Can Different Temperatures Affect the Cell Membrane of a Beetroot?

Biological pigments, also known as pigments or biochromes are substances produced by living organisms that have a colour resulting from the selective colour absorption. The pigments in beetroot are betalain pigments; they are located in the vacuole of the cell. They are named after the Beet family of plants, but are also found in fungi. In the petals they are thought to attract pollinating insects and may be present in seeds/fruits to encourage birds to eat them and so spreading around the seeds.

When a beetroot in heated, it tampers with the cell membranes. A membrane is made of a phospholipid bilayer. These are formed because the phospholipids that make it up have a hydrophilic (‘water loving’) head and a hydrophobic (‘water hating’) tail. The tails pack together, exposing only the heads to the water. This is the phospholipid bilayer. The beetroot pigment is used commercially as food dye. It changes colour when heated so can only be used in ice-cream, sweets and other confectionary, but it is both cheap and has no known allergic side-effects.

Aim

To investigate whether different temperatures can damage and denature the plasma cell surface membrane of beetroot cells. This would then release the beetroot pigments out of the vacuole which causes the leakage of the purplish liquid.

Hypothesis

Beetroot in hotter water will release its pigments more than beetroot in cooler water. The hotter water should break more vacuoles containing the pigments which will make the water appear to be more purple. Meanwhile the colder water will still have pigments throughout the water, and therefore will be scarcer.

Materials

x6 Test Tube

x1 Chopping Board

x1 Serrated Knife

x1 Corer

x6 Skewers

x2 Beetroot

x3 Test Tube Rack

x1 Wooden Test Tube Holders

x1 Bunsen Burner

x1 Match Box

x1 Cork Mat

Method

Use the corer to get equal cylindrical pieces of beetroot

Cut pieces to same size if they are unequal

Skewer the beetroot through the middle

Rinse the skewers of beetroot

Fill the test tubes to half way with water

Place beetroot skewers into test tube and test tubes into test tube holder.

Cold

Put in fridge and freezer

Remove after chosen time, and record your observations.

Hot

Put over a hot flame and a purple flame

Remove after chosen time, and record your observations

Results

Discussion

Beetroot in hotter water will release its pigments more than beetroot in cooler water. The hotter water should break more vacuoles containing the pigments which will make the water appear to be more purple. Meanwhile the colder water will still have pigments throughout the water, and therefore will be scarcer. The hypothesis was supported by the results as the beetroot in the hotter water did release more pigments than the beetroot in the colder water.

Some problems that came to attention were the exact sizes of the beetroot pieces could not be made the exact same size. Even though cutting them side by side of each other did make them look similar, the sizes were off still. The experiment as brought sight to what can happen when a fruit or vegetable or flower is heated in water will do. The water colouring process will accelerate more than twice as fast and that could provide big opportunities in some companies. A flaw in the experimental design was that attention wasn’t given to the material of test tubes that were used. A glass test tube was used for the beetroot that was frozen in the freezer; while in fact a plastic test tube should have been used because the glass test tube could not flex to the expansion of the water in the test tube and so resulting it to crack.

  Conclusion

In conclusion, the hypothesis was supported as the beetroot’s pigments were release more in the hot water more than the cold water did. The hotter water made the beetroot cell vacuoles to burst, releasing the pigments, thus colouring the water.