At first the rate of reaction will increase dramatically yet at a too high temperature the proteins denature (and as enzymes are proteins they denature too). The optimum temperature for pectinase is between 45°C and 55°C. If a too high temperature is used the enzymes will denature. When enzymes are subjected to a too high temperature they denature, for pectinase this is at temperature over 55°C. If temperatures above 55°C are used they can result in off-flavours in the final juice therefore temperature over 45°C are rarely used. .
Hypothesis.
Pectinase breaks down the pectinase in plant cell walls to release the pectins (fruit juices are suspended pectins) it also increases the speed at which the juice is released.
Temperature increases the speed at which the pectinase breaks down the pectin therefore the juice is released at a greater speed.
Prediction. .
If I add 5ml of pectinase to 20g of apples I predict that the amount of juice will increase by 50%. If the apples are placed in a water bath at 50°C for 15 minutes I predict that the amount of apple juice should be 50% larger the amount released when the apples were placed in a water bath at 20°C for 15 minutes after the pectinase was added.
Test experiment.
I used three different types of commercial apples to see which would be best for my main experiment (the commercial apple which produced the highest amount of apple juice compared to its mass). I used Royal Gala', Pink Lady' and Empire' apples.
Method.
I thinly diced one half of each apple and then divided into two 100ml beakers (I used 100ml beakers so that there would be a larger surface area when the apples were in the water bath therefore more of the sliced apple would be heated), labelled with the type of apple and A' or B', I weighed each of the six beakers using an analogue balance and recorded the mass. In the beakers labelled A' I added 5mls of pectinase and to the beakers labelled B' I added 5mls of distilled water to make it a fair test.