I have my doubts about this, and also whether it is relevant that a pressure differential can increase the rate of osmosis. If, as the author contends, meat ca

I have my doubts about this, and also whether it is relevant that a pressure differential can increase the rate of osmosis. If, as the author contends, meat can be regarded as a water-saturated matrix of proteins [1], then the pressure inside the meat will rise to match the external pressure. The only way for a pressure differential to form would be if the matrix formed a very rigid shell (even a slight flexibility would allow the pressure to equalize), but it does not. Furthermore, because water is almost incompressible, this occurs without any appreciable change in volume. The author suggests that if the matrix compresses, then that will expel water, but this will only be the case if the voids in the matrix become smaller. It's more likely, I think, that the only change would be that the walls of the voids will become thinner, as the water inside the voids can follow the pressure increase without changing appreciably in volume: in effect, the water inside the voids supports them against the pressure outside. All of this assumes the pressure is being applied equally in all directions, which is the case if you are applying the pressure to the marinade, rather than squeezing the meat in one direction. [1] Or a cellulose matrix in the case of vegetables.