The citric acid in your tomato cans is insurance to cover the cost cutting and arguably lower standards without getting customers sick.
I'm american, but have traveled. Factory conditions in North America are not the same as in Europe. They are dirtier and more "cost efficient". Therefore american companies will take extra measures to ensure safety that ...
Citric acid is added when the PH of the overall product is too high. Most of the time a product with pure tomatoes doesn't need any help with PH as the tomatoes should be acidic enough, when you see citric acid added you will usually see water added as well in some form. Water is added to bulk up the product and make it cheaper, some companies add tomato ...
E330 - commonly named on a labels as citric acid to not scare consumers - is an antioxidant. In tomato sauce I would say it's used to stop it from browning (and as a mild conservative).
The difference beetwen European and North American is just a shelf life of sauce. Both on shelf in store and at home.
As other have said, you can absolutely add tomatoes, but then you will be making tomato soup, not chicken soup. (There aren't many soups you can add tomatoes to that won't just become tomato soup.)
Saute two large yellow onions in a bit of oil.
Add 3 units (+) of chopped or crushed garlic. (From a jar OK but not as good.)
Add 3-4 stalks chopped ...
A few questions to consider:
Were you following a recipe that used an additional acid (like citric acid or lemon juice) in addition to tomatoes and peppers?
Does your recipe include significant amounts of garlic or onion?
Does your recipe specifically call for water bath canning?
How many years old is your recipe?
The reason I ask these questions is that ...