There's a lot of mystery still about how salt enriches flavors of foods. Table salt is composed of sodium ions (Na+) and chloride ions (Cl-). Both the sodium ions and the chloride ions are needed to make food taste salty, because baking soda doesn't make food taste salty like table salt, and baking soda has sodium ions but not chloride ions. The negative ions in baking soda are bicarbonate (HCO_3-).

Two scientists think salt makes good flavors taste stronger and bad flavors taste less, but I don't think their experiments are very good.

Here's where they published their research and ideas:
"Salt enhances flavor by suppressing bitterness" (Nature, Volume 387, Issue 6633, pp. 563 (1997)

Thanks for your question - I like it. My son helped me find this answer for it. He knows a lot about food.

Saltiness is one of the four things that you can taste - together with sweetness, sourness, and bitterness. The other elements of flavor are for the most part actually smell (and to some extent texture). Smell is an extremely complicated thing and neurobiologists are still trying to unravel how it operates and why it works the way that it does.