An Internal Investigation Of The Digestion Of Starch By Salivary Amylase

Biology Internal assessment
The digestion of starch by salivary amylase

Personal engagement
I was led to this topic two weeks before introduced to the IA. One night, I woke up because I was hungry; I walked into kitchen and ate a piece of rice cracker, the taste was very dull and unflavoured. The next day, during the afternoon, I ate another rice cracker, but this time the taste was different, it tasted slightly sweet. I wanted to investigate why this was the case.
I contemplated about it and concluded that the reason for the difference in taste had to be related to the amount of saliva present in my mouth. To investigate this conjecture, I did some research and found that my hypothesis was correct; the amount of saliva affected the breakdown

According to a scientific, peer reviewed journal, published in Plos One, there are 2.64mg of amylase per ml of saliva [6]. Amylase converts starch, which is a polysaccharide (molecule with multiple glucose molecules attached together with chemical bonds), into simpler molecules such as maltose, which is a disaccharide, and dextrin, which is smaller chain of polysaccharide [2,8]. Amylase enzymes do it, using a process called hydrolysis where they break the chemical bonds between the connected monomers in the starch with the use of water. With the help of salivary amylase complex starch molecules are converted into simpler molecules

Iodine can detect starch, so I will use it to see how much starch will be present on each treatment and this will allow me to find how amylase concentration will affect the breakdown of starch. I will put 0.5ml of potassium iodide solution of 0.0005molL-1 on each of the treatments to see how the colour of the solution will change. In theory, when potassium iodide dissolves in water, the iodine ions react with starch, which produces a blue colour [9,10]. The negatively charged iodine ions go between the spherical holes of the starch compound and alters the energy level of the molecules. This results the compound absorbing a different wavelength of light, hence changing the colour [9]. Logically, the expectation is that the higher the concentration of saliva, the more breakdown of starch will occur and a brighter shade of blue will be produced because less starch will be detected by the iodine