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Use of Pectinase in the production of fruit juice: Quantifying enzyme concentration on amount of apple juice produced

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Use of Pectinase in the production of fruit juice: Quantifying enzyme concentration on amount of apple juice produced Marunya Hilda K. Plan Enzymes are biological catalysts which are protein in nature. They facilitate and speed up chemical reactions. Enzymes bind temporarily to one or more of the reactants (substrate) of the reaction they catalyze, to form enzyme-substrate complexes, as shown in the diagram below: In doing so, they lower the amount of activation energy needed and thus speed up the reaction, as illustrated in the graph below: Enzyme activity can be analysed quantitatively. One of the ways is investigated in this activity. Aim: * The aim of this experiment is to quantifying enzyme concentration on amount of apple juice produced. Fruit juice can be extracted from a wide variety of fruits. This can be done by simply squeezing the fruits but it is more common to use enzymes to increase the volume of juice produced and the speed of extraction. The enzymes which are used, both commercially and in this experiment, break down the cell walls within the fruits and release liquids and sugars. Fruit cell walls are very complex molecular structures and to get the maximum breakdown of the compounds found in them, fruit juice companies use a variety of different treatments and enzymes to maximise the yield of juice. ...read more.


2. Chop medium sized apple into very small pieces, and distribute equally into the 'Pectinase' and 'control' beakers, adjusting the pieces until the masses of the two beakers are approx the same. I am going to measure the amount of apples, so that I use the same mass for each experiment. Measure 10cm� of water and squirt onto the apple pieces in the beaker marked 'control' (i) Measure 2cm� of Pectinase and 8cm� water to make (ii) Measure 3cm� of Pectinase and 7cm� of water to make (iii) Measure 5cm� of Pectinase and 5cm� water to make (iv) Measure 7cm� of Pectinase and 3cm� water to make (v) Measure 10cm� of Pectinase and no water to be added to make All of the above in different runs (five times for each run) to be squirt onto the apple in the beaker marked 'Pectinase'. (Eye protection to be worn). 3. Stir the contents of each beaker with a separate glass rod 4. Incubate the beakers for 15-20mins in the water bath. Label two measuring cylinders 'Pectinase' and 'control' and place in the top of each filter funnel fitted with a coffee filter paper 5. ...read more.


However this did not solve the problem completely so I decided to saturate the filter papers with 1cm� of water each time before I use them, so that they would not absorb any of the juice. * I also had to change the time intervals in which I was recording the results. This was because I started getting successive drops of juice after a while, so I decided to change the time interval from every minute to every five minutes. * I was just about getting the same amount of juice in each run every time, thus I decided to cut the number of runs from five to four. Conclusion Referring to the concentration-volume graph, we can see that the graph increases as the concentration increases, but because Pectinase works at an optimum concentration of 4moldm �, the graph is very steep between 2moldm � and 4moldm �. As the enzyme concentration increases the rate of the reaction increases linearly, because there are more enzyme molecules available to catalyse the reaction. At very high enzyme concentration the substrate concentration may become rate-limiting, so the rate stops increasing. Normally enzymes are present in cells in rather low concentrations, and thus my hypothesis was correct ...read more.

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