Why does animal fat stick to leaf of lettuce?

[curiousgorge]

I was making stew just the other day, and being a novice at it, ended up with globs of fat in my stew. Quick search through the internet found that skimming the surface with a leaf of lettuce would help, as fat would stick to the leaf.

 

Tried it, and it worked... not too well, but enough to get by. Just curious as to what it is about lettuce leaf that lends to it such property.

 

-CGorge