Ryan Ardoin, Jose Alonso, Pitchayapat Chonpracha and Witoon Prinyawiwatkul
Salt makes our food taste good, but excessive sodium intake, most of which is in the form of table salt (sodium chloride), is a major contributor to high blood pressure and strokes.
In the U.S., the average daily sodium intake is more than 3,400 milligrams (equivalent to 8.5 grams of salt), while the recommended intake is less than 2,300 milligrams sodium or 5.8 grams of salt per day, according to the U.S. Department of Agriculture. The salt we add to our food at the dinner table is not the problem. Rather, it is the “hidden” salt that is already in the foods we buy at the grocery store or eat in restaurants. Because of this, sodium has been called the “silent killer.” More than 40% comes from 10 types of foods, the top five being bread and rolls, cold cuts and cured meats, pizza, fresh and processed poultry, and soups.
LSU AgCenter researchers have been testing strategies for reducing sodium, but removing salt from food is not as simple as it may seem. Salt is a natural flavor enhancer and is the most-used food additive in the world. Perhaps most important, consumers have come to expect the salty taste associated with their favorite foods. So how can food companies make low-sodium products that people will still want to eat? Researchers in the AgCenter Sensory Services Lab use sensory science as a tool to explore answers to this question, using chemical, cognitive and food structure modification approaches to reduce sodium in foods.
One strategy, based on a phenomenon known as multisensory perception, is to get other senses, such as sight and smell, involved in the tasting experience. In this cognitive approach, consumers may use color, for example, to recall past experiences to determine how a food should taste. In a study with low-sodium barbecue sauces, research demonstrated that consumers expected darker-colored barbeque sauces to be saltier than lighter-colored ones, and these expectations influenced actual perceptions of salty taste. Other research found similar results with chicken soup. Seeing a more intense brown color generated higher saltiness ratings from consumers when the chemical difference was not there. Researchers also have shown the aroma of tasteless soy sauce can enhance the perception of salty taste.
Another chemical-related approach uses so-called “salt substitutes” to reduce sodium in food. One such ingredient, potassium chloride, can deliver salty taste without the sodium. The problem with potassium chloride is its bitter and metallic aftertaste. To counter this, researchers combined potassium chloride with a bitterness blocker to coat roasted peanuts. They were able to replace up to 90% of the sodium chloride on low-sodium roasted peanuts with potassium chloride without compromising product acceptance. A health benefit statement regarding sodium reduction significantly improved consumer liking and purchase intent of the peanuts.
In another study, sensory optimisation with cheddar cheese used a salt, salt substitute and bitterness blocker mixture. An acceptable low-sodium cheddar cheese was obtained by using up to 60% potassium chloride in the mixture.
Altering the structure of foods can also affect taste perception. Scientists used a technique called foam-mat drying to decrease the density and size of commercial salt crystals. These smaller particles, in combination with soy sauce aroma, increased the perception of saltiness in roasted peanuts using slightly less sodium. By increasing the level of oil in emulsions (mayonnaise and salad dressings), reduced levels of sodium chloride and potassium chloride could still be perceived as saltier.
Overall, about 2,000 consumers have participated in sodium reduction research at the Sensory Services Lab. This area of study is important as sodium overconsumption presents an urgent public health concern. By exploring innovative solutions to this problem, AgCenter researchers have shed light on potential strategies to effectively lower dietary sodium without compromising taste.
Ryan Ardoin is a graduate student, Jose Alonso and Pitchayapat Chonpracha are former graduate students, and Witoon Prinyawiwatkul is the Horace J. Davis Endowed Professor in Food Science in the School of Nutrition and Food Sciences.
(This article appears in the fall 2019 issue of Louisiana Agriculture.)
Consumers taste food under different lighting at the LSU AgCenter Sensory Services Lab, where researchers explore the influence of color on salty taste. Photo by Olivia McClure