These days, there is much concern on our consumption of food drink, we're told we do not intake the required daily level of fruit and veg, many manufactures claim to provide excellent levels of nutrients, This experiment will be carried out to see whether the vitamin c levels claimed by manufacturers are actually present in the drinks, this will be done by experimenting various drinks using blue DCPIP solution.
The quantity of vitamin C in food and drink can be determined using a simple colour test. Vitamin C decolourises the blue dye DCPIP (dichlorophenolindolphenol). Vitamin C is an antioxidant and reduces the DCPIP. DCPIP changes from blue to colourless (or slightly pink) as it becomes reduced.
Is High vitamin C all it claims to be?
Fruits have high levels of vitamin C therefore fruit juice, in particular orange will require the least volume to decolourise DCPIP as Orange juice has the most Vitamin C.
The nature of this experiment is unlikely to have any ethical issues, the aim of the results is increase understanding of our diet and nutrition levels.
Independent: The type of juice.
Dependant: The Vit C content/volume (cm³) of DCPIP required for decolourisation.
Variables which may affect the result:
o The drinks were kept in the fridge, at 4 degrees ºC, then at room temperature for 20 mins.
o The Best Before date was unchecked, and if old, then it may have caused bacteria to grow and consume the vitamin C and other nutrients.
o Concentration of DCPIP (1%)
o Volume of DCPIP (1cm³)
The independent variable will be controlled so the results will be reliable and valid and their impact will be minimised in the experiment. I will also run a control experiment with distilled water, to show that it is the Vitamin C that is decolourising the DCPIP and nothing else. (Water contains 0% of Vit C)...