Chicken marinade with soy sauce - have I done something wrong? I have made a chicken marinade with soy sauce, olive oil, dry herbs and spices.
I put it to marinate for 3-4 hours (like I mostly do), but I couldn't cook it that night so I left the chicken in the marinade over night.
The chicken was left to marinate in the refrigerator, in a sealed ziplock bag.
The next day the chicken had some brown dry parts (almost like a burn). I expected it to be brown, but the dry parts were looking awful. I threw away the chicken at that time because I thought it wasn't safe to eat.
Have I done something wrong? Is it safe to marinate in soy sauce for more than a few hours? Could I have prepared that chicken without any worries?
Soy sauce is pretty salty. It sounds like a great deal of water diffused out of your chicken and into the marinade, which significantly changed the texture of the meat.

It's not uncommon to do something like this on purpose. When you make gravlax, for example, you cover a piece of salmon with quite a bit of salt and refrigerate it for a day or two. The salt draws out a lot of moisture, causing the fish to firm up considerably. Even though your soy sauce marinade was liquid, it still had a much higher salt concentration (or to think of it another way, a much lower water concentration) than the chicken, and would have had the same effect.