The oil is the triacylglycerol.
Yes, lecithin in the egg yolk is the emulsifier that emulsifies oil and vinegar/lemon juice to make a mayonnaise emulsion.
It is only the egg yolk that contains lecithin which is the emulsifier that makes it possible to create the oil emulsion. Mayonnaise usually also contains vinegar or lemon juice (which are mostly water) to enhance the flavor. The egg white is also mostly water and it is pretty easy to successfully make "whole egg" mayonnaise. Perhaps, the white is traditionally left out because it has its own valuable uses in cooking other things.
Lecithin is good for the GI tract. It's consists of phospholipids, which are important components of the intestinal mucus layer. That is why lecithin is used to cure ulcerative colitis.
One can add herbs, garlic or extra mustard.
Egg yolk contains lecithin which is an emulsifier or surfactant which acts as a dispersal agentfor fat in water. I don't get the chemistry, but then, I don't have to get it
double
To improve the emulsification process
double
Two pouches of tuna and two ounces of mayonnaise would make a double batch.
Eggs, vinegar and oil.
this will give a more delicate flavored to the mayo
An emulsion is when the water and the oil in a food are mixed together, for example in mayonnaise. An emulsion needs an emulsifier to hold the oil and the water together. Eggs or soy lecithin are examples of emulsifiers.