What does it mean trans-free margarine?
This trans is obviously shortened from sth.
Thank you

This means- A class of transferases(Any of various enzymes that move a chemical group from one compound to another compound) that catalyze transamination (that transfer an amino group from an amino acid to another compound)...

"trans-free" is "trans fatty acid free" or "trans fat free" or "free of trans fats and trans fatty acids". This is unusual for magarine, which is usually full of trans fat.

It has nothing to do with enzymes or transamination (the transfer of an ammonium radical - something not contained in fats), and everything to do with the shape of the fat molecule. When carbon atoms chain together, they usually take the "cis" configuration:

/\/\/\ This is the pattern found in "cis" fats / fatty acids.

The "trans" configuration of carbon chains does not alternate in the same pattern:

\_/\_/ This is the pattern found in "trans" fats / fatty acids. (My understanding of it is that no living thing produces such a pattern. It has to be produced artificially.)

"cis" basically means "on this side", "on the same side" (as where I stand); "trans" basically means "on the other side" (from where I stand). So if you are standing before a mountain, you can see the "cis" side, but you would have to climb over it to see the "trans" side. Likewise, in the cis fatty acids the turns in the chain constantly return back to the "same side" of the chain. In the trans fatty acids the chain may stay on the "other side" for some part of its length.

"Trans fats are produced through hydrogenation, a chemical process by which hydrogen is added to unsaturated fatty acids. Hydrogenation converts the unsaturated bonds in the oil into saturated bonds, creating a solid, spreadable fat with increased shelf life. Hydrogenation gets rid of some double bonds, but incompletely transforms others. These double bonds are transformed from the natural “cis” configuration to the “trans” configuration. Research indicates that eating trans fats is associated with an increased risk for heart disease."