How Heat Affects Lipase

Topics: Enzyme, PH, Enzymes Pages: 5 (1180 words) Published: April 27, 2013
Factors Affecting Enzyme Action
Term 1 Biology
Nicole Goosen

Table of Contents
Risk assignment:4
Personal Protective Equipment:4

How is the human body able to digest the food that you eat? How quickly your body digests your food? This is because the human body contains enzymes that are the biological substance, a.k.a proteins, that act as catalysts and help complex reactions occur. There are many different enzymes that each have different specific functions. The enzymes include: diastase, pepsin, lipase, catalyse and urease. Lipase is an enzyme found in the digestive tract that catalyses the break down of fats into individual fatty acids that can be absorbed into the bloodstream. This enzyme will be used in this EEI. The purpose of this EEI is to test the rate in which lipase reacts to different variables such as temperature and pH. Enzymes are found in foods, epically raw foods such as meat, but cooking foods destroys any enzyme activity, including lipases. If the temperature changes then the pH levels will change. The optimum temperature is 37°, that is the average temperature inside the human body; the optimum pH level is 8.0. (Corporation, 2013) The purpose of this EEI and experiment is to calculate the rate in which the pH level of milk changes after it has been heated and the heated lipase is added. Four different temperature will be tested to create the most accrete results possible. When lipase is heated, it becomes a fatty acid that destroys itself, so when the lipase is heated and then added to the heated milk, it rate in which the pH level changes should be high and fast. If the lipase and milk is heated above its optimum temperature (42°) then combined, the pH level will change much quicker and the change in pH levels will be much more clear.

* Full cream milk
* Phenolphthalein
* Sodium Carbonate
* Test tubes
* Ice cream container
* Test tube stand
* Kettle
* Thermometer
* Inferred thermometer
* Pipette
* Heat proof mat
* Stop watch
* Lipase
* Stirring rod
* Beaker


1. Place 5mL of full cream milk and 3 drops of 1% phenolphthalein into one test tube. 2. Add 0.5mL of sodium carbonate incriminates into the milk solution until it turns pink. 3. Warm water bath to 37°C.

4. Prepare 12mL of 3% Lipase solution in a separate test tube in a container of room temperature water and warm the solution to 37°C. 5. Use a clean pipette to transfer 3mL of lipase solution into the milk test tube and stir well whilst keeping the temperature at 37°C. 6. Wait 10-15 minutes for clear evidence of change within the solution then record results. 7. Repeat steps 1-6 with different temperatures.

Risk assignment:
Substance | Hazardous substance yes or no | Risk rating | Lipase| Yes| 2|
Full cream milk| No| |
Phenolphthalein| Yes| 2|
Sodium Carbonate | Yes| 2|

* Spillage
* Heat and cold
Personal Protective Equipment:
* Safety glasses
* Vinyl gloves
* Lab coat
* Enclosed leather shoes


Temperate (C°) | 27°| 32°| 37°| 42°|
Time (seconds)| 90 seconds| 50 seconds| 20 seconds | 5 seconds |

Figure 1:

During the practice trial for the experiment did not work and the non-existent results where discarded, as they did not sure and change in pH levels. In this experiment, the group was trying to record the time it took for the lipase to cause a chemical reaction in the milk. Many components went wrong during the practice trials, such as, the milk started to expire and curdle causing the reactions not to take place, this could be due to the possibility that a reaction had already taken place within the milk and destroyed all traces of...
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