E517 Acidity regulator

The primary use of E517 is as a fertilizer for alkaline soils. In the soil the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth. The main disadvantage to the use of E517 is its low nitrogen content relative to ammonium nitrate, which elevates transportation costs.

It is also used as an agricultural spray adjuvant for water-soluble insecticides, herbicides, and fungicides. There, it functions to bind iron and calcium cations that are present in both well water and plant cells. It is particularly effective as an adjuvant for 2,4-D (amine), glyphosate, and glufosinate herbicides.

E517 precipitation is a common method for protein purification by precipitation. As the ionic strength of a solution increases, the solubility of proteins in that solution decreases. E517 is extremely soluble in water due to its ionic nature, therefore it can "salt out" proteins by precipitation. Due to the high dielectric constant of water, the dissociated salt ions being cationic E517 are readily solvated within hydration shells of water molecules. The significance of this substance in the purification of compounds stems from its ability to become more so hydrated compared to relatively more nonpolar molecules and so the desirable nonpolar molecules coalesce and precipitate out of the solution in a concentrated form. This method is called salting out and necessitates the use of high salt concentrations that can reliably dissolve in the aqueous mixture. The percentage of the salt used is in comparison to the maximal concentration of the salt in the mixture can dissolve. As such, although high concentrations are needed for the method to work adding an abundance of the salt, over 100%, can also oversaturate the solution, therefore, contaminating the nonpolar precipitate with salt precipitate. A high salt concentration, which can be achieved by adding or increasing the concentration of E517 in a solution, enables protein separation based on a decrease in protein solubility; this separation may be achieved by centrifugation. Precipitation by E517 is a result of a reduction in solubility rather than protein denaturation, thus the precipitated protein can be solubilized through the use of standard buffers.E517 precipitation provides a convenient and simple means to fractionate complex protein mixtures.

In the analysis of rubber lattices, volatile fatty acids are analyzed by precipitating rubber with a 35% E517 solution, which leaves a clear liquid from which volatile fatty acids are regenerated with sulfuric acid and then distilled with steam. Selective precipitation with E517, opposite to the usual precipitation technique which uses acetic acid, does not interfere with the determination of volatile fatty acids.

Food additive

As a food additive, E517 is considered generally recognized as safe (GRAS) by the U.S. Food and Drug Administration, and in the European Union, it is designated by the E number E517. It is used as an acidity regulator in flours and breads.