two: Bread machine, amount of ingredients used, type of ingredients used

10. Data

11. No SugarSucroseAspartameSaccharinSucralose Average0.2165440.4718990.3522710.32152690.324376 Standard Deviation 0.2165440.0281010.1022710.11152690.094376 Confidence Level 0.3001090.0389450.1417380.15456560.130795 Data, Continued

12. Conclusion The hypothesis was partially supported. The hypothesis stated that sugar substitutes would create less carbon dioxide than normal sugar. By general average, this is true. The hypothesis stated that sucralose would perform the closest to sugar, but the results showed that saccharin was the closest.

13. Conclusion, Continued The experiment showed saccharin to be equal to sugar in carbon dioxide production. Sucrose and sucralose have the closest chemical structure, so it seems that they should be the most similar, not saccharin. Saccharin has a benzene ring which the yeast shouldn’t be able to metabolize because it is a possible carcinogen.

14. Possible Error and Improvement Saccharin should not be able to perform equivalent to sucrose according to research  Possible place of error  More trials could be done to see if the results hold true Other possible improvements:  Trying other brands of sugar substitutes  Making sure all of the bread ingredients are exact

15. Thanks Thank you for listening! If you have any questions, feel free to ask. “Can Sugar Substitutes Make Yeast Grow?” Venterprener: The Diet Entrepreneur. N.p., 2007. Web. 8 Nov. 2009.. Karney-Grobe, Scott. “Yeast Reproduction in Sugar Substitutes.” Science Buddies. Seagate, 2006. Web. 8 Nov. 2009.. McKesson Health Solutions. “Sugar Substitutes.” University of Iowa Healthcare. U of Iowa Hospitals and Clinics, 2003. Web. 8 Nov. 2009.. “White Bread.” Bread-Maker.net. N.p., 2006. Web. 8 Nov. 2009.. Woodland, Lindsey. “How to Cook with Yeast Using Sugar Substitutes.” EHow. N.p., n.d. Web. 8 Nov. 2009..