By Donna Berry, Contributing Editor
With the media continually reporting that Americans consume too much salt, keeping sodium content low is a priority for most food designers. Recently, for example, the Center for Science in the Public Interest (CSPI), Washington, D.C., recently showed that some food labels understate the calories, sodium and saturated fat consumers are likely to get from certain products, since the declared serving sizes are much smaller than actual serving sizes.
Canned soup presents the most-dramatic example of how unrealistic the stated serving sizes are, according to CSPI. Labels for Campbell’s Chunky Classic Chicken Noodle soup indicate a serving is 1 cup (a little less than half a can) and has 790 mg of sodium—about half the sodium most adults should consume in a whole day, according to recommendations by various medical and nutritional authorities. But, according to a national telephone survey commissioned by CSPI, 64% of consumers eat the whole can at one time, so they consume 1,840 mg of sodium, more than a day’s worth for many adults. Only 10% of consumers said they eat 1-cup portions.
“Given the prevalence of hypertension, heart disease and stroke in America, we need accurate food labels that would ensure that consumers really know what they’re likely to consume," says Michael Jacobson, executive director, CSPI. “The FDA should define serving sizes to reflect what consumers actually eat, as the law requires, not what the soup industry pretends that they eat."
The science of salty
Sodium and salt are not the same. The ingredient commonly known as “salt" is sodium chloride with 39.34% sodium and 60.66% chloride on a molecular-weight basis.
Sodium is found naturally in many foods. In addition, prepared and processed foods often contain salt or other sodium-containing ingredients, such as the leavening agent sodium bicarbonate, also known as baking soda
To reduce sodium in convenience foods consumers want and still keep them tasting good—the No. 1 criterion for purchase—food technologists must gain a better understanding of the basic taste of salty.
“Salty is one of the five basic tastes, which also include bitter, sour, sweet and umami," says Joseph Formanek, associate director, business development and application innovation, Ajinomoto Food Ingredients, Chicago. “Salty is one of the ‘positive’ taste attributes. Sweet and umami are the others. Bitter and sour are considered negative. The theory is that the body adapted to recognize foods in nature that are nutritious and beneficial, and such foods typically exhibit the positive taste attributes. Sour and bitter tastes are usually exhibited in foods that are poisonous, have perished or are not as nutritious as those with positive tastes."
However, the problem with defining saltiness, adds Mariano Gascon, vice president of research & development, Wixon, Inc., St. Francis, WI, “is similar to the layman’s attempt to define a specific color. The difference is that colors can be scientifically described by a particular wavelength, but such reference does not exist when it comes to taste. Thus, taste can be simplified as a chemical sense that is caused by chemical reactions, and we have established chemical reference substances that serve to demonstrate them.
“By this definition, saltiness is a demonstrable taste, and it is clear that table salt has been established as a chemical reference substance that serves to demonstrate saltiness," Gascon continues. “No other compound seems capable of identically duplicating the saltiness character of sodium chloride. This makes it very difficult to find a substitute that elicits the same taste characteristics. Though this is an oversimplification from the chemical point of view, from the psychological view, when certain substances are combined, they can create a ‘new’ taste in the same sense that mixing colors leads to a new shade of a known color. They are close, but not exact. This analogy helps explain the enhancing properties that salt has on other food flavors."
At the 2011 IFT Annual Meeting & Food Expo in New Orleans, Leslie Stein, senior research associate and director of science communications, Monell Chemical Senses Center, Philadelphia, gave a presentation entitled, “Foundations of Salt Perception to Build Your Research." She started out by saying, “Salt is a magic ingredient in food."
In the presentation, Stein confirmed what the food industry knows: “We still don’t know how the salty taste works, but we are getting closer." And, to answer the question why humans like the salty taste, she said: “Because it tastes good! Humans evolved to like the taste of salt."
Meredith Bishop, principal development scientist, Spicetec Flavors & Seasonings, Omaha, NE, adds: “Early on, humans learned that salting foods preserved them by retarding spoilage and making the food last—and taste good. Scientists are just starting to learn how humans perceive sodium chloride on the tongue. We seem to have an innate response to salt—we just like the taste."
