• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11

The use of pectinase in fruit juice production

Extracts from this document...


The use of pectinase in fruit juice production Introduction Pectinase is an enzyme which catalyses the breakdown of pectin in the cellulose cell wall in the plant cells. Pectin is a sticky polysaccharide which is embedded in the cell wall of the plant cells to hold cellulose together in place. It is the structural carbohydrate which gives the plant cell mechanical support and prevents the cell from bursting when water enters into the cell by osmosis. It is also insoluble due its structure and arrangement of its monomers which are simple sugars. The presence of pectin in the cellulose cell wall prevents the cell contents from leaving the cell. This minimises the yield of the fruit juice when the manufactures try to extract juice from fruit. Pectinase, like many enzymes, is a globular protein and its structure is maintained by hydrogen bonds, disulphide bridges and the ionic bond. Enzyme has a specific site called the active-site where substrate molecules bind to form enzyme-substrate complex. The shape of the active-site is so specific that only substrate which has a complementary shape can fit in. This is called lock and key mechanism and suggests that one enzyme can only catalyse one reaction. However, enzyme slightly changes its shape when substrate binds to its active- site. This process is known as an induced fit. Enzyme speeds up the rate of reaction by lowering the activation energy. ...read more.


The graph for the mixture with pectinase is a curve, the gradient of which is big at the beginning of the reaction and then the gradient becomes smaller for the rest of the reaction. The mixture without pectinase produced no apple juice so the graph is a horizontal line along the time axis. This indicates that the reaction is too slow or impossible without the presence of pectinase. At the beginning of the reaction, all the active-sites are available for substrates and the concentration of substrate is also at its maximum point. So a lot of enzyme-substrate complexes are formed and most products are produced. This is indicated by the slope of the graph. The graph at the beginning of the reaction is almost straight line (from minute 0 to minute 2) which shows the rate of reaction increases constantly. The gradient of the graph decreases two minutes after the initial reaction. This can be seen from the graph as the graph starts to flatten off. From minute 2 to minute 8, more and more substrate molecules are converted into products. Less substrate is available for active-sites. Not all enzymes area occupied with substrate which in turn leads to the less yield of product. We expect the graph to flatten off after 8 minutes. But this reaction could not give this shape because it needs a longer time for the experiment. ...read more.


Taking the average also minimises the uncertainty and inaccuracy. The experiment was not repeated either. By repeating the experiment, we can take average result for individual test and thus can obtain a more reliable result. Besides all these limitations, the apple juice sauce we used was already cooked. We did not know which part of apple contained in the sauce. For example, thicker tissue will take longer to be broken down while thinner tissue will take shorter time. This in turn might give us different volume of apple juice per unit time. We also did not know the type of apple used. Different types of apple might give us different yields due different types of tissues which might need different conditions for enzymes to work on. Conclusion The reliability and the precision of the result is lower in this experiment. Other possible coursework 1. The effect of different temperatures on the activity of enzymes to find out the best economic condition for the industry 2. The effect of different pH on the activity of enzymes to find out the best economic condition for the industry 3. The effect of different concentrations on the activity of enzymes to find out the best economic condition for the industry 4. The effect of enzymes on cooked and uncooked apple sauce to find out which gives the most yield 5. The effect of enzymes on different types of apples to find out which gives the most yield 6. The effect of enzymes on ripe and unripe apples to find out which gives the most yield ?? ?? ?? ?? 11 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    Effect of temperature on the enzyme pectinase in fruit juice production.

    3 star(s)

    so that a good quality, clear juice is obtained which retains its stability when concentrated. (Picture taken from Reference 1 ) Pectinase is the name of the enzyme used industrially in obtaining juice from a fruit. It works by breaking down pectin between fruit cells which 'unglues' them so they can slip past each other, therefore releasing the fruit juice.

  2. Marked by a teacher

    The Effect of pH on Pectinase

    3 star(s)

    If this is not controlled then the variable of enzyme concentration will not have been controlled. If there were an increased number of enzymes then the reaction would take place faster than the other reactions and I would have made the test unfair as I could not tell if it

  1. Marked by a teacher

    An investigation into the inhibiting effect of tomato juice on the germination of cress ...

    3 star(s)

    Mutations occur naturally in about 1 in a million bases copied. Some environmental factors such as radiation increase the rates of mutations. Part of the genetic code of the tomato plant could have been deleted or substituted, making a mutated genetic code that provided the information to produce the inhibitors.

  2. Marked by a teacher

    The use of pectinase in fruit juice production

    3 star(s)

    Pectinase Enzymes are used in the processing of non-citrus fruits (such as apples) to maximise the production of clear juice. Most fruits contain pectins and other. Pectins hold the fruit cells together like glue to hold the cell wall together, to glue cells together and result in poor liberation of juice during pulping.

  1. The Effect of Concentration on Pectinase Using Apple

    The water bath could be set at any temperature as long as it remained constant. 1 Stopwatch An accurate stopwatch that gives times to the nearest millisecond will be used to time how long the test tubes are to

  2. An experiment to find of the isotonic point of root vegetables cells in contents ...

    In the 0.5 M sucrose solution the width and mass increased but the length decreased. This was quite surprising as you would expect the incipient plasmolysis to occur at this stage where the % presence of water and sucrose levels is equal.

  1. Uses of Enzymes - Pectinase and fruit juice production

    In these applications, they can improve texture, appearance and nutritional value, and may provide better flavors and aromas.

  2. An investigation into the effect of varying pH on the yield of apple juice ...

    passes into the measuring cylinder is not influenced by obstructions in the plastic funnel. This method uses as much of the apple as possible where as it would be difficult to use a knife to cut around the core without wasting rather large sections of the apple.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work