Pasta should be cooled down before adding mayonnaise as adding mayonnaise to hot pasta can cause the mayonnaise to become oiling and separate and result in a less appealing flavor and texture.
Mayonnaise is an emulsion of egg yolks and oil and heat can disrupt the emulsion of the mayonnaise.
For tuna pasta salad you should let pasta cool down before adding the tuna.
Allowing the pasta to cool down before adding tuna to tuna pasta salad prevents the pasta from getting mushy and helps the tuna pasta salad maintain it's desired texture.
If making pasta dishes that are served hot like a casserole or Tuna Pasta that is served hot you should add the tuna into the pasta while it cooks or while it's still hot.
To make Italian tuna pasta start by cooking the spaghetti until it's al dente.
Then as the pasta is cooking, prepare the sauce by heating some olive oil in a skillet and sauteing of some chopped onions and anchovy fillet if using anchovy fillet.
Then add in some crushed red pepper and garlic, and stir in crushed tomatoes.
Next reduce the heat and add the capers and canned tuna, breaking up any large pieces.
After the pasta is cooked then you can drain the spaghetti and toss the spaghetti with some tuna sauce.
Then garnish it with some fresh herbs before serving or eating.
You can also add a small amount of starchy pasta water to the sauce which can help it coat the pasta better.
You can also enhance the flavor with some ingredients like chopped olives, fresh herbs, a squeeze of lemon juice or lemon zest.
If you want added texture you can top the dish with some garlic and fried breadcrumbs.
A simpler version of Italian tuna pasta is combing cooked pasta with tuna packed in olive oil, olives and a drizzle of olive oil.
The ingredients for Italian tuna pasta include.
Chopped fresh parsley or basil to garnish.
Canned tuna in olive oil.
Capers.
Crushed tomatoes.
Anchovy fillet which is optional.
Crushed red pepper flakes.
Chopped onion and minced garlic.
Olive oil.
And spaghetti.