Yeast Reproduction in Sugar Substitutes Tracey Merz Grade 9

Problem Will yeast reproduce using different sugar substitutes? Rationale: This project was chosen because I wanted to do a project which involved baking, and I am also interested in working with yeast.

Research Yeast are fungi. Fungi feed off of other things, like animals do. When food is available, the yeast cells digest it. The food (such as sugar) is burned off by the process of cellular respiration. Carbon dioxide is given off by cellular respiration, so the amount of carbon dioxide gas produced shows how much cellular respiration is taking place. Yeast is able to metabolize maltrodextrin and dextrose, which are both fillers which are used in artificial sweeteners to increase their volume.

Research, Continued While the chemical makeups of saccharin, aspartame, and sucralose are all different to that of sucrose, sucralose is the closest Sucrose Sucralose Saccharin Aspartame

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

Materials -Yeast: 10 mL for each solution -Water: 20 mL for each solution -Sugar Substitutes/Sugar: 2 g for each solution -Graduated Pipettes -Graduated Cylinder -Thermometer -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

Procedure Part One: -The water was heated to 40 degrees Celsius. -The yeast and water were combined, and stirred vigorously until foaming. -A yeast/sugar solution was made for each type of sugar to be tested. -Each yeast solution contained 20 ml of water, 2 g of sugar or sugar substitute, and 10 ml of the yeast and water mixture. -The yeast/sugar solutions were mixed until combined. -A sampling of each yeast/sugar solution was pumped into a syringe to the top and the end was sealed with duct tape. -The amount of carbon dioxide produced at 0 minutes, 10 minutes, 20 minutes, and 30 minutes was recorded.

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

Procedure, Continued Independent Variable: Dependent 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 is 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 and type of ingredients

Data

Data P Value: 0.724345 No Sugar Sucro-se Aspar-tame Sacc-harin Sucra-lose Average 0.216544 0.471899 0.352271 0.3215269 0.324376 Standard Deviation 0.028101 0.102271 0.1115269 0.094376 Confidence Level 0.300109 0.038945 0.141738 0.1545656 0.130795 P Value: 0.724345

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. The experiment also showed that the three sugar substitutes don’t show difference from each other, even though aspartame and sucralose are different from sugar.

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 carcinogen. This is a possible place or error and could be tested by performing further tests and seeing if the results are still the same.

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. <http://venturpreneur.com/story-2-can-sugar-substitutes-make-yeast-grow/>. Karney-Grobe, Scott. “Yeast Reproduction in Sugar Substitutes.” Science Buddies. Seagate, 2006. Web. 8 Nov. 2009. <http://www.sciencebuddies.org/fair-projects/_ideas/_p005.shtml>. McKesson Health Solutions. “Sugar Substitutes.” University of Iowa Healthcare. U of Iowa Hospitals and Clinics, 2003. Web. 8 Nov. 2009. <http://www.uihealthcare.com///.html>. “White Bread.” Bread-Maker.net. N.p., 2006. Web. 8 Nov. 2009. <http://www.bread-maker.net/maker-recipes/White-Bread.htm>. Woodland, Lindsey. “How to Cook with Yeast Using Sugar Substitutes.” EHow. N.p., n.d. Web. 8 Nov. 2009. <http://www.ehow.com/_5552888_cook-yeast-using-sugar-substitutes.html>.