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The aim of the investigation is to find out what effect temperature has on the activity of pectinase when used in apple juice production.

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Practical Investigation: Effect of temperature on effectiveness on the Activity Pectinase Aim The aim of the investigation is to find out what effect temperature has on the activity of pectinase when used in apple juice production. Hypothesis And Scientific Reasons I predict the higher the temperature the greater the volume of juice production until a certain temperature where the enzyme denatures. There will also be a temperature where the enzyme works best; this is known as the optimum temperature. This is due to various reasons, ranging from the enzyme's structure (shape), its properties and its size. One of these is that the higher the temperature the more kinetic energy the pectinase has which means more movement and a higher chance of collisions between pectin and pectinase. Enzymes catalyse substrates through the fact that the substrates collide with the enzyme causing the substrate to combine with the enzyme forming the enzyme-substrate complex. Enzymes are globular proteins. They have complex tertiary and often quaternary structure in which polypeptides are folded around each other to form a roughly spherical or globular shape. The overall 3-Dimensional shape of an enzyme molecule is very important: if it is altered, the enzyme cannot bind to its substrate and so cannot function. ...read more.


Results Table Showing The Volume Of Juice Produced. Temperature (oC) Volume Of Juice Produced (cm3) Repeat 1 (cm3) Repeat 2 (cm3) Average Volume Of Juice (cm3) Control (cm3) 20 2.4 1.6 2.00 2.00 0.00 30 2.6 2.15 4.25 3.00 0.20 40 1.6 1.80 1.30 1.57 0.30 50 1.8 2.15 3.15 2.37 0.30 60 2.0 2.80 2.25 2.35 0.25 70 1.8 0.70 2.05 1.52 0.35 75 1.2 0.10 0.75 0.68 0.35 Table Showing Percentage Increase Temperature (oC) Average Volume Of Juice (cm3) Control (cm3) Percentage Increase (%) 20 2.00 0.00 - 30 3.00 0.20 1400 40 1.57 0.30 423 50 2.37 0.30 690 60 2.35 0.25 840 70 1.52 0.35 334 75 0.68 0.35 94 Analysis Although care was taken to obtain the greatest possible accuracy the results are not accurate enough to fully up hold the hypothesis. Between 20oC and 30oC my hypothesis is accurate as the average volume of juice produced goes up from 2.00cm3 to 3.00cm3 with the 10oC increase in temperature. However the average volume then decreases to 1.57cm3 at 40oC and then increase again to 2.37cm3 at 50oC. From this point the results seem to follow the hypothesis as the average yield of juice decreases as more of the enzyme is denatured at the higher temperatures. ...read more.


One improvement that could be made is to make sure that the apple is only chopped right before the experiment is carried out as for some of the experiments a apple that had been cut in half the day before was used the following day, which no doubt contributed to the anomalous results. To further extend research into the effects of temperature on pectinase there are many possible experiments. The effect of temperature on the rate of enzyme activity could be useful to draw further conclusions on how pectinase activity is affected by temperature. Research into the optimum ph for an enzyme to operate as well as the temperature, would give those in the biotechnologies industry the ideal information for the use of enzymes in for example washing up liquid. It would be very simple to modify this experiment that looked at the effects of temperature, to look at the effects of pH. If a chosen temperature (around 40oC) was used and substrate concentration and enzyme concentration were controlled properly then the experiment could be modified to look at the optimum operating temperature for pectinase. If the optimum temperature and pH for every enzyme in living organisms then it would give a great insight into reactions within the environment around us. Mursil Tafsirullah 12/DR2 Biology: Assessed Practical ...read more.

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