• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

To investigate the effect of cellulase on fruit juice extaction.

Extracts from this document...

Introduction

AS LEVEL BIOLOGY COURSEWORK TO INVESTIGATE THE EFFECT OF CELLULASE ON FRUIT JUICE EXTRACTION A METHOD An amendment was made to the suggested method for practical reasons. Instead of leaving the apple puree in the enzyme solution for twenty four hours at room temperature, beakers containing the samples were immersed for one and a half hours at 40oC in a thermostatically controlled water bath. B RESULTS Table of Results See over for table prepared for results and observations and completed during the experiment. Since the 0% enzyme immersion solution would not be expected to change fruit juice extraction, this datum was used as a control and fruit juice volume produced calculated by subtracting this baseline volume from the total observed at each enzyme concentration (see table below). The percentage of cellulase is the independent variable and the increased or decreased volume of juice produced is the dependent variable. % cellulase solution Total volume of apple juice (+ enzyme solution) produced cm3 Change in volume cm3 due to enzyme activity 0 10.3 + 0.0 0.5 15.2 + 4.9 1.0 15.8 + 5.5 1.5 10.1 - 0.2 2.0 17.2 + 6.9 C GRAPH (see graph paper over) ...read more.

Middle

and increasing enzyme availability. Increased concentration of enzyme provides more active sites for substrate binding. So long as excess substrate is available, the reaction rate increases in proportion to enzyme concentration (see over). If substrate is limited, an increase in enzyme availability does not result in increased reaction rate because active sites have no substrate to bind and the reaction rate plateaus. The experimental graph shows a tendency towards a plateau of the reaction rate with increasing enzyme concentration indicating that substrate concentration (i.e. apple cell wall cellulose) was limiting. However, a plateau was not actually reached as high enough enzyme concentrations were not used (see D 1 g below). D EVALUATION 1) Limitations of the Experimental Method a) Replicates No replicates were carried out. At least 3 sets of data should have been obtained in order to be certain that results are meaningful, to identify the trends and to identify anomalous results. b) Even Puree? The apple pulp could not be evenly pureed with the blender because the volume was too small. There were some lumps. This could have resulted in variation in the total surface area of apple presented to the different enzyme solutions and therefore in cellulose available for reaction. ...read more.

Conclusion

Pectins bind water tightly and therefore prevent loss of cell sap. c) Varying sources of substrate Different varieties of apple could be used using the same weight and consistency of puree for each experiment. The effect of storage and age of the fruit could also be investigated. d) Rate of extraction of juice This could be established by immobilising the cellulase - for instance in alginate beads mixed with the substrate in a column with an outlet at the bottom - and measuring the liquid produced per unit time under different conditions. The initial reaction rate could be measured by plotting volume produced against time and measuring the gradient of the asymptote at zero time. Initial reaction rates at different substrate concentrations could be plotted against substrate concentration to investigate Michaelis-Menten kinetics of the enzyme. A Lineweaver Burk plot of the reciprocal of initial velocity against the reciprocal of substrate concentration would give the Michaelis constant which gives an indication of the turnover rate of the enzyme. e) Conditions for optimum fruit juice extraction The experiment could be repeated with differing incubation times at the optimum temperature and pH (see a) above) to find the conditions under which maximum fruit juice extraction occurs. This would be the pilot stage of a design to produce apple juice commercially. ...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

    Investigating the effect of enzyme concentration on the activity of cellulase.

    5 star(s)

    its velocity will increase. Apparatus * 450cm3 of 2% concentration of cellulose (wall paper paste) - To make the wall paper paste solution, water was added to the dry paste flakes to make up the manufacturers recommended concentration of 2%.

  2. Marked by a teacher

    The use of pectinase in fruit juice production

    4 star(s)

    pH level suited to the enzyme by being equal to the natural environment of the enzyme pectinase. ii) Substrate Concentration - mass of the apple sauce. When there is an excess of enzyme molecules, an increase in the substrate concentration, produces a corresponding increase in the rate of reaction.

  1. Marked by a teacher

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

    3 star(s)

    This can be explained using kinetic theory. Kinetic theory is the idea that when a substance is heated, its molecules are supplied with more kinetic energy and therefore move around faster. In this experiment, as the temperature increases, Pectinase works on breaking down pectin at a much faster rate.

  2. Marked by a teacher

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

    3 star(s)

    For instance, if tomato juice did not have an effect on germination, then the results after tomato juice had been added would not be significantly different than the 0% concentration (no tomato juice added) result. The graph also shows that as the concentration of tomato juice increases, the results significantly differ from when there is less tomato juice (e.g.

  1. To investigate how temperature affects the concentration of vitamin C in orange juice (specifically ...

    Evaluation: I believe that the 7 cm3 of DCPIP used at 60? is an anomalous result as it doesn't seem to fit in. There is a decrease in the amount of DCPIP used except for that 7.

  2. The Effect of Concentration on Pectinase Using Apple

    One of the syringes will be used just for pectinase and the other just for distilled water to avoid contamination. The readings that will eventually be taken will be the volume of juice produced during filtration. The amount of juice will be recorded every 30 seconds for 5 minutes.

  1. The use of pectinase in fruit juice production

    This was done to allow the pectinase to breakdown pectin in cellulose cell wall and so the juice is releasesd. This was also one of the variables which were kept under controlled to give a fair experiment. * The volume of apple juice was measured every minute from both mixtures

  2. Investigate the effect of fruit variety on the extraction of fruit juice.

    main aim of this experiment was to solely compare the amount of juice produced from the apple pieces with pectinase and the apple pieces with distilled water. From looking at my results it also appears as though the rate of apple juice productivity from the apple pieces in beaker A is gradually increases.

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