Yes, salt can reduce the perception of sweetness in sauces by enhancing other flavors and creating a more balanced taste profile. It doesn't eliminate the sugar, but it masks the intensity of the sweetness.
Salt and sugar interact on our taste buds in a complex way. Salt enhances our perception of other flavors, including savory and umami notes. When a sauce is overly sweet, adding a pinch of salt doesn't actually remove the sugar molecules. Instead, it stimulates different taste receptors, making the sweetness less dominant. This creates a more balanced and complex flavor profile where the sweetness is still present but not overwhelming. The salt essentially 'lifts' the other flavors, preventing the sweetness from being the only thing you taste. Think of it like adjusting the volume on different instruments in an orchestra; salt can turn down the 'sweetness' volume while turning up the 'savory' volume. The key is to add salt gradually and taste as you go, as too much salt can obviously ruin the sauce.
When adjusting sweetness with salt, use a fine-grained salt like table salt or sea salt. Coarse salt may not dissolve evenly and can create pockets of saltiness, leading to an uneven flavor.