I included the column with rate of collection because it will show how much the enzyme improves juice collection.
I included the column about the percentage more apple juice collected with pectinase to test the claim that pectinase will increase fruit juice yield by 20%.
Analysis of results
From my graphs and table I can see that pectinase dramatically increased fruit juice yield. From the table I can see that after just 1 minute, 4cm3 of juice was collected with pectinase and only 1.2cm3 was collected without.
From my first graph of amount of juice collected against time, the line for pectinase is much higher that that of without pectinase. The gradient for the graph with pectinase between 0 and 4 minutes is much higher than the gradient for that of without pectinase. After 4 minutes then the gradients become the same. This shows that pectinase increased the yield of fruit juice within a certain amount of time i.e. increased the rate at which juice can be collected.
My second graph of rate of juice collection against time shows that the pectinase increased the rate at which fruit juice was collected. At first the rate is very high for both lines but then they start to lower until the two lines converge. This shows that for both with and without pectinase, the rate of collection will decrease. The rate at which juice is collected is higher for pectinase for a certain amount of time then after 4 minutes it returns to a slower rate which is the same as the rate without pectinase.
My third graph shows that pectinase increased the yield of fruit juice between 200% and 300% which is far more than the 20% that was my prediction.
Conclusion
In conclusion I can see that pectinase increased the fruit juice yield and the rate at which fruit juice is collected. Pectinase does this because it breaks down a protein called pectin which holds together the cellulose found in the cell walls of the fruit. These pectin proteins bind the cellulose walls of different cells together and make the whole cell stronger. When you try and crush the apples and these pectins are still there, most of the cell walls will not break and the juice will remain inside the cell. With pectin gone however, the cellulose walls can be separated and this disintegrates the cell wall. Now the juice has to only pass through 1 cell wall to get out of the cell instead of passing through multiple cell walls.
My prediction was based on an industrial figure which is why the percentage increases I found were very high. In industry, only 150cm3 is added to 1 tonne of apples. I used a bigger ratio of pectinase: apple so my increase varied with that ratio.
Evaluation
Overall I think this experiment produced accurate and reliable results that can be used to reach a valid conclusion. My results were fairly accurate and there were few problems. The measuring cylinder I used to measure the volume of juice collected was the smallest cylinder available meaning that the volumes measured were very accurate. When I weighed my apples, the scales were accurate to 2.d.p which is very accurate.
My results were fairly reliable but not entirely. I did not repeat the experiment which could have lead to me not spotting anomalous results. Also the surface area of the apples is a factor which affects the rate at which juice leaves an apple (if you squash a whole apple, you’ll get less juice then diced apples). A way I could have got around this problem is to make sure I cut the chunks into certain volumes e.g. 1cm3 cubes. This wouldn’t increase the reliability of my results significantly but it would make a slight difference. Also I measured the juice every 1 minute which I don’t think is accurate enough. This is because the amount of juice collected changes quickly over the first few minutes and having readings every minute does not monitor this change effectively. I could have read the amount of juice every 30 seconds and that would have given me more
I didn’t encounter any problems while doing this experiment. Ways I could improve this experiment are taking more readings to improve reliability, this would increase my reliability a lot. I could monitor the surface area of the apple chinks which would improve my reliability slightly. I could have repeated the experiment to improve my reliability greatly.
This experiment is biologically significant because pectinase is used in the fruit juice industry. They need to maximise the amount of fruit juice from each apple and to do that, pectinase is needed as just demonstrated from my experiment.
Ideas for further study are investigating the ratio of apple to pectinase and seeing if that is proportional to the amount of juice collected. Also I could see if pectinase works with other fruits such as oranges and compare to see in which fruit pectinase works best.
