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The warm weather is perfect for a cool meal! Ceviche (suh-VEE-chay) is a popular dish from Central and South America that relies on lime juice to “cook” seafood without any heat.

You will need

  • 150 grams sashimi grade fish (can be kingfish, salmon, tuna, trevally, or any soft-textured fish)
  • 2 limes
  • ¼ red onion
  • ½ jalapeño (optional)
  • 1 garlic clove
  • ¼ cup fresh coriander
  • ½ cup cherry tomatoes
  • 1 tablespoon extra-virgin olive oil
  • ½ avocado
  • Salt
  • Pepper
  • Corn chips
  • Juicer
  • Bowl
  • Knife
  • Cutting boards
  • Refrigerator

Safety

You’ll be handling vegetables and raw meat so make sure you wash your hands and use clean equipment. You’ll also need to use a sharp knife so ask an adult to help you cook!

food safety hazard icon

What to do

  1. Make sure you can source some sashimi grade fish for food safety reasons. Try asking the fish counter at your local supermarket or IGA. You can also buy sashimi from take-away sushi restaurants.

  2. Wash your hands with soap and water.

  3. Juice your limes into a large bowl. They should make about ¼ cup juice.

    Squeezing the juice of a lime into a bowl using a hand squeezer.
  4. Ask an adult to help you chop up your vegetables: dice the red onion, dice the jalapeño, dice the garlic, chop the coriander leaves, and quarter your cherry tomatoes. Put them all in the bowl, with some salt and pepper.

    Chopping board with three piles of diced vegetables.
  5. On a separate cutting board, ask an adult to help you chop up your fish into 1.5 cm cubes. What colour are the cubes of fish?

    Chop the salmon into cubes.
  6. Add your fish and olive oil to the bowl. Give it a good stir!

  7. Cover the bowl with a lid or cling wrap and then put it in the refrigerator for 30 minutes.

    Covered bowl in the fridge.
  8. After 30 minutes, check on your ceviche – has the colour of the fish changed? Give the ceviche a quick stir and then leave it in the refrigerator for another 30 minutes.

  9. When your timer goes off, chop your avocado into small chunks, on your vegetable chopping board.

  10. Take your ceviche out of the refrigerator – what colour is the fish now?

    Salmon mixture in a bowl.
  11. Add the avocado and stir. Give it a taste and add more salt and pepper if you want.

    Adding chopped avocado to the salmon mixture in the bowl..
  12. Open a bag of corn chips and use them to scoop up the ceviche! Buen provecho!

  13. Eat your ceviche on the same day you made it. It doesn’t keep well as too much time in the lime juice makes the seafood go tough!

    Bowl of Ceviche, some on a cracker ready to eat.

What’s happening?

Would you ever eat raw meat? Maybe you’ve eaten fish sushi or steak tartare … but most of time we use heat to cook our meat before we eat it.

Meat is mostly made of proteins, and each protein is made of a long chain of building blocks called amino acids. The 3D shape of each protein is very important to how it works. But this 3D shape is held together by weak bonds between the amino acids. It’s a bit like origami – and scientists even call it “protein folding” when talking about how a protein gets its 3D shape.

Heat adds a lot of energy to food. So as you cook meat, that energy breaks the weak bonds between the amino acids. As a result, the protein unravels, and the 3D shape is lost. Imagine an awesome origami dragon being completely unfolded into a piece of creased paper. Scientists call this process “denaturing”.

But heat isn’t the only way to denature a protein. As you discovered with your ceviche, the acid in the lime juice can also destroy the weak bonds holding proteins together. And as the protein becomes misshapen, it changes colour and texture. What changes did you observe as your ceviche cooked? Did it remind you of seafood cooked with heat?

Buen provecho!

“Buen provecho” is Spanish for “enjoy your meal” and it’s a polite thing to say before tucking in, especially in Latin America*. Ceviche also comes from Latin America! It probably originally came from Peru. But this recipe is more like the avocado-filled ceviche of Mexico.

Citrus fruits came to Latin America only recently, with the arrival of Europeans in the late 1400’s. But archaeologists have found evidence that suggests Peruvians were making ceviche with acidic chilli peppers and seaweed, possibly for thousands of years!

*Latin America includes the Spanish-, French- and Portuguese-speaking countries in Central and South America, Mexico and most Caribbean islands.

Did you know?

Did you know that cooking is way is older than our species? Our species, Homo sapiens, emerged about 300,000 years ago. Archaeologists think that our ancestors could have been cooking 2,000,000 years ago!

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