Subject: Why does food coloring enter a potato in salt water?

We did an experiment on osmosis by putting a potato in fresh an salt water. We 
noticed that the potato in the salt water lost mass and concluded that water 
left the cells. the opposite was true for the fresh water potato, it gained 
mass. We predicted that if food coloring was added to the salt water and fresh 
water containers, the coloring would enter the fresh water potato and not enter 
the salt water. The opposite happened. The salt water potato absorbed the food 
coloring and the fresh water potato didn't. Could be because of diffusion but 
not sure. 

Re: Why does food coloring enter a potato in salt water?