What Are Salts in Chemistry?

When we think of the word “salt,” our brains often lead us to think of sodium chloride, the well-known “table salt.” But, to clarify what a “salt” really is, we need to recall some concepts of inorganic chemistry:
“Salt is a chemical compound formed, generally, by neutralization reactions (between acids and bases, forming salt and water). Compounds that, when dissolved in water, form cations (elements with a positive charge) and anions (elements with a negative charge), other than H+ and OH-, are considered salts.

Examples of salts used in food to enhance flavor include sodium chloride (table salt – NaCl), potassium chloride (KCl), monosodium glutamate (MSG), inosinate (IMP), and disodium guanylate (GMP).

Sodium chloride is a salt that has been used for a long time, considered a preservative, mainly because it prevents the growth of microorganisms, since it has the ability to reduce the water activity* of some foods such as canned vegetables, dairy products, meats, fish, and seafood. Another essential function of this product is the Sodium chloride enhances the flavor of food. When added, it promotes a salty taste. Upon contact with saliva, chlorine and sodium dissociate and enter taste cells through specific ion channels. After the sodium ion enters these cells, depolarization of the membranes occurs, meaning they become positively charged. This depolarization causes the membrane’s electrical potential to increase and activates the gustatory nerves, which send signals to the brain, thus producing the taste.

Nutritionally, the sodium ion has several functions, such as: transport of positive and negative electrical charges; maintenance of osmotic pressure; acid-base balance; regulation of intra- and extracellular fluids, acting in the maintenance of blood pressure; and nerve and muscle function.

Because sodium chloride has all these functions and is also low-cost, it is used by the food industry for preservation and to provide flavor, as the acceptance of salty taste is already part of the culture of many populations due to its historical use.

However, it was Recently, there has been a noticeable increase in sodium chloride consumption among the population, exceeding the recommendations of the World Health Organization (WHO), which establishes a daily intake of up to 5g of sodium chloride (or 2g of sodium). This recommendation was established because high concentrations of sodium ions can cause several health risks, such as excessive water loss, kidney failure, and diabetes insipidus (inappropriate secretion of antidiuretic hormone), which can lead to symptoms like confusion and muscle contractions. Frequent and high consumption of fats, sugar, and salt can increase the risk of chronic non-communicable diseases such as obesity, high blood pressure, diabetes, and heart disease.

Campaigns to Reduce Sodium Consumption
To prevent high sodium consumption in Brazil, the Ministry of Health conducts campaigns and offers nutritional guides to the population. Another action was established by the National Health Surveillance Agency (Anvisa) and the Brazilian Association of Food Industries (Abia), which made an agreement to reduce sodium concentrations in processed foods.

Some foods are already being launched with reduced sodium content. Other types of salts are also being used to help reduce sodium. One example is potassium chloride, which also provides a salty taste, but with less intensity. For this reason, it is often used in combination with sodium chloride. These are commercially called “low-sodium salt” or “light salt,” which, according to legislation, contain up to 50% less sodium than sodium chloride.

Other examples of salts are sea salt (“fleur de sel” – “flower of salt” in French), which is manually scraped from the surface of lakes. It can be coarse, fine, or flaky, white, pink, black, gray, or a combination of colors, depending on the types of minerals in its composition. This combination with other minerals can also slightly reduce the concentration of sodium ions in these products, but it is still predominant. There are also some salts that are mixed with spices, such as black, white, and pink peppercorns, cumin, oregano, thyme, or dried basil, which can add flavor to the dish.

Salts such as monosodium glutamate, disodium inosinate, and disodium guanylate have low sodium concentrations in their chemical composition: 12.3 g/100g, 11.7 g/100g, and 11.3 g/100g, respectively; while sodium chloride has 38.8 g of sodium per 100g of salt.

It is worth noting that the salts mentioned in the paragraph above provide umami flavor, not saltiness. The study published by Rosa et al. (2021) revealed that to reduce the amount of sodium in preparations such as rice and ground meat, with umami salts, it is recommended to replace half the amount of salt used in recipes with the ingredient. For example, for 500g of food: instead of including a teaspoon of salt in preparations, it is recommended to use half a teaspoon of salt and half a teaspoon of monosodium glutamate. In this way, it is possible to reduce the sodium content by 30% and 33% respectively.
We suggest alternatives to reduce sodium in meals through the diversity of salts that we can use. These diversifications of tastes and aromas are important and can provide us with good health combined with good taste.

* Water activity is a measure of the tendency of water to escape or fugacity from a solution relative to the tendency of pure water to escape at a specific temperature.