Yet that is just what they may be getting, as surprising quantities of salt--and sodium--lurk across the product spectrum, from soups to nuts. And not without reason, either: Salt is a uniquely functional compound, capable of everything from improving texture and ensuring preservation to striking the flavor balance consumers appreciate in their favorite foods. Cutting even just a little can tip that balance.

However, calls for sodium reduction grow louder by the day, particularly in the soups, stocks and stews that are prime targets for sodium critics. So, soup manufacturers need a sodium solution that not only replaces excess salt but restores flavor balance, as well. Like those hidden sources of sodium, their secret salt-cutting weapon may be where they least expect it: in the red, ripe tomato.

Cause for Concern

Ehud Zach, food applications manager, LycoRed, notes that sodium is essential for health. “But current sodium consumption,” he points out, “is much higher than the body needs.” How much? The Institute of Medicine (IOM) sets 2,300mg of sodium per day as the tolerable upper limit for most Americans, tightening that to an adequate intake of 1,500mg per day for at-risk groups like older consumers, African-Americans and people with hypertension, diabetes and chronic kidney disease. Yet the average American, meanwhile, consumes 3,436mg per day—far more than advised.

Intake levels this high correlate with increased rates of hypertension, which itself increases risk for heart disease, stroke and kidney ailments. A study published in 2011 in Circulation examined data from the National Health and Nutrition Examination Surveys (NHANES) I and III and found that the death rate from all causes among hypertensive participants in the first survey (1971-1975) was 42% higher than for those without, while hypertensive respondents in the later survey (1988-1994)had a 57% higher death rate than those without. “A daily reduction of one-quarter teaspoon of salt from the diet could prevent 100,000 deaths a year,” Zach observes, “saving the healthcare system some $24 billion.”

Pressure’s On

No wonder regulatory agencies, health professionals and consumer advocates are sounding the sodium alarm. Consumers are hearing the message, with 66% of  those surveyed in Mintel’s Soup – U.S. – January 2011 report claiming that lowering their salt intake would improve their health and diet.

“The U.S. FDA, Health Canada and the Food Standards Agency (FSA) in the U.K. all recommend consumption of no more than 6g salt per day, or 2,300mg of sodium,” Zach says. Given the excess sodium contribution from many packaged and processed foods, he suggests that sodium content “should not exceed 430mg per 100g of finished product. In our own work on low-sodium applications development, we aim for salt reductions of 25%.”

The Umami Answer

With the sodium content of most soups falling between 500-1,500mg per 100g serving—roughly 1.3-4.0g salt—such reductions sound ambitious, if not improbable. Traditional sodium-reduction strategies involved replacing salt with substitutes like potassium chloride (KCl), which not only introduces metallic off notes of its own, but fails to maintain the flavor intensity and balance of its sodium-containing cousin.

So formulators and sensory scientists alike have had to look elsewhere for alternatives. Of interest is the work of Kikunae Ikeda, a chemistry professor at the Imperial University of Tokyo, who recognized that foods like the kombu kelp and dried fish flakes used to make the Japanese soup stock dashi possessed an ineffable “deliciousness” that he gave the Japanese name umami. After studying umami’s chemistry, Ikeda determined it to be the product of the amino acid glutamate, as well as compounds like inosinate and guanylate, found in umami foods.

When these umami substances interact with other ingredients in a food matrix, they enhance savory flavor and improve overall palatability. As Zach puts it, “Umami highlights a food’s saltiness without increasing its salt content.” While the scientific community has more to learn about the precise mechanisms by which umami—or the “fifth taste,” contribute to flavor , the food and foodservice industries have lost no time in leveraging the phenomenon in their formulations and products.

“In fact,” Zach says, “we can use the principles of umami to cut up to half the salt in certain foods without reducing desirability.” For example, a low-umami soup made with no glutamate needs a salt concentration of at least 0.75% to achieve palatability. “With glutamate, though, we can make that same soup taste palatable with a salt concentration of just 0.4%.”

Red Alert

Food processors have traditionally used a number of industrial ingredients to achieve umami. Monosodium glutamate (MSG), the 5’-nucleoties inosine monophosphate (IMP), guanylate monophosphate (GMP) and adenosine monophosphate (AMP), hydrolyzed vegetable proteins (HVP) and enzymatically treated yeast extracts all enhance umami flavor in reduced-sodium formulations.

Ikeda was ahead of his time in identifying umami not in artificial chemicals but “in the complex flavor of asparagus, tomatoes, cheese and meat,” as he told the Eighth International Congress of Applied Chemistry in 1912. Then and today, home cooks turn to these natural sources of umami to create its signature deliciousness—whether they are familiar with the concept or not.

Zach calls particular attention to the tomato. “We now know that one of the reasons why the tomato is such a reliable source of umami is its high level of free amino acids—including glutamate—which act in synergy with other tomato components to enhance savory,” he says. “Any seasoned cook will praise the tomato as a wonderful ‘mixer’ in soups, stews and sauces, where it blends and enhances the overall flavor balance.”

Next-Generation Flavor Enhancement

While a touch of tomato juice stirred into a steak sauce may brighten a low-sodium formulation, the same ingredient would not be appropriate for other applications -- a delicate cream of celery soup, for example. “Not every product can accommodate the overt character of tomato ingredients,” Zach notes. That is why he and his LycoRed colleagues distilled the umami power of the tomato to its essence, creating a revolutionary new flavor-enhancing solution for low-sodium foods.

The product—a 60° Brix tomato serum concentrate—is called Sante. “That knowledge and understanding allowed us to separate and concentrate the free amino acids and other components most responsible for the savory-enhancing qualities of red, ripe tomatoes,” Zach says. Product-formulation research is proving very positive. “We’ve found that by enhancing flavors naturally with Sante, we can significantly reduce the added salt in products while maintaining taste appeal.”

Enhancement in Action

For example, when 0.2% MSG in a standard chicken soup was replaced with an equivalent quantity of Sante liquid, the salt/sodium content was reduced by 25%while preserving a high flavor quality. “We also ran several trials using the powder form of the ingredient in a commercial dry pea soup mix,” Zach says. “We found it allowed for the partial or total replacement of standard flavor enhancers, lowering salt, too.” Used at 0.96% in the hydrated soup, the tomato powder replaced all MSG and reduced salt by 15%.

Even greater  reductions of up to 50% of the salt in a soup formula have been achieved. Even then, he says, the sensory results have been impressive. “Reduced-salt soups can have rough, ‘peaky’ tastes that make the whole profile seem unbalanced,” Zach points out. “Our product smoothes those peaks, so the finished soup tastes more cohesive and, ultimately, more satisfying.” The ingredient also appears to improve a flavor’s dwell time in the mouth, as well as perceptions of mouthfeel and texture.

Zach finds this a particularly intriguing characteristic, as it implies that Sante—in addition to generating umami—is also a source of kokumi, a sensory phenomenon that scientists have only recently begun to investigate, and yet it already attracts interest among product developers and researchers alike. “Kokumi encompasses several main sensations,” Zach explains. “There’s the initial flavor impact, the duration of the pleasing flavor and, finally, that all-important flavor balance and mouth filling quality.”

Kokumi is not so much a flavor or taste in itself, he continues, but a sensation of continuity or “heartiness” that adds to a food’s appeal. “We believe that Sante contains compounds, including amino acids, that provide kokumi by enhancing taste and flavor, as well as the dwell time and fullness, of the other tastants in a formulation,” Zach says. “We’re still in the early stages of understanding how it works, and once again, we’re reminded of the importance of amino acids. In the case of Sante, Zach and his co-developers achieved high amino acid content through their unique process of vacuum-concentrating the separated tomato serum, as well as their insistence on starting with ripe tomatoes. “As the tomato ripens,” he explains, “its glutamic acid concentration rises sharply. So by using ripe tomatoes, we optimize the glutamic acid in the finished product.” At 32.2% of the amino acid total, the glutamic acid in Sante is 12 times higher than in the original tomato.

The Natural Solution

Zach notes that his company’s clients are often “very concerned” about not just sodium, but their ability to cut its levels without recourse to “chemical-sounding” ingredients like the artificial flavor enhancers mentioned earlier. “Avoiding these fallbacks is very important because of today’s market focus on ‘natural’ and ‘clean’ labels,” he says. “Anecdotal evidence implicates MSG in triggering allergic responses, and uncontrolled reactions can occur in the production of ingredients like HVP and yeast autolysates.”

By comparison, LycoRed’s all-natural flavor enhancer offers an ingredient made from GMO-free tomatoes via a physical process with no chemical intervention. On labels, it can appear as “tomato concentrate,” “tomato serum concentrate” or “tomato flavor” depending on local regulations. This provides  formulators what Zach calls “an important marketing advantage for customers who demand a clean label.”

However, some still may wonder: Will my Cheddar-broccoli soup taste like tomato juice? “Formulators should keep in mind that Sante liquid carries some tomato flavor, and that all reformulations need organoleptic scrutiny,” Zach says. “But over the years, we’re learned so much about the properties of our products and how to extract targeted elements from the tomato without bringing along obvious taste or color that we think we’ve really made a breakthrough here.”

Typical use levels are minimal. “The average dose is very low--0.35%-- so it won’t contribute an off taste in the finished product,” Zach notes. “All it contributes is a savory, balanced, umami deliciousness--and at the lower sodium levels that food manufacturers were aiming for in the first place.”