Not only is salt one of the five tastes, it also impacts others. Salt reduces bitterness. It enhances aromas, which play a big role in our perception of flavors aside from just taste. It can also add textures.
Salt performs other functions that don’t have to do with flavor. When added to boiling water, it keeps pasta from sticking to itself by “reducing the gelatin-like layer that forms on the surface of pasta as it cooks,” Nik Sharma writes in “The Flavor Equation.” For blanching vegetables, “Properly seasoned cooking water encourages food to retain its nutrients,” Samin Nosrat says in “Salt, Fat, Acid, Heat.”
What else can salt do? It can ward off rubbery scrambled eggs by buffering the proteins from bonding too tightly and squeezing out water. In brining, whether wet or dry, salt helps meat retain moisture; in the case of a dry-brined turkey or chicken, it can contribute to crisp, golden skin.
Salt has long been valued as a preservative and an important element in fermented foods. It’s also key in baking bread and sweets; see below.