Proteins are the basis for building the body's own proteins and are thus an important component of the energy supply. They consist of amino acids, which can be divided into essential, semi-essential and non-essential.
While the human body produces non-essential amino acids itself, semi-essential ones cannot be synthesized in sufficient quantities in certain life situations, such as pregnancy, illness or growth. These amino acids include cysteine, tyrosine, histidine or arginine. Essential amino acids cannot be produced and must therefore be supplied through the diet. These include phenylalanine, threonine, tryptophan, valine, isoleucine, leucine, lysine and methionine.
Biological value of proteins
The biological value is considered the best-known method for estimating the quality of proteins in foods. This measure tells how much of an ingested dietary protein can be converted into the body's own protein.
The amino acids are considered an important criterion here. The higher the content of essential amino acids, the higher the quality of the protein. However, if essential amino acids are present in too low a quantity, they become limiting amino acids that limit the quality of the protein.
Here are some examples of biological values (reference value: whole egg=100).
| Proteine source | Biological value | Limiting AS |
| Lupine | 60 | |
| Peanuts | 52 | |
| Hemp | 61 | |
| Peas | 50-60 | |
| Quinoa | 83 | |
| Soy | 81-86 | Methionine |
| Corn | 50-60 | |
| Rice | 66-83 | Lysine, Tryptophan |
| Wheat | 53 | Lysine, Threonine |
It is interesting to note that several protein sources can be combined, deficiencies can be compensated for and thus higher biological values can be achieved.