Why is my biltong not pink as it is in your pictures?

As soon as the surface of the biltong is open to the air, oxidation occurs.  This alters the pink to turn the biltong brown over time.  It does not change the tenderness, texture or flavour.  It’s just a natural reaction to the air.  If you want to see your biltong pink, buy it as a stick, in the same form that it would come out of the dryer, you can then slice it when you want, and the pinkness will still be there!