Impossible burger is made by a company that has used soy bean leghemoglobin found in root nodules of soybean plan to add to their burger and enhance taste. Now, this leghemoglobin in similar to animal hemoglobin and releases iron just like a real hemoglobin molecule and perhaps that extra something adds to the taste of the plant-protein burger.
If hemoglobin adds taste then there is another source of that in sea food. Clams. These normally do have gills and they get their oxygen by filtering water and accessing the dissolved oxygen in water.
Let food be thy medicine and medicine be thy food
Hippocrates
Blood clams are bite size cockles that are full of hemoglobin that is the same molecule in human blood that is used to transfer oxygen. Hemoglobin does exactly the same thing in those clams, it helps them live in places that do not have much oxygen. However, clams also filter water and so they can become a source of pollutants or bacteria and hence can be dangerous to eat. But, they have been known to be a delicacy and may have a cleaner and crisper texture than the regular clams. So, curious if it is their hemoglobin that gives it that extra flavor like an impossible burger?
Note: There has been research on the origin of clam hemoglobin that makes informative reading: https://pmc.ncbi.nlm.nih.gov/articles/PMC8136487/
