EDTA has poor solubility until you add a bunch of NaOH

That is exactly how you get disodium salt of EDTA AKA Trilon B AKA E386 food additive from EDTA.

That interesting salt prevent appearence of metal compositions that make apples become brown in air in apple juice or colouring tin can contents grey after long contact with metal.

Trilon B does not prevent meat going grey after thermal processing. It is sodium nitrite that is used to prevent that.

You could mix that things in case of canned ham, like SPAM, where both substances added to product. Sodium nitrite added to prevent meat become grey during processing and Trilon B is added to prevent ham miscolouring from walls of tin can.

EDTA has poor solubility until you add a bunch of NaOH

That is exactly how you get disodium salt of EDTA AKA Trilon B AKA E386 food additive from EDTA.

That interesting salt prevent appearence of metal compositions that make apples become brown in air or colouring tin can contents grey after long contact with metal.