Resumen de Articulos de Levaduras
How does temperature affect the fermentation of yeast?
In science, we stretched a balloon over the top of a bottle filled with sugar, warm water, and dry yeast. It inflated a little after a few minutes. We did the same thing with another bottle filled with sugar, cold water and dry yeast. The balloon didn 't inflate. Apparently fermentation occurs more in hot temperatures than in cold. Why is this?
Chemical reactions within yeast are facilitated by enzymes, which are large organic catalysts. Each enzyme has an "optimal temperature range" -- a temperature range at which it performs best. For many enzymes, the optimal temperature range is what we would perceive as warm -- about the same as normal internal human body temperature.
So: in the warm water, enzymes are within their optimal temperature range, and they catalyze chemical reactions more quickly, therefore the fermentation (which is a series of chemical reactions) proceeds more quickly.
http://www.rsc.org/Education/Teachers/Resources/cfb/
Effect of Temperature on Fermentation
Temperature changes have profound effects upon living things. Enzyme-catalyzed reactions are especially sensitive to small changes in temperature. Because of this, the metabolism of a poikilotherm, an organism whose internal body temperature is determined by its environment, is often determined by the surrounding temperature. Bakers who use yeast in their bread making are very aware of this. Yeast is used to leaven bread (make it rise). Yeast leavens bread by fermenting sugar, producing carbon dioxide, CO2, as a waste product. Some of the carbon dioxide is trapped by the dough and forms small “air” pockets that make the bread light. If the yeast is not warmed properly, it will not be of much use as a leavening agent; the yeast cells will burn sugar much too slowly. In this experiment, you will watch yeast cells respire (burn sugar) at different temperatures and measure their rates of respiration. Each team will be assigned one
In science, we stretched a balloon over the top of a bottle filled with sugar, warm water, and dry yeast. It inflated a little after a few minutes. We did the same thing with another bottle filled with sugar, cold water and dry yeast. The balloon didn 't inflate. Apparently fermentation occurs more in hot temperatures than in cold. Why is this?
Chemical reactions within yeast are facilitated by enzymes, which are large organic catalysts. Each enzyme has an "optimal temperature range" -- a temperature range at which it performs best. For many enzymes, the optimal temperature range is what we would perceive as warm -- about the same as normal internal human body temperature.
So: in the warm water, enzymes are within their optimal temperature range, and they catalyze chemical reactions more quickly, therefore the fermentation (which is a series of chemical reactions) proceeds more quickly.
http://www.rsc.org/Education/Teachers/Resources/cfb/
Effect of Temperature on Fermentation
Temperature changes have profound effects upon living things. Enzyme-catalyzed reactions are especially sensitive to small changes in temperature. Because of this, the metabolism of a poikilotherm, an organism whose internal body temperature is determined by its environment, is often determined by the surrounding temperature. Bakers who use yeast in their bread making are very aware of this. Yeast is used to leaven bread (make it rise). Yeast leavens bread by fermenting sugar, producing carbon dioxide, CO2, as a waste product. Some of the carbon dioxide is trapped by the dough and forms small “air” pockets that make the bread light. If the yeast is not warmed properly, it will not be of much use as a leavening agent; the yeast cells will burn sugar much too slowly. In this experiment, you will watch yeast cells respire (burn sugar) at different temperatures and measure their rates of respiration. Each team will be assigned one
References: De Schweinitz, Jean. (2009). Chapter 7. Majors Biology Laboratory Manual, (81-88). Iowa. Kendall Hunt Publishing Company. http://urbancaliber.hubpages.com/hub/Temperatures-Effect-on-the-Fermentation-of-Yeast