Before we answer the question of why we add salt to foods, we first need to clarify the difference between taste and flavor. While we often use the terms interchangeably, they actually refer to two different things.
Technically, taste is part of the five major senses, and consists of the five basic qualities, namely sweet, sour, salty, bitter, and savory (also called umami). A quick check to see whether you are experiencing ‘taste’ or ‘flavor’ is to pinch your nose while tasting foods. With your nose pinched, you will be able to sense any of the five basic tastes, thanks to the taste receptors on your tongue. Once you open your nose, you will then experience additional sensations called flavor. There are a few reasons why we use salt in foods.
When we add salt to foods, the taste receptors on our tongues perceive saltiness, which in turn, enhances the other flavors in the foods we eat. It also balances out other tastes like sweet, sour, and bitter. While excessive amounts of salt can taste bitter, when you add just the right amount, it actually suppresses the perception of bitterness.
Chemically, salt denatures proteins, which also contribute to better flavor. This explains why salt and meat are a perfect match! Salt perception may be one of the five basic tastes, but it also contributes the way we perceive flavor. This is because it stimulates our olfactory receptors, improving our sense of smell.
Salt has been used for thousands of years to preserve meat, fish, and dairy products. And even today we still use it in this way. Salt (dry salt or from a brine) draws out the moisture from foods. This dehydrates the bacterial cells already present, and prevents the future growth of bacteria and molds.
Besides taste and preservation, salt has other functional roles. When salt is added to processed meats, it helps to extract ‘myofibrillar proteins’ which then act as a binding agent between meat and fat. It also improves the water binding capacity (in other words, reduces water loss during cooking), which makes the meat product more tender and palatable.
Salt also has an effect on the texture of foods. In bread, it helps to strengthen gluten, allowing for the bread to rise without tearing.
Salt even plays a major role in the color of processed meats (such as bacon and hotdogs). Food manufacturers use salt together with sugar and nitrites to produce the bright color that we associate with these meat products. Additionally, when added to bread, salt assists in the breakdown of sugar, which helps with the development of a golden-brown crust.