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Laboratory Investigation

Student Materials



Student Materials


Introduction: Apple Juice


A Connecticut company is in the business of making and selling apple juice.  To make apple juice, apple sauce is strained through filters to remove the juice.  The company would like your help in testing the impact of different enzymes on the production of the apple juice. You will investigate the ability of these enzymes to remove more juice during this process and decide the most cost effective plan to increase juice production. The following is a list of the enzymes along with their prices:


                                    Pectinase:        $  50 per liter

                                    Cellulase:        $100 per liter


Enzymes are proteins that catalyze chemical reactions in the cells of all living organisms.  Enzymes control many vital functions in the cell, including the release of energy during the breakdown of nutrients into smaller molecules and the synthesis of complex cell materials from the small molecules.  In this lab you will work with two plant enzymes – cellulase and pectinase.



Your Task


You and your lab partner will design and conduct an experiment to determine which enzyme or combination of the two enzymes maximizes juice production.  Once you complete the laboratory investigation, you will evaluate which enzyme will be the most cost effective to use in juice production. 


You have been provided with the following materials and equipment. It may not be necessary to use all of the equipment that has been provided.


Suggested materials:


apple sauce                                                               droppers

pectinase enzyme                                                      stirring rods

cellulase enzyme                                                       graduated cylinder

funnels                                                                     access to tap water

filter paper                                                                paper cups

lab aprons                                                                 access to a watch or clock with a second

splash-proof goggles                                                access to a balance

paper towels for cleanup









 Designing and Conducting Your Experiment



1. In your words, state the problem you are going to investigate.  Write a hypothesis using an “If …  then … because …” statement that describes what you expect to find and why.  Include a clear identification of the independent and dependent variables that will be studied.


2. Design an experiment to solve the problem.  Your experimental design should match the statement of the problem and should be clearly described so that someone else could easily replicate your experiment.  Include a control if appropriate and state which variables need to be held constant.


3. Review your design to your teacher before you begin your experiment. 


Note: The enzyme(s) should be well mixed into the apple sauce to be effective.  Use 5-10  

drops of enzyme per 50 grams of apple sauce (approximately two ounces).


Safety notes:  As in any laboratory experiment, you must not eat or taste any of the         materials.  Students must wear approved safety goggles and follow all safety instructions.


4.  Conduct your experiment.  While conducting your experiment, take notes and organize your data into tables.


When you have finished, your teacher will give you instructions for cleanup procedures, including proper disposal of all materials.







Communicating Your Findings


Working on your own, summarize your investigation in a laboratory report that includes the following: