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Why does the colour leak out of a cooked beetroot?

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Why does the colour leak out of a cooked beetroot? Introduction I predict that as the temperature increases, more betalains pigments will leak out of the beetroot, causing the water to become darker. The rise in temperature will cause the membranes to become more permeable. Then as the temperature increases, the proteins in the membrane start to wobble. This then causes the hydrogen bonds holding their shape to break. This happens in channel protein and due to this the cell membrane structure cannot control what enters and leaves the membrane, causing the betalains to leak out. I predict that between 20�C and 60�C the proteins will start to denature at a faster rate. Planning The procedures used in the method, will generate appropriate measurements that I can test, because the measurements are very precise and accurate. The instructions are well explained and easy to follow ensuring that measurements and temperatures are also precise. The experiment is valid enough to repeat the experiment to ensure reliability. The thermometer is suitable because it will give accurate readings of temperature. The pipettes are also accurate because it will measure out exactly 2cm3 and 5cm3. ...read more.


The random errors may be reading the volumes, or not precisely measuring out the volumes. Carelessness, like not concentrating on times that is meant to use during the experiment (30 minutes). Or likewise, not taking care when measuring the temperature of substances, it could go over the temperature needed. The only alterations I would suggest would be to repeat the experiment 2 or 3 times to get an average. Risk Assessment * When cutting the beetroot into 1cm sections, take care when using the knife, these may be very sharp. * The temperature of the water will be very hot in some of the water baths; do not let it get on the skin, as this will scold the skin. Be careful not to bump into the water baths, this could spill the water, cause injury or cause people to slip and get injured. * When transferring the liquids from different boiling tube, use tongs or heatproof mats to prevent scolding of the hands. * Carelessness could cause the glass to break, causing an injury. * Ensure test tubes are kept in test tube racks, and keep all glass apparatus in the middle of the worktop. ...read more.


Anthocyanin is a family of pigments that give flowers, fruits and leaves of some plants their red or blue coloring. This has been ?shown by a steady increase in betalains which leaked out of plant cells, which was then measured by the colorimeter light absorbance, as the temperature increased. By analyzing the results, denaturing occurs between 400C - 500C. The breakdown of the lipids which make up the membrane which causes 'holes' to appear in the membrane, allows fluids to pass out freely, but ?when the temperatures begins to get higher, the proteins in the ?cells begin to break down as well which blocks some of the holes and ?therefore slowing down the release of anthocyanin. It is safe to say that the results have been repeated ?reliably however it still would have been beneficial to have repeated ?the experiment more times to make certain that the results were not ?gained through chance or by an external factor. Distilled water was used, which is the clearest possible liquid, meant that even the slightest deviation in colour ?could be detected by the colorimeter. Rianne Malcolm 12H ...read more.

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