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CHEMISTRY, M3 EQ-Bank 4 MC

The fruits of the cycad Macrozamia, are known to be highly toxic for consumption.

Which of the following methods conducted by Indigenous peoples is most effective in removing toxins from this cycad?

  1. Letting the seeds mature before consuming them.
  2. Removing the individual seeds from the fruit before cooking them in a fire.
  3. Cooking the seeds with fire before leaching them out in running water overnight.
  4. Removing the individual seeds from the fruit and baking them in the sun.
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\(C\)

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→ Cooking of the seeds in fire helps to break down the toxins within the seeds.

→ The toxins within the seeds are soluble compounds and so the leaching process helps eliminate any remaining harmful substances as the toxins are dissolved and diffused into the water and then washed away.

\(\Rightarrow C\)

CHEMISTRY, M3 EQ-Bank 1 MC

For centuries, Indigenous Australians have used chemical processes to detoxify certain foods. The seeds of the nardoo fern (Marsilea) were a traditional food source, but they contain harmful toxins. To safely consume the seeds, they were first ground into a paste and soaked in water for several days.

Soaking the nardoo seeds aids in detoxification by:

  1. Causing the water to neutralise the harmful substances.
  2. Altering the chemical structure of the toxins through grinding.
  3. Allowing the water to remove the toxins from the paste.
  4. Increasing the temperature to speed up the breakdown of toxins.
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\(C\)

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→ Water removes the toxins from nardoo fern seeds during the leaching process because the toxic substance is water-soluble, meaning they can dissolve in water.

→ When the seeds are soaked, the toxins dissolve and diffuse into the surrounding water. By changing or draining the water, the dissolved toxins are effectively removed from the food.

→ This process relies on the solubility of the toxins, and repeated soaking ensures that a significant amount of the harmful compounds is washed away, leaving the food safe for consumption.

\(\Rightarrow C\)