Effect of pH on the Reaction Time of the Enzyme Amylase

Presenter(s) Information(s)

Gaby Falter

Abstract or Description

Abstract

Enzymes are proteins that help speed up metabolism. One of them is alpha amylase, found in our saliva to help transform starch into simple sugars, to help with digestion. To find how fast complex sugars can be broken down by it, two experiments were conducted to determine the optimum pH for this to occur, and to confirm if the starch was converted into a simple sugar. Theoretically, alpha-amylase will reach its highest enzyme activity closer to pH 7.

Initially, to determine the rate of reaction, a test was completed on solutions containing starch, amylase, and iodine at different pH values. The mix of starch and iodine generated a dark blue color, which cleared once amylase was introduced. The time for this change to occur was measured and compared. This was followed by the application of the Benedict’s test, where the resulting precipitate helped confirm if the reaction occurred.

The results show that pH 9 was optimal because of the fastest time to observe a color change. Even though alpha-amylase was used, the used powdered version was a type of alkaline (higher pH) amylase, where the optimum pH is between 9 and 10.5. 

The experiment and results are important and can be applied in the food industry, especially during the brewing and fermentation processes. The iodine test can be used to determine if the breakdown of starch occurs and how fast. In a future experiment, if trying to determine if pH 7 is the optimum, actual saliva should be used.