Make more juice from an apple
Compare juice recovery from equal portions of finely processed apple. Enzyme and control receive identical mixing, warming and filtration.
Use these original S&T teaching drafts after a teacher or technician has piloted the exact product, substrate and assay. Recipes and timing targets are proposed starting conditions, not validated performance claims. Review current SDS and institutional guidance; wear eye protection, avoid enzyme aerosols and splashes, and keep powders under technician control. No tasting. Keep controls at the same final volume, pH, temperature and stirring conditions. Plan reagent-specific waste disposal.
Pectinase in nature
Pectin helps organise plant cell walls and the middle lamella between neighbouring cells. Plants remodel pectin during growth and fruit ripening. Microorganisms produce pectin-degrading enzymes too. Commercial pectinase preparations may contain several activities, so the products depend on the formulation.
What chemical reaction does it catalyse?
Enzymes speed up a reaction without being consumed in the overall process. The preparation, accessible substrate and reaction conditions determine what you can measure.
Industrial applications
Fruit processors use pectinases to assist juice extraction, reduce viscosity and clarify juice.
Experiment overview
Compare juice recovery from equal portions of finely processed apple. Enzyme and control receive identical mixing, warming and filtration.
Equipment and materials per working group
- Two 50 mL beakers, two matched funnels and filters
- Fresh unsweetened apple purée from one well-mixed batch
- Pectinase liquid and water
- Balance, measuring cylinders and pipettes
- 40°C water bath and timer
Plan a class of 30
Use 10 working groups of three. Multiply the per-group quantities in this guide by 10, then allow an appropriate preparation reserve. Keep concentrations unchanged when scaling. Assign a timer, a practical operator and a recorder, then rotate roles. Set up teacher-prepared comparison samples in advance where a reaction takes longer than the lesson.
Teacher and technician preparation
- Use a single fruit batch and note its pH. Pilot the same variety and preparation intended for class.
- Start with 10 g purée plus 0.5 mL liquid pectinase, corresponding to a generous classroom trial dose. The control receives 0.5 mL water.
- Trial 10-minute and 20-minute treatments. For a strict short lesson, prepare a longer-treated pair before class and label its actual treatment time.
Use enough working enzyme to make a clear comparison in the intended time window. Do not automatically add more concentrate: reactions can finish before measurement, stocks can alter pH or background colour, and some substrates remain slow even at a high dose. Pilot the proposed recipe, then record the final preparation and dilution on the results sheet.
Step-by-step class method
- Label two beakers ENZYME and CONTROL and weigh 10 g well-mixed purée into each.
- Add 0.5 mL pectinase to ENZYME and 0.5 mL water to CONTROL.
- Mix each with its own clean stirring rod for the same period.
- Place both in a 40°C water bath; start the timer.
- Observe texture at 5 and 10 minutes without interpreting warming alone as enzyme action.
- Transfer each entire sample into a matched filter and funnel above a measuring cylinder.
- Collect filtrate for the same fixed period, for example 5 minutes, and record both juice volumes.
- Repeat or compare class-group results; discuss fruit variability and filter differences.
What should students look for?
The enzyme may increase juice recovery or improve flow, but a 10-minute contrast is not guaranteed for every fruit or preparation.
Interpretation and troubleshooting
Do not compare samples with unequal chopping, temperature, filter area or collection time. A clear endpoint in 5–10 minutes should be confirmed in a technician pilot.
Questions for the class
- What changed in the enzyme-treated sample compared with the control?
- What bond or substrate does this enzyme act on?
- Which conditions did we keep the same, and why?
- Could colour, pH, warming, stirring or background sugars explain part of the result?
- What would you measure or change in a follow-up investigation?
Your investigation sheet
Name: ____________________ Group: ______ Date: __________
Prediction: _______________________________________________________
Enzyme preparation / batch: ________________________________________
Final working dilution and dose: ____________________________________
Substrate: _______________ pH: ______ Temperature: ______ °C
| Time / min | Enzyme + substrate | No-enzyme control | Enzyme-only blank / notes |
|---|---|---|---|
| 0 | ________________ | ________________ | ________________ |
| 2 | ________________ | ________________ | ________________ |
| 5 | ________________ | ________________ | ________________ |
| 10 | ________________ | ________________ | ________________ |
| Later: ___ | ________________ | ________________ | ________________ |
Conclusion supported by our control: _________________________________
One limitation and one improvement: __________________________________
Background sources and product details
This is an original teaching adaptation. External methods establish useful principles and assay formats; they do not validate the suggested doses for S&T preparations.