Sodium Shakeout: Savory with Less Salt

The news must’ve sent product developers diving below their benchtops in shock. On June 13, 2006, the American Medical Association (AMA), Chicago, issued a statement taking the food industry to task for, in the words of AMA board member J. James Rohack, “their current practice of adding unhealthy amounts of sodium to their products.” The group then outlined a list of remedies, including halving the sodium in foodservice and processed foods over the next decade, stepping up education efforts to inform consumers about the benefits of moderate sodium reduction, and clarifying labeling vis-à-vis sodium, with warnings added to the most egregiously saline offenders.

But with all the focus on trans fats and high-fructose corn syrup, we could be forgiven for paying selective attention to what the gadflies at the Washington, DC-based Center for Science in the Public Interest (CSPI) call the “forgotten killer.” Even if salt isn’t the unsung assassin CSPI accuses it of being, the brewing battle over sodium’s health effects—and the need for its reduction in prepared foods—has been simmering on the backburner for years. Now, however, it may be fixing to boil over.

The boiling point 

Why cut back on salt? The average American consumes somewhere in the neighborhood of 6 to 10 grams per day, according to the American Heart Association (AHA), Dallas. With salt approximately 40% sodium by weight, that works out roughly to the equivalent of 2,900 to 4,300 mg of sodium.

Those sodium totals matter because, according to the National Heart, Lung, and Blood Institute (NHLBI), Bethesda, MD, “There is a clear causal link between habitual sodium intake and blood pressure. The evidence taken as a whole is sufficiently strong to warrant a specific recommendation about reducing dietary salt intake.”

Other factors such as heredity, race, insufficient consumption of calcium, magnesium and potassium, and overall health also influence blood pressure. Nevertheless, the NHLBI cites results from its own INTERSALT trial, along with those of large-scale population studies, showing that “lowering sodium intake by 100 mmol (about 2,300 mg) a day—from 170 mmol (about 3,800 mg) to 70 mmol (about 1,500 mg)—is associated with a 3 to 6 mm Hg reduction in systolic blood pressure.” Among the general population, that would lead to 11% fewer strokes, 7% fewer coronary events and 5% fewer deaths.

With 65 million American adults—almost one-third of us— suffering from hypertension, and with hypertension tied to America’s number-one killer, cardiovascular disease, as well as stroke and other conditions, the healthcare costs alone warrant taking the issue seriously. Thus, the NHLBI, AHA and the 2005 U.S. Dietary Guidelines for Americans all recommend healthy people consume no more than 2,300 mg of salt (about 1 teaspoon) per day. Groups at risk, such as African Americans, the middle-aged and elderly, and those with high blood pressure should pare back to fewer than 1,500 mg per day.

All in good taste 

There’s one reason why so many of us max out our daily sodium limits by the time we’ve had our first coffee break: It just tastes so good. And taste is the operative word: Like sweet, sour, bitter and umami, salty is a fundamental taste whose appeal is virtually hardwired into our DNA. “I’ve never met anybody who doesn’t like the taste of salt,” says Naomi Novotny, vice president and cofounder, SaltWorks, Woodinville, WA. “We’re so programmed to like that taste, and I think part of that is because it is so essential to our well-being that it’s just one of those things that we crave.”

She’s not kidding, according to Ray Salemme, Ph.D., CEO, Redpoint Bio, Cranbury, NJ. “When you taste salt, it’s a pleasurable experience and it tremendously enhances the taste of many other foods. There’s absolutely no doubt about that,” he says. “The reason that this response has evolved, and the reason that people and, actually, animals have connected it to a pleasurable response is that salt is something that you need as a living organism to maintain all kinds of ionic balances within the body.”

The evolutionary reasoning goes like this: Early humans who took a liking to salt were more inclined to consume essential sodium, along with associated nutrients. More nutrients led to better health, better health led to preferential survival, preferential survival led to increased reproductive success and, eons later, our salt-seeking genes remain an artifact of that natural selection process. “You have sensors for sugar or carbohydrates, which are appetitive, because those are things you need for energy,” Salemme explains. “You have sensors for savory, which are amino acids or nucleic acids, because that’s the protein that you need to get. And you also have an appetitive taste for salt because, as a free-moving animal, you’re constantly excreting salt and taking salt in, in order to maintain your ionic balance.”

One of a kind 

That raises the question of how, physiologically speaking, we taste salt in the first place. As it turns out, the mechanics of salt perception are actually quite simple. Sodium ions enter the taste cells on our tongues through embedded ion channels. Once inside, they trigger a signal that sensory neurons transmit to the brain for recognition as salty. Because this ion channel is unique to sodium, “that makes it almost, I’d say, impossible to replicate completely,” says Markus Eckert, technical vice president, flavors, Mastertaste, Teterboro, NJ.

Similar channels exist for compounds like potassium chloride— salt’s most common substitute— but the sensory signals it sends just aren’t the same. “Potassium chloride is very bitter compared to sodium, and it enhances metallic notes,” Eckert explains. Use it to replace salt in a chicken broth, he says, “and it would make that profile lean more towards an almost red-meaty type just by changing the minerals there.”

That’s one of many exceptional sensory qualities that make salt’s seamless substitution one of the most difficult magic tricks to pull off. “Salt is complicated in how it performs, or tastes, in our mouths,” says Kim Gray, senior applications scientist, Givaudan, Cincinnati. “There is the up-front salty burst, followed by mouthfeel or fullness, finished off by other attributes around salt,” she says. “Full-salt products have a fairly rounded taste to them and, after the initial burst, the salty character lasts a long, but pleasant, time. This is why replacing salt with a single ingredient is so difficult, because there is no one ingredient that does all of this.”

Salt can potentiate sweetness. “At lower levels, some people actually perceive salt also as sweet,” Eckert says. “So, if you’re looking at high-sugar solutions beyond a level of around 30%-plus, 0.2% of salt can almost replace 2% of sugar, in combination with sweeteners.”

George Lutz, technical services manager, quality assurance, Cargill Salt, St. Clair, MI, adds: “Salt has a wonderful ability to improve the perception of flavor in a variety of foods. For example, the properties of salt produce a chemical reaction that makes a fresh tomato taste even better. The salt neutralizes the acids of the tomato and sweetens the taste.”

Or, as Novotny says, “it’s like how you can put salt on a grapefruit and that makes it taste sweeter.” Recreating salt’s power both to amplify and to balance flavors confounds formulators seeking to reduce and replace it.

Salt is also the quintessential salivation agent. “That’s why it’s used in a lot of snacks and appetizers,” Eckert points out, “because when they’re served, they trigger your appetite for the main course.” One other quality people don’t often attribute to salt is its effect on texture and mouthfeel. “It provides solids, of course,” he says. “So, if you’re looking at low-sodium formulation and you’re taking out a couple of grams, you’ve got to replace them with something.” Typically, another crystalline material will do but, without it, “you’re definitely losing mouthfeel and you’re losing texture, as well.”

Tough customers 

We miss salt’s texture most glaringly on applications where it appears as a topical seasoning: pretzels, crackers, nut mixes and chips. As Kathi Sparks, flavorist, Wild Flavors, Inc., Erlanger, KY, points out, “The first component off a chip that hits the tongue is the outside salt.” So whatever you use in its stead had better be good.

“Topical applications result in the direct dissolution of the material on the tongue,” Lutz says. So, a suitable substitute would have to undergo the same immediate dissolution while also cranking up the salivary juices as salt does. Furthermore, while internal uses can count on the product’s full seasoning matrix to distract the palate from the missing sodium, surface salt often flies solo. “There is little to no masking of any off tastes by the nose, because salt is one of the few materials that can be detected solely by the tongue,” he adds.

Physical limitations also hamper topical salt replacement. “The seasoning on a snack has to be dosed at a certain rate,” Eckert explains, “so there has to be a certain quantity that you have to apply to get even distribution on your snack.” And those dose rates are fairly high, he adds— running anywhere from 3% to 8%. In the past, “a significant amount of that was salt,” he says. But now that we’re cutting back, “you’ve definitely got to look at other bulk ingredients to make up for that.”

Then there are applications where salt performs a necessary functional role, “such as in processed meats, cheeses and doughs,” says Scott A. Harris, director of marketing, Givaudan. (See sidebar, “Salt: First in Functionality,” for more.) Replacing or reducing salt here frequently proves quite difficult, he says, “as levels can only be lowered to a certain minimum threshold.”

Ironically, these are the products feeling the greatest pressure to go low, “as these are the highest sources of sodium,” notes Otis Curtis, business development manager, DSM Food Specialties, Savory Ingredients, Eagleville, PA.

Out with the old

Perhaps lowering sodium never became the rallying cry for consumers that lowering fat or calories did because the limited and flawed tools have soured consumers on reduced-salt fare. The sensory shortcomings of potassium chloride, as noted above, are legion—a weakness only compounded by ingredient sensitivities in some people and inconsistencies in global regulatory regimes “where some do not allow for the addition of potassium chloride, or cap the total inclusion level,” notes Harris.

Meanwhile, savory enhancers like hydrolyzed vegetable proteins (HVP) and autolyzed yeast extracts (AYE) have filled in as our next-best options. Their lysis, or breakdown, releases peptides and amino acids—and, in the case of the yeastbased products, cellular contents such as monosaccharides, nucleotides and mineral salts—that heighten a food’s savory notes (more on how below). But a growing cohort of natural-foods consumers—for whom you’d think yeast- and vegetable-derived ingredients would be welcome alternatives to much-maligned MSG— now reject HVP and AYE as MSG in disguise. As if that weren’t bad enough, yeast and vegetable flavor enhancers also “can impart a flavor of their own and change the profile of a product,” says Sparks. Thus, while flavor houses tirelessly develop masking agents to combat such drawbacks, we’re still searching for that single, self-contained, successful substitute that will take the place of salt.

In with the new 

We can quit searching, say the experts, because an all-in-one answer just doesn’t exist. “There are no magic bullets in the market,” says Curtis. “But formulators are indeed getting better at using multiple strategies to reduce sodium in food.” One of the areas where we’re making the greatest headway is in more effectively exploiting the power of the fifth taste—umami—to pull some of the savory weight when salt goes missing.

Like salty perception itself, this salty-umami synergy—the trick behind how the flavor enhancers above work—may be a product of our caveman past, too, Salemme explains. “Through evolution, we’ve learned to combine our sense of salt and our impression of how it tastes with certain other sensations and other receptors binding molecules at the same time and in ways that make the salt taste synergistic.” Umami stimulants like the amino acids glutamate and aspartic acid, MSG and the 5' ribonucleotides, disodium 5'-iosinate (IMP) and disodium 5'-guanylate (GMP), attach to G-protein-coupled receptors (GPCRs) on the taste cell surface, activating the protein gustducin and setting in motion a sequence of events that ultimately tells the brain, “umami.” “When you turn that savory receptor on,” he says, “it also turns out to have the effect of increasing the apparent saltiness of food.”

Of course, we knew this intuitively before we knew it scientifically, and mankind has exploited the relationship for centuries in fermented products like soy sauce, miso paste, fish sauce and even cheese. Fermentation of proteins in the soybean, fish and milk liberates the glutamate and aspartic acid so critical to umami character, making these ingredients among the earliest functional flavor enhancers. Predating them are other “natural” umami powerhouses, such as kombu kelp, mushrooms of all sorts and even red, ripe tomatoes—all known for their high glutamate content. Current research shows that shiitake mushrooms in particular have the added kicker of both free glutamate and the ribonucleotide guanylate, the combination of which helps explain why vegetarians look to shiitake as Mother Nature’s “cheat meat.”

But meaty hunks of shiitake are little help to a product developer working on a low-sodium chicken stock. And while fermented fish sauce may enhance the savoriness of a salt-reduced alfredo sauce, it enhances the fishiness, as well. Mushroom powders eliminate the visual and textural roadblocks to using fungi for umami enhancement, although they don’t totally sidestep the flavor issue. Colorless soy sauce powders have acquitted themselves as functional umami ingredients, too, but mainly in applications that can tolerate a little soy-sauce character. Soy sauce manufacturer Kikkoman, Walworth, WI, offers a natural, powdered flavor enhancer made from fermented wheat that not only has a neutral, mild bouillon character, but provides a label-friendly replacement for MSG and vegetable and yeast extracts.

It also provides salt, somewhat compromising the sodium-reduction purpose. Unfortunately, it’s a necessary evil of umami boosters like soy sauce, miso and other fermentation products that they contribute no small measure of sodium themselves to formulations. Regular soy sauce kicks in around 1,000 mg sodium per 18 grams (1 tablespoon), although low-sodium versions range from about 300 to 800 mg. True, their flavor-enhancing properties allow for salt reduction elsewhere, and a little of these ingredients goes a long way. However, they’re not a universal solution.

The wrinkle with new umami strategies is they capitalize on savory tastants beyond MSG, IMP and GMP. “I think that there may be new types of umami enhancers that will be more effective at enhancing salt,” Salemme says. Some of these might still reside in the nucleotide and amino acid class, “or they might be chemical compounds that resemble those,” he says. But he believes this new generation of ingredients will do a better job of enhancing salty perception independent of any contribution from potassium chloride— thus reducing its bitterness faults. However, he points out, “I do think that we’ve already been able to make some products where we’ve removed about 50% of the sodium chloride, replaced it with potassium chloride and a variety of savory enhancers, and it’s quite an acceptable product.”

Substituting with systems 

When it comes to salt-replacement ingredients, a systems approach to nutritional reformulation is exactly what we need.

“Salt reduction and flavor enhancement products need to be designed for each application to have total commercial appeal to the consumer who wants low-sodium products to taste like full-sodium,” Gray says. “As we learn more about the interaction of salt and the physiological mechanism, we are better equipped to address attributes such as masking and enhancement, and deliver the desired goal.”

Or, as Eckert puts it, “It’s more like a jigsaw puzzle.” To put the pieces together, he says, “we typically do a sensory profile on the full-salt product. Then we would do a sensory profile on the salt-reduced product to identify the shortfalls of reducing the salt. And then you’d address every single attribute individually, and then you’ve still got to balance them.”

Take the case of a classic chicken soup. “You would have a certain profile of saltiness, but you also have a certain profile on mouthfeel,” Eckert says. You’ve got to consider the poultry-type meatiness and characteristic fatty notes, both of which salt potentiates. “And it gives you a bit of texture. It triggers salivation, which fits nicely into the fatty profile, as well,” he adds. So, if you were to remove 50% of that salt, you could replace it with, for example, an appropriate amount of potassium chloride. But, while that restores some of the salivation, “it changes the character of the way people would now describe the chicken broth,” he says. “It was a nice, cooked, white-meat profile before; they’d say now that it’s more red-meaty. You’re also suppressing some of the volatiles of the flavor, so the aroma is not as good as it used to be.”

A satisfactory solution would account for the full complexity of this target profile rather than just the saltiness itself. “You’ve got to rebuild more of the flavor profile of the meat. You’ve got to bring the salivation to a similar level. You’ve got to address the issue that your aroma may not be on par with the target. You look at it more as a flavor system,” says Eckert. To be sure, potassium chloride can play a part in that system, but you’d also look to the armamentarium of umami stimulants, from yeast extracts to nucleotides. “You would probably add some of the white-meat chicken notes to bring the meat profile back up. And you would probably work with some fatty acids to get the texture back into the product, too,” he adds.

But don’t expect perfection. “In some cases you’ve got to compromise,” Eckert says. You may get the overall flavor profile back up. You may get the mouthfeel almost there. But you may not get the saltiness of the full-salt product. But, as long as you get on par with your full-salt product in terms of overall consumer acceptance, then you definitely have a superior product to the product that had just been reduced in salt.”

Making it work 

What does this mean for on-the-ground formulation? Everyone from flavor houses to dairy processors to salt suppliers themselves is proposing new “ingredient systems” for addressing salt reduction before it becomes a crisis.

According to Sparks, the general trend toward healthful formulation has given the flavorists at her company experience working with vitamins, nutraceuticals and other ingredients notorious for their off flavors. “Through this learning,” she says, “we have designed a technology, SaltTrim, that uses the benefits of potassium chloride while eliminating the undesirable notes.” By clipping off the bitter and metallic tones while building in sweetness and acidity, it “enhances the whole profile to make the reduced-salt version taste like the full-salt product,” she says. She also notes that all-natural Savor- Crave is an umami-enhancing taste modifier handy for when you need to “intensify flavors and create mouthwatering characteristics in savory products.”

If you’re wondering what whey proteins have to do with low-sodium formulation, the technologists at Grande Custom Ingredients Group, Lomira, WI, can tell you. Their Grande Gusto natural flavor enhancer is a dairyderived ingredient captured from the whey stream that “contains relatively low levels of sodium”— 2.89% to 3.00%, depending on the specific ingredient—“but has a very salty perception,” says Michelle Ludtke, senior food technologist at the company. “Grande Gusto does a nice job of enhancing the salt flavors that are already in the food system,” without introducing any of potassium chloride’s bitterness, she says. “It also offers a very clean label. It can be labeled as a ‘Natural flavor. Contains milk.’ It can also be used in a wide variety of food applications.” Being a liquid, it’s not suited for topical applications unless spray-dried as a slurry. But dips, dressings, sauces, soups and baked goods are all solid candidates for use.

Food Chemical Codex standards specify the purity level of salt. Nonetheless, low-sodium salts give formulators another option for cutting sodium levels. “Low-sodium salts may be blends of salt with other ingredients; less-pure forms of salt; or low-bulk-density salts that, by volume, yield lower sodium levels,” Lutz says. And, while low-sodium blends have fallen short in the past for the bitterness of their potassium component, processors are getting savvier at formulating them.

Wixon, Inc., St. Francis, WI, makes a product called KClean Salt, a 50%-lower-sodium blend made of equal parts sodium and potassium chloride. What improves it over its predecessors is the inclusion of “a proprietary taste modifier technology to mask the objectionable bitter aftertaste of potassium chloride, consequently allowing for a clean salt taste that consumers like,” says Mariano Gascon, flavor laboratory director, Wixon. Unlike other sodium replacements, “it is not a blend of powders and crystals that lead to stratification,” he says. Rather, it’s a “homogenous crystalline product that looks, behaves and tastes like salt.” Appropriate for topical application, “it can be heated, frozen, boiled and packaged in virtually any application where you need salt.”

Low-bulk-density salt, another low-sodium alternative, is standard sodium chloride with less sodium by volume. Cargill’s Alberger brand is one such example, with “a unique hollowed-out pyramidal structure that delivers dramatically different taste perceptions,” Lutz says. “Its irregular surface and low bulk density provide a maximum flavor burst to potato chips, and its rapid solubility avoids the gritty aftertaste on crackers and breadsticks.” And its utility transcends topical applications. “Rapid solubility also ensures good mixing and dispersion in blended meats and aids in the formation of rich, creamy emulsions,” he says.

With naturally evaporated sea salts growing in popularity, it’s no surprise that this premium category would also respond to requests for low-sodium options. “We have gotten so many calls for a low-sodium sea salt,” says Novotny, whose company supplies imported and domestic specialty salts. They’re actually road testing one right now. Although not technically a sea salt, “it is an all-natural, solar-evaporated salt” that naturally crystallizes as a blend of sodium and potassium chlorides, with associated trace minerals. “When you taste it, it’s very salty,” she says. “It doesn’t have that bite that salts with potassium added to them have. And the potassium is all part of the crystal, so you don’t get that chalky part” that plagues manufactured sodium-potassium blends, she says. At about 30% to 40% less sodium, she thinks it has potential. What’s more, “you use less of it because it has a much more rounded taste,” and the trace mineral content, she claims, “helps your body regulate the sodium better.”

“I believe that people buy flavor,” says Reid Wilkerson, president, McClancy Seasonings, Fort Mill, SC. “The American palate is changing to where they’re definitely interested in looking at more flavorful foods.” On the surface, this wouldn’t seem to jibe with sodium reduction. However, he thinks “your best ally in replacing sodium” may be turning robust flavors to your advantage. He’s bullish on the ability of heat the trigeminal response from substances like piperine in black pepper, gingerol in ginger, isothiocyanates in mustard, and of course, capsaicinoids in chiles to distract the palate from diminished saltiness. “As you increase the amount of heat in different profiles, I’ve noticed that the need for more sodium in that profile is reduced,” he says. Garlic helps, too. “You can do a roast garlic profile with almost no salt. It’s a very satiating flavor.”

Looking further down the pike, biotechnology may soon serve up sodium solutions of its own. Salemme says that some biotech companies are trying to develop salt-replacement technologies by acting on salt receptors “to amplify the actual signal from the receptor that’s responsible for creating the sensation in the first place,” he says. The possibility of reducing sodium without having to add anything in its place is alluring.

Until that happens, we can satisfy ourselves— and our consumers—with the improving lot of technologies on offer now. “Initially, all that you could do was create a 10%, 15% reduction,” Eckert says. “The trend is clearly more toward 33% now, and in some applications, there are even requests for more than 50% reduction.” The better the sodium-reduction system, the lower we’ll be able to go.

But in the end, as Lutz says, “Nothing can beat the true taste of salt.” 

Kimberly J. Decker, a California-based technical writer, has a B.S. in Consumer Food Science with a minor in English from the University of California, Davis. She lives in the San Francisco bay area, where she enjoys eating and writing about food. You can reach her at [email protected]. 

Salt: First in Functionality

Salt didn’t wind up everywhere just because it’s so fun to dump into the hopper. It was probably mankind’s first functional ingredient, aiding food production since prehistory, primarily as a preservative. By altering the osmotic pressure in foods, it renders them inhospitable environments for most bacteria, which lose moisture to the briny surrounding solution and eventually shrivel up and die. This protects food from spoilage in the case of putrefying bacteria, and it protects us from illness in the case of pathogens.

But this is only the most obvious example of salt’s functions. For instance, have you ever tried making bread without it? If so, you probably didn’t like the results. “Salt acts as a texture aid, strengthening the gluten in bread dough,” says George Lutz, technical services manager, quality assurance, Cargill Salt, St. Clair, MI. Without it, you don’t achieve the proper rise or consistent crumb grain you’d expect in the finished loaf.

By helping proteins bind water, salt is also indispensable in developing the firm, smooth texture that characterizes processed meats, while also holding water within these products so it doesn’t weep off during cooking. Salt increases the solubility of muscle proteins, allowing them to cohere and form a stable emulsion with dispersed particles of fat, creating the tightly bound meat-fat-water gel that we recognize as sausage or formed meat.

Salt controls fermentation in breads, pickles, cheese, sauerkraut, fermented sausages and other fermented foods, too. “Salt also draws out foods’ true flavors and juices through techniques such as brining,” Lutz adds. And one of the biggest drawbacks to nitrate- or nitrite-free ham, bacon or hot dogs is the absence of that characteristic pink hue—a color that develops only when those nitrates interact with sugar and, yes, salt.