Factors of Starch

Purpose The purpose of the lab is to determine how different factors affect the digestion of

starch. Starch is a type of complex carbohydrate with large polysaccharide molecules that are

made up of hundreds of glucose subunits. The digestion of starch begins in the mouth with the

enzyme amylase and continues in the small intestine. Maltose, a disaccharide, breaks down the large polysaccharide molecules. Maltase, also found in the small intestine, splits each maltose

molecule in to two glucose molecules that can be absorbed into the bloodstream.

The experiment will be performed by adding amylase to starch solutions under varying

conditions of temperature and pH. After an appropriate time, the solutions will be tested for the

presence of sugar. By adding Benedict's reagent to the various solutions, the presence of sugar will be determined depending on colour change. No colour change after several minutes mean

no sugar is present. Ultimately, the affects of temperature and pH of digestion of starch will be

examined.

Hypothesis It is predicted that a high level of acidity and temperature will increase digestion of

starch until the optimal is attained. When heat is applied, it results in the particles to collide;

increasing the rate of reaction. Enzyme activity and starch digestion will increase with

temperature until the optimal temperature is reached. Once the temperature is too high, the

enzyme denatures and starch digestion will decrease. Amylase also has an optimal pH at which it functions; if the pH is low, then the enzyme will denature and starch digestion will decrease.

Observations

Table 1- Effect of Temperature on Starch

Ice Water Room Temp. Warm Water Hot Water Colour Change with Benedicts Reagent Blueish + Blue-yellow ++ yellowish +++ none - Amount of Sugar Trace Little Sugar Some Sugar Zero

Table 2- Effect of pH on Amylase