Comparison of samples-Part 1

1. Equipment list:

• Test tubes
• Test tube rack
• Glass rod
• Spatula
• Pestle and Mortar
• Pipette
• Food samples
• Distilled water
• DCPIP solution ( 1gram DCPIP, 100ml Water)

1. Make an extract from the fruit/veg, using a pestle and mortar, to create enough to fill a test tube a 2/3 cm deep. Add to stand for a few moments.
2. Add a drop of the DCPIP solution, mix, and observe.
3. If the blue of the DCPIP disappears, Vitamin C is present.

RESULTS

FRUIT

Strawberry: DCPIP turned colourless

Red grape:DCPIP turned purple/red-Probable discolouration, no reaction?

Apple: DCPIP turned purple-Probable discolouration, no reaction?

Banana: DCPIP turned purple-Probable discolouration, no reaction?

Orange: DCPIP turned colourless

Pear: DCPIP turned purple-Probable discolouration, no reaction?

Green Grape: DCPIP turned purple-Probable discolouration, no reaction?

VEGETABLE

Potato: DCPIP did not change colour

Turnip: DCPIP did not change colour

Carrot: DCPIP changed to a lighter shade of blue-Probable discolouration, no reaction?

Courgette: DCPIP changed to a lighter shade of blue-Probable discolouration, no reaction?

Green Beans: DCPIP did not change colour

Tomato: DCPIP changed to be colourless.

REFLECTIONS

1. Mistook a evaporating plate for a pestle: Result was a broken evaporating plate.....
2. There was no/little colour change through most of the fruits/ Vegetables. WE expected ALL of samples to actually change, but we believe that there was no reaction between the DCPIP and the Vitamin C, hence the colour change was probably just discolouration.
3. We think that the DCPIP solution was probably too condensed, another reason for the lack of colour changes. We are therefore changing the condensation to 1 gram to 200ml of water.
4. The fruit will also be left for more than a minute, instead about two and a half.