Proteins are made up of amino acids and different proteins contain different proportions of the various amino acids.

There are in all 23 amino acids in food proteins. Out of these, there are 10 that the human body cannot synthesize: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophane and valine. These are, therefore, called essential amino acids.
The body must be supplied with the requisite amounts of these amino acids through food. The rest of the amino acids can be synthesized by the body from these.

When I got to Florida without my blender or juicer I bought a couple of bottles of goodies. One was Perfectly Protein Vanilla Chai Tea with Soy Protein by a company which has been around since 1915 - Bolthouse Farms.

Bolthouse Farms is a family farm in the San Joaquin Valley of California. In 1915 the family started vegetable farming in Michigan. Now, on their fourth generation of farmers. They supply close to 80% of the fresh carrots in the United States.