In total, there are 20 different amino acids of which a variety of different proteins can be composed. The body is able to produce most of the amino acids. However, 10 amino acids are essential, this means they have to be taken with the food. These are: leucine, lysine, valine, phenylaline, methionine, histidine, tryptophane, arginine, threonine, and isoleucine. Amino acids are produced in a fermentation process. Falling film evaporators for the concentration of fermentation broths are an essential component of the production plants.