when boiling лосось that was frozen, what is a large amount of white foam indicate?

I have this same problem when I boil chicken. I believe this is blood from the meat, but because it is emersed in water that is boiling, Ты don't see the red blood that would have come out of the meat when Ты fry, bake, или grill it, but the blood cooks as soon as it come out of the meat in the water and looks white. I just scoop it off the вверх with a spoon(this is called "skimming the top") and wash it down the sink. Then the rest of the liquid in your pot will be almost be clear.