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.”