If you eat salmon a lot, then you might notice from time to time that there's a gooey white substance that often appears along the edges. There are all kinds of myths about what this stuff really is, but if you want some clarity, then you've come to the right place.
It's actually a protein known as albumin, and when salmon becomes cooked, the heat and pressure forces the albumin from the inside of the salmon to bleed out to the surface. It's normally transparent, but when it reaches the surface, the effects of cooking turn it white, similarly to egg whites.
Albumin is safe to eat, but the appearance of the goop is slightly off-putting for many. Typically, salmon-eaters will scrape it away from the block of fish for their own self-assurance, but some go ahead and heat it with the fish anyways.
By brining your salmon before cooking it, you can minimize the effects of albumin after cooking salmon, but no matter what, albumin is a byproduct of cooking the fish and will almost always occur, even if not so much after the brining process.