Is there salt in blood

No. Osmosis will cause the red blood cells to release all of their moisture, and at the same time keep all of the materials INSIDE the cell wall. That's where the color comes from. If you use fresh water, or salt free water, osmosis will attempt to balance the salinity between the inside and outside of the cell resulting in cell rupture, called lysis. Salt water does not dry up the blood, it just makes it easier to clean.