Pectinase Lab

Procedure:

Preliminary Lab:-

1. Cut a slice of an apple and use the mortar and pestle to crush it and get a paste.
2. Fill the apple past in a measuring cylinder until it measures 15 ml and then pour it into a test tube using a spatula to make sure that all of the 15 ml of apple paste reaches the test tube.
3. Repeat step one and two, so that you have two test tubes with 15 ml of apple sauce.
4. Pour hot water from the kettle into 2 beakers. Pour cold water into it to lower the beakers to lower them to the temperature you need them at.
5. Once the water is + or - 3° away from the temperature it is needed to be, add 8 drops of Pectinase to one test tube and 8 drops of water to the other.
6. Keeping a thermometer in each test tube, place the test tubes into the beakers and keep them in for 10 minutes. During these 10 minutes, you must maintain the temperature of the test tubes by adding cold or hot water to the beakers.
7. During these 10 minutes also spread the cheese cloths into two different funnels and place the filters above a measuring cylinder for each.
8. Once the 10 minutes are over, remove the test tubes out of the beakers and filter the paste through a filter paper into the measuring cylinders respectively. Use a stirrer to ensure that all possible juice is squeezed out.
9. Measure the volume of the liquid in each cylinder and record it in your data table. Use the results from the other groups at different temperatures to compile your data.

Final Lab:-

1. Measure 15 ml of apple sauce using a measuring cylinder and pour it into a beaker.
2. Repeat step number one so that you have two beakers with 15 ml of apple sauce.
3. Place an electronic thermometer’s rod in each of the two test tubes and place the two test tubes in a controlled water bath, until the temperature of the apple sauce reaches the desired temperature.
4. Remove the two test tubes from the controlled water bath and place them in the plastic bowl.
5. Add 8 drops of pectinase in one test tube and 8 drops of water in the other.
6. Hold the two test tubes in the plastic bowl for 20 minutes. During these 10 minutes, you must maintain the temperature of the test tubes by adding cold or hot water to the plastic bowl. Also make sure to keep the thermometer rod in the apple sauce and not touching any part of the test tube.
7. During these 20 minutes also spread the cheese cloths into two different funnels and place the filters above a measuring cylinder for each. Use water to moisten the cheese cloth so that it sticks to the sides of the funnel.
8. Once the 20 minutes are over, remove the test tubes out of the beakers and filter the apple sauce through a filter paper into the measuring cylinders respectively. Use a stirrer to ensure that all possible juice is squeezed out, making sure not to let any of the apple sauce to fall outside or into the measuring cylinder.
9. Once all of the juice has been collected in the measuring cylinder, read the volume of the apple juice in each measuring cylinder and record it in a data table.
10. Repeat steps from 1-10 again for temperatures  20°C , 30°C, 40°C, 50°C, 60°C & 70°C.

Changes made for final lab & reason: 

• Mashed apple paste is hard to pour into a measuring cylinder and measure it due to its thick semi solid state. Thus, instead of mashing the apple ourselves and making the applesauce, we were provided with ready-made applesauce. This saved us time and energy and gave us a more liquid-like solution making it easier to pour the apple sauce and made the experiment easier to conduct. This gave us a more accurate measurement while finding the volume of the apple sauce.
• The human body generally takes 3 – 4 hours to digest its food and 10 minutes would not give the petinase ample amount of time to act on the apple juice. Thus we chose to alter the time from 10 minutes to 20 minutes, so that the pectinase had enough time to act on the apple juice.
• The Cheesecloth was moistened in the final lab as that would help it stick to the sides of the funnel and not allow any filtrate to fall through.

Data Table:

Graphs and Analysis

Graph 1

Analysis: This graph shows the comparison between the juice produced by the Pectinase and the Water(Control), at different temperatures. In this graph we can see that pectinase has produced more apple juice than water at temperatures ; 20, 40, 50 & 60 (°C). We gained these results probably because these temperatures are close to the temperature in the mouth which is the optimum temperature of the environment that pectinase can work best in. Although, it seems like our results for 60°C is erroneous as 60°C is not close to the optimum temperatue that pectinase can work in. this could be due to some errors accidently performed by a student. We can see that at 70°C, water has produced more apple juice than pectinase. This could be because the pectinase stopped acting on the apple sauce as a result of getting denatured due to the high temperatures.

Graph 2

Analysis: This graph shows the amount of apple juice produced by the pectinase at different temperatures. In this graph we can see that pectinase works best at 40°C and the worst at 60°C. Although I feel the result at 60°C is anomalous as the least production of apple sauce by pectinase should be at 70°C. This is the point where the pectinase is denatured due to the high temperatures which results in very little production of apple juice.

Conclusion: Our hypothesis stated that the body temperature of a human is between 30°C – 40°C. Thus, we predict that this is the optimum temperature range where the pectinase will produce the most amount of apple juice, was proved right, according to the results gained from this experiment. Since the pectinase has produced the most amount of apple juice at 40°C according to our results, we can conclude that 30°C – 40°C is its optimum temperature of the environment that pectinse can work best in.

Errors & Modifications:

1. The temperatures maintained were about ± 3°C of the desired temperature. This could lead to an anomalous result. This can be modified by placing the testubes in a controlled water bath, which is set at the desired temperature.
2. All the apple juice may have not made it through the cheese cloth, giving us an erroneous result for our reading for the volume of the apple juice produced. This can be modified by making sure to squeeze out all the apple juice from the cheese cloth or by using apple sauce in a more liquid state.
3. The time alotted for the pectinase to react on the apple sauce was not ample amount of time, thus giving us inaccurate results. This can be modified by increasing the time for the pectinase to react on the apple to 3 – 4 hours. This way we will get more accurate results.
4. The thermometers were placed in the bottom half of the test tube. Thus we did not know the temperatures at the top half of the test tube which also contained pectinase. Thus, the teperature at which the pectinse was acting on the top half of the test tube may not have been the temperature that was desired, giving us inaccurate results. This can be modified by placing a thermometer at the bottom of the test tube and at the top, reducing the chance of any inaccurate results.