Why cook octopus with an onion?
I've been following all the rule books on how to cook fresh/thawed octopus, specifically to "frighten" the octopus before cooking. The "frightening" is a quick 10 second bath in the boiling water, repeated 3 times, which shrinks the arms. I know I have to put spices in the water where I cook the octopus, and perhaps some sea-salt. All that will help to tenderize the octopus.
Now the question is: Why is it recommended to add a whole onion, including the skin? Is there some reaction with the onion and the octopus while cooking?
Note: This is a wide spread recommendation on how to cook octopus in Portugal.
Best Answer
I would suspect for the same reason you often marinade steak or meats in onions.
According to the answer onions contain proteolytic enzymes which are natural tenderizers, by breaking down proteins into smaller polypeptides or single amino acids, common in natural processes like digestion.
From Wikipedia
A protease (also called a peptidase or proteinase) is an enzyme that catalyzes (increases the rate of) proteolysis, the breakdown of proteins into smaller polypeptides or single amino acids. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in many biological functions, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling.
It is easy to believe these would have on octopus flesh a similar effect that they have on other meats. Whether it is significant or not may be open to debate, some times old traditions tend to stick around even after being debunked as myths.
Keeping the skin on is probably just a practical consideration for preventing it from breaking into pieces and spreading all over, as well as easier removal.
Like other seasonings it probably also imparts some flavor, even if residual, which some people might find pleasant, adding to the advantages.
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What is the best method of cooking octopus?
The most basic way of cooking octopus is to simmer it in liquid. Fill a saucepan with salted water and bring to the boil. Add the octopus, reduce the heat immediately and simmer gently for 45\u201360 minutes. It's important that the water is turned down to a gentle simmer once the octopus is in the pan.How do you make octopus tender?
More research ensued and we found information that the addition of wine corks added to the cooking liquid ensured a more tender dish. Experts have argued about this method but most chefs and those who regularly prepare squid and octopus swear that there are enzymes in the corks that insure a more palatable dish.How Juicy To Cook OCTOPUS With Vegetables? A Very Tasty Recipe For Cooking Octopus
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