Add different titles instead of "quantity"

Hi
I want to add two titles instead of “quantity” (danish: antal) for each different category. (Link: http://prntscr.com/7u1hlu)
I have a category called “bland-selv-slik” and in that category I want the “Pr. slik-ske (20g)” instead of “Antal” and in the other categories I just want to have “Antal”
 
How can I apply that?