The effects of natural and chemical leaveners on the spoilage process of baked goods.
Judy Rhee, Sasha Jatskevich
Point Grey
Floor Location : J 031 D

Food spoilage and food preservation have been a topic of interest for industry, retailers and customers for many years. A complex combination of factors determines food “shelf life”. One of such factors could be the leaveners used in baking.
Our experiment objectives were to observe and record the process of spoilage in pizza dough made with different leaveners and investigate if leaveners affect the time frame of pizza spoilage. We hypothesized that if we bake pizzas using 3 different leaveners, then the pizza with yeast should spoil first, followed by pizza with baking powder, and then by pizza with baking soda, because pizza dough with baking soda contains the highest amount of acid. Baking soda and baking powder require/include acidic ingredients to activate the chemical reaction in pizza dough – vinegar or cream of tartar. To activate the same reaction, larger amount of vinegar than cream of tartar is needed. Acid acts as a mold inhibitor and therefore makes pizza dough resistant to spoilage.
To prove our hypothesis we baked 3 pizzas using the same ingredients for all 3 recipes with only one manipulated variable - the leavener. The samples were observed for the signs of spoilage over a course of 14 days by 2 independent researchers in four different environments (open-air indoor, open air outdoor, closed-air indoor, and closed-air outdoor). The observations were recorded daily in identical tables based on the list of standardized criteria. Our observations confirmed our hypothesis and demonstrated the following: yeast ‘indoor closed-air’ samples began to spoil well before the samples with other leaveners (around Day 6-10) and demonstrated significant signs of spoilage by the end of our experiment. Baking powder ‘indoor closed-air’ samples began to spoil around day 7-14. However ‘outdoor closed-air’ samples (placed outdoor for testing the effects of temperature on spoilage) didn’t grow any mold. The samples with baking soda did not show any signs of spoilage for the duration of the experiment in all research settings. These results are consistent with other studies on food spoilage that stated that mold typically grows within 4-10 days of a baked goods creation. Outdoor samples showed the following: yeast pizza dough developed minor signs of mold at day 10 and stayed the same through to the end of the experiment, while the baking powder sample and the baking soda sample remained unspoiled. These results are consistent with previous research on the effects of temperature on the growth of mold. There was a slight margin for error in our experiment as we had to open the containers to record the texture of the dough. This allowed some fresh air into the container environment, possibly affecting the results.
The results of our experiment allow us to conclude that different leaveners significantly affect the preservation process of pizza dough. Using leaveners without acidic ingredients makes pizza dough more prone to spoilage, while using leaveners that contain even mild edible acids allows for longer preservation time.