I heard on the radio today, NPR’s Talk of the Nation, and a guest cook told the listeners to "put their turkey in a salt base (1 cup of salt per gallon of water) and this will help keep the juices inside the turkey and will make it even juicer.
Question: Wouldn’t the process of osmosis leave the turkey with less juice inside?
Turkeys (and pretty much every other meat) contains salt water in it already. So nothing is getting taken out.
Brining, as described in Harold McGee’s On Food and Cooking (page 155):
“Brining has two initial effects. First salt disrupts the structure of the muscle filaments. A 3% salt solution (Scandinavian bring was done at 3 to 6% salt concentrations) dissolves parts of the protein structure that supports the contracting filaments, and a 5.5% solution partly dissolves the filaments themselves. Second the interaction of the salt and proteins result in a greater water-holding capacity in the muscle cells, which then absorb water from the brine (the inward movement of salt water and disruptions of the muscle filaments into the meat also increase its absorption of aromatic molecules from any herbs and spices in the brine). The meat’s weight increases by 10% or more. When cooked, the meat still loses around 20% of its weight in moisture, but this loss is counterbalanced by the brine absorbed, so the moisture loss is effectively cut in half. In addition the dissolved protein filaments can’t coagulate into normally dense aggegates, so the cooked meat seems more tender. Because the brine works its way in from the outside, it has its earliest and strongest effects on the meat regions most likely to be overcooked, so even a brief, incomplete soaking can make a difference.”
As waterman cites (great name for this post by the way) - what may be happening is that salt helps break down the proteins into smaller fragments, which increase the osmotic drive to pull water inside the meat. Some more thoughts on it here in the good Cooking for Engineers site http://www.cookingforengineers.com/article.php?id=70