Reducing Sodium, Maintaining Flavor and Functionality

By Cindy Hazen, Contributing Editor

According to an April 2010 report from the Institute of Medicine (IOM), Strategies to Reduce Sodium Intake in the United States, the average American consumes about 50% more sodium than recommended in the Dietary Guidelines for Americans. Currently, average consumption is more than 3,400 mg of sodium per day. To meet the recommended level of no more than 2,300 mg daily will require a coordinated approach, requiring new government standards for the acceptable level of sodium, according to the IOM report. Manufacturers and restaurants/foodservice operators need to meet these standards so that all sources in the food supply are involved and so that the consumers taste preferences can be changed over time to lower the amounts of salt in food.

Further, the report recommends that the FDA set mandatory national standards for the sodium content in foodsnot banning outright the addition of salt to foods, but beginning the process of reducing excess sodium in processed foods.

Excess sodium in the daily diet contributes significantly to high blood pressure, which affects nearly 75 million people aged 20 or older, according to FDA. Success in reducing sodium intake will require national coordinated action, the agency agrees. Over the coming weeks, the FDA will more thoroughly review the recommendations of the IOM report and build plans for how the FDA can continue to work with other federal agencies, public health and consumer groups, and the food industry to support the reduction of sodium levels in the food supply. The Department of Health and Human Services will be establishing an interagency working group at the agency on sodium that will review options and next steps.

A pinch of perspective

Michael G. Tordoff, Ph.D., faculty member, Monell Chemical Senses Center, Philadelphia, questions the efficacy of national mandates. The IOM is proposing a dietary experiment involving the entire U.S. population, and I think there is a strong argument to be made for some initial research to see if there is a chance such a grand manipulation will work, he says.

Tordoff splits the sodium debate into two issues. The first is whether sodium reduction will be helpful. My reading of the literature is that the greater good would be a drop in blood pressure of most people, which would lead to less chronic disease. This would be beneficial, he says.

The second issue is whether sodium restriction is truly practical, Tordoff says. My view is that stopping smoking or drinking alcohol will be easy compared with reducing sodium intake. There is a strong desire to consume salty foods, motivated by powerful physiological controls. It is unknown but quite possible that reducing the sodium intake of all foods (as the IOM recommends) will simply shift peoples preferences from what they eat now to foods with relatively high sodium content. So, even if the sodium content of every food is reduced, it wont be very helpful if we all switch from eating fruit to potato chips.

The hope is that gradually reducing sodium in food will lead to a gradual drift downward in sodium preferences. There are a couple of studies (by Gary Beauchamp and colleagues) suggesting that prolonged consumption of low-sodium foods will lead to a lowering of sodium preferences, Tordoff says. However, the studies involve perfect low-sodium diets with no relapses, and they show that it takes around six weeks to see this reduced sodium preference. On the other hand, consuming high-salt foods increases sodium preference in just 24 hours. It seems very unlikely indeed that there wont be occasional lapses of eating high-salt foods that will reset our preferences to like high concentrations of salt.

In Tordoffs view, salt replacers have limited utility from a taste perspective. The fact is that sodium taste transduction involves a very simple ion channel, and there is little opportunity to modify its action; unlike, for example, sweet transduction, which involves a relatively large receptor with multiple binding sites, and so several targets for artificial sweeteners.

Beyond saltiness

The combination of sodium and chloride has a long history of use in foods and has become a baseline for our salty taste perception, says Janice Johnson, Ph.D., applications manager, Cargill Salt, Minneapolis. But saltiness is just the tip of the iceberg. In addition to salty taste, salt also acts as a flavor enhancer, helps balance and round out the overall flavor profile, and suppresses bitterness in products such as canned vegetables, she says

Among the many functions that salt provides, in meat products, it solubilizes protein and enhances hydration, says Linda Kragt, technical services manager, Morton Salt, Chicago. It helps regulate enzyme activity in cheese and also creates the expected texture. It controls the yeast activity in yeast-leavened breads and strengthens gluten so that doughs are more machinable. In many products, salt has a preservative effect by lowering the water activity and inhibiting bacterial growth.

Salts role in controlling water activity provides the right environment for desired microbial growth in many fermented products, such as cheese and meats, says Johnson. It is critical for the non-sodium substitute to provide the same impact on water activity to ensure the desired flavor and texture profile that is attributed by the desired microorganisms.

Because sodium chloride is so adept at multitasking, its important that the product designer understands and addresses all of the attributes sodium chloride brings to the formula.

The developer should assess the roles of salt in the product and consider if other ingredients might be required to substitute for key functions that salt provides, advises Kragt. In certain products, a lower salt content may result in a reduced shelf life. It may be necessary to modify the packaging or change the processing technique. To compensate, other ingredients may have to be added or increased, such as use of a salt alternative, antimicrobials or acidulents. Any of these changes need to be tested to ensure shelf stability, as well as consumer acceptability.

Aaron Graham, director technical innovation, Griffith Laboratories, Alsip, IL, finds that reducing sodium in an existing product is especially difficult and complex when the goal is to create a product match. Because of the many functions that salt may provide, salt substitutes may be helpful in reducing sodium and producing a salty flavor or mouthfeel, but fall short in delivering the other desirable properties.

Foods that contain multiple components, such as pizza, are more difficult to reformulate because the developer may have to reduce sodium in each item: sauce, cheese, meat topping and dough. Also, products where salt has multifunctional effects, such as processed meats and poultry, are challenging to reduce sodium. A variety of approaches may be needed to provide the expected taste, yield and texture, as well as maintain the shelf life, says Kragt.

Different cheeses have a wide range of sodium levelswith lower sodium content found in fresh mozzarella and Swiss, and higher sodium content in specialty cheeses like feta and blue. Salt and low pH are two important factors that help keep cheese safe from unwanted microbial activity, and salt does quite a bit for flavor, explains Mark Johnson, interim director and senior scientist, Wisconsin Center for Dairy Research (WCDR), University of Wisconsin, Madison. In the past, we have found there is a limit on how far we can go to remove salt from cheese before people start to notice, but research on new technologies is helping change that.

Researchers at WCDR have applied for a patent on a process to make a loaf-form, low-fat process cheese using the same basic cheesemaking method used to develop a low-fat mozzarella cheese. This process involves removing sufficient calcium during the manufacture of the cheese base and replacing melting salts normally used in process cheese with emulsifiers like mono- and diglycerides. The calcium may be re-added during the cheesemaking process to provide the low-fat, reduced-sodium cheese with all the positive nutrients found in full-fat cheese, says Mark Johnson. He believes it is important to note that the salt found in cheese only makes a minor contribution (less than 8%) to the overall U.S. dietary consumption of sodium.

 Hidden sodium

A significant challenge lies in identifying and attending to the less-obvious contributors of sodium. Sodium alone is not used as an ingredient in food products, says Janice Johnson. There are many ingredients that contain sodium, and they have many functional roles, such as preservation, leavening and flavor. For example, sodium and potassium lactate both act effectively as a preservative in meat products. The developer will have to examine the sodium contribution of various ingredients in the formula and identify those that will need sodium reduction.

According to John Brodie, technical service managerbakery, Innophos, Cranbury, NJ, nearly all the sodium in baked goods comes from salt, sodium bicarbonate and leavening acids. Most formulators start sodium reduction by looking only at replacing salt, which can be difficult to replace without affecting taste, he says.

In chemically leavened products such as cakes, muffins, donuts, pancakes and biscuits, salt can contribute about 30% to 50% of the total sodium. Sodium acid pyrophosphate (SAPP), a widely used leavening acid, will contribute 20% to 35%, Brodie says. Sodium bicarbonate will contribute 20% to 35%. By replacing SAPP with a calcium-based leavening acid, you can reduce sodium by 20% to 30% in your finished product. Most companies are looking to reduce sodium by 15% to 25%.

Slower calcium acid pyrophosphate/monocalcium phosphate leavenings (CAPP/MCP) can be used as a one-to-one replacement for SAPP 28, since they both have a neutralizing value of 72. The neutralizing value of a leavening acid is the number of pounds of sodium bicarbonate that can be neutralized by 100 pounds of acid. No other changes to the formula will be needed. Calcium phosphates are bland in taste, so your products flavor profile will not change, Brodie says. It is possible to replace sodium bicarbonate with potassium bicarbonate, but you will need to use 19% more, and the cost difference is significant.

Besides a reduced-sodium declaration, an added benefit of using slower calcium phosphates is a boost to the calcium content of a product.

Another option, glucono-delta-lactone (GDL), is a sodium-free leavening agent that can be used very effectively in bakery leavening systems by replacing the sodium acids typically found in baking powders, say Peter Bradbury, market development manager, Jungbunzlauer, Newton Centre, MA. Functionally, GDL offers excellent leavening properties, clean taste profile and is a cost-competitive solution for sodium-reduction challenges. It is considered a time-delayed agent, because carbon dioxide is released over time. Because its reaction rate is accelerated by increased temperature, the rate of leavening can be controlled.

Substituting salt

Benjamin Jones, Ph.D., senior flavor chemist, David Michael & Co., Philadelphia, suggests replacing sodium with other salt compounds that taste salty. But these can have limitations. Lithium chloridetried commercially in a salt substitute in the 40sis toxic at needed levels. Calcium chloride can be bitter with a sweet-and-sour aftertaste. Magnesium chloride can add bitterness. Potassium chloride has a salty flavor similar to sodium chloride, but has a slightly metallic/bitter note. Bitterness blockers reduce the metallic/bitter aftertaste of potassium chloride and allow for a slightly higher potassium chloride usage rate, Jones says. Reducing sodium chloride is easier with products that have a strong flavor characteristic compared to relatively bland products. A 10% to 25% reduction can usually be done without detection, he says. Any more than 25% should be decreased gradually over time.

Strategies can prove application-specific. Some salt replacers that work well in soups and gravies, when applied to sausages, result in a sausage with a crumbly texture and premature loss of pink color, cautions Mike Bunczek, principal scientist, innovation, Griffith Laboratories. He finds that reducing sodium in ground meat products is often the most difficult. Sodium has a strong impact on texture, shelf life and color stabilization, he says. One suggestion to minimize this issue is to dissolve the salt substitute in water prior to addition to the product to improve distribution throughout the product.

Graham points out that it is also important to remember that optimal compositions of salt replacers usually vary with actual salt level. A salt replacer that works well at 0.75% salt level does not necessarily work as well when salt level is 1.50%, he explains.

The food scientist should keep in mind that sodium reduction will involve flavor work, since salt substitutes may accentuate the flavor contributions of other flavor components in the food product, Graham says. This necessitates working with your seasoning/flavor partner to make sure that the reduced-sodium product matches the current product. Product developers should also consider label, allergen and cost before developing low-sodium products.

As a general guideline, Mariano Gascon, vice president, R&D, Wixon Inc., St. Francis, WI, proposes that small sodium reductions can be achieved by reducing the salt by 5% to 15% without affecting the quality of the product. He recommends adding potassium chloride to compensate for greater reductions.

Although potassium chloride does not contain sodium, it has a salty component because it stimulates some of the same taste receptor cells as sodium chloride, even though the taste-transduction mechanisms for sodium chloride are different than those engaged by sodium chloride, Gascon says.

When a formula contains 25% less sodium, Gascon generally recommends using potassium chloride as a 1:1 replacement. At reductions of 25% to 50%, potassium chloride can replace sodium at 1.15:1. Its important to remember that actual percentages will be dependent on the end product.

Sodium reduction is very application-specific, Gascon says. We classify the challenge on three types: formulating foods with low water activity, formulating foods with high moisture content, and formulating foods with high fat. These three categories have the most effect on salt perception.

Potassium chloride enhances saltiness and can help restore losses in ionic strength, says Kragt. Although potassium chloride contributes saltiness, it can also provide a metallic note, so 100% substitution for salt is not advised. In addition, many flavor houses now offer masking agents or bitter blockers that can improve the flavor profile of products formulated with partial potassium chloride substitution.

Speaking of potassium chloride, Chris Warsow, corporate executive chef, Bell Flavors & Fragrances, Northbrook, IL, says: Many people perceive it as having a bitter-metallic flavor. I work with a number of masking agents that can help to mitigate those off flavors. By using flavor enhancers, you can boost the overall savoriness of the product so the consumer does not miss the salt.

Janice Johnson believes that potassium chloride is the best substitute for sodium chloride. It works well as a foundation for significantly reducing sodium in processed foods, she says. It mimics salt in ways such as texture and protein-binding, water-retention capacity, and fermentation control.

One ingredient that can be used in place of sodium chloride consists of taking potassium chloride and modifying the crystal structure to enhance the flavor to make it taste more like regular salt, says Teresa Isakson, sales and marketing director, Nu-Tek Products, Minnetonka, MN. She suggests using this product at a 1:1 replacement for sodium chloride.

In a dry application, the salty perception should be slightly more intense, and in a wet application it will be slightly diminished, Isakson says. In a wet application, any potassium-based salt will have a slightly weaker flavor perception because the potassium molecule is larger than sodium, thus giving less ions to give the salty perception.

This potassium chloride functions well in meat because it has an ability to hold onto water well in meat applications, thus improving yields, Isakson says. In a dry-coating application, it has a lot of surface area, giving an enhanced salty perception. You would not need as much of our product as regular salt to get the same salty perception in a dry application.

Because the potassium molecule is larger than the sodium molecule, Warsow cautions that when it comes to binding processed meats, potassium chloride is not as effective as salt on a weight-by-weight basis. To get the same protein extraction and water-binding capacity, you have to use slightly more potassium chloride, he says.

One salt substitute consists of sodium chloride, potassium chloride and sodium gluconate, notes Bradbury. The latter ingredient is a metal chelator, which blocks the bitterness of potassium, therefore providing a very clean taste profile and full functionality, he says. The product works well in soups, salad dressings, sweet baked goods, topical applications and meats.

Reduced-sodium solutions

In savory applications, sodium can often be reduced by decreasing salt and increasing other flavors. Kevin McDermott, technical sales manager, Savoury Systems International, Branchburg, NJ, suggests using yeast extracts as a means for reducing the sodium level in the original formulation. He recommends replacing sodium with a flavoring component, such as yeast extract, or developing new products using yeast extracts as a base flavor for flavor development.

Generally, yeast extracts will have a much lower usage level than added salt, while still providing savory flavor and overall mouthfeel, McDermott says. With the addition of the savory flavor added by the amino-acid profile of a yeast extract, a developer can reduce the amount of salt that is being added in a finished food product while not turning off the consumer to the product due to loss of the sodium flavoring component.

Well-known flavor enhancers like monosodium glutamate, (MSG), inosinate + guanylate (I+G), hydrolyzed vegetable protein (HVP) and autolyzed yeast extract (AYE) have the ability to boost flavors, including salt perception.

"Flavor enhancers such as MSG and nucleotide can boost overall flavor and salty taste by putting back the enhancement functionality that salt has," says Judy Kim, senior researcher, CJ CheilJedang, Seoul, South Korea. "So they maintain quality, even though salt is reduced in the formulation." She says MSG is most effective in soups, bouillions, sauces and other applications with water in the finished product. "In some applications, a synergistic combination between MSG and other ingredients with sweet, umami and acid taste should be considered."

While some consumers report adverse reactions to MSGheadache, flushing, sweating, heart palpitations and nausea, among themresearch has not found a definitive link between MSG and what's referred to as MSG symptom complex. In a review of available literature on the relationship between MSG consumption and MSG system complex, including wheezing, welts, hives, migraine and stuffy nose, researchers concluded that decades of research have failed to demonstrate a clear and consistent relationship between MSG ingestion and the development of these conditions (Clinical & Experimental Allergy, 39:640646). Further, a 2009 study assessed whether blood pressure (BP) was associated with glutamic acid intake. The researchers found that the more dietary glutamic acid subjects consumed, the more their blood pressure fell, leading them to conclude: "Dietary glutamic acid may have independent BP-lowering effects, which may contribute to the inverse relation of vegetable protein to BP" (Circulation, 120:221-228).  Nevertheless, there are still a growing number of consumers looking for alternatives to the standard flavor enhancers.

With consumers demanding cleaner labels, natural alternatives fit into the equation more than ever, says Joe Leslie, national industrial sales & marketing manager, Kikkoman Sales USA, Inc., San Francisco. Companies with fermentation technology have met this need by creating new, all-natural products that provide umami and expand flavors, such as a new line of low-cost natural flavor enhancers that increase salt perception in foods without adding their own flavor to the end product. These can be used by themselves, or be part of a sodium-reduction systemoften partnering with potassium, he notes.

Its important to consider that some enhancers are not sodium-free. Yeast extracts act as flavor enhancers, but usually bring along some amount of sodium, cautions Jones. Yeast extract ranges from 2% sodium chloride (low-sodium versions) up to around 40% sodium chloride. HVPs also act as flavor enhancers, but typically have significant amounts of sodium. HVPs are typically about 40% sodium chloride. Anyone working with YEs or HVPs should check with the vendor for sodium chloride levels of the product.

Warsow keeps umami enhancers in his developers kit. The use of herbs and spices can be used to boost overall flavor without adding sodium, he says. This works especially well in processed meats. In various applications, he also suggests using organic acids, such as lactic, citric and malic, to fool the taste buds and boost the salty perception of a product.

Dried plum ingredients offer food processors opportunities to reduce the amount of added salt in formulations, without negatively impacting formula flavor objectives, while maximizing consumer flavor expectations, says James Degan, consultant, California Dried Plum Board, Sacramento, CA. This is because dried plums naturally contain 1.5% to 2.0% malic acid, an effective flavor enhancer. In bakery and meat applications, added salt can be reduced up to 25% when using dried plums.

Warsow says common American soups are among the most-difficult products when it comes to reducing sodium. We are all very familiar with the classic tastes of tomato soup, chicken noodle soup and minestrone soup, he says. Salt is a big flavor driver in all of these products. In the case of a minestrone soup, you can increase that herb profile by using a flavor that will boost and enhance the fresh herb notes in the product. You can also use an umami enhancer to boost the savoriness of the tomato base.

For Gascon, snacks are a big challenge because of the associated sensory phenomena. When you sample a salty snack, the amount of salt is topical. You will perceive it immediately, so your brain will turn down the volume on the salt message and you will taste less salt each time, he says. Traditionally, food developers have been forced to add heavy quantities of salt to assure that the intensity of the saltiness is great enough that even with the adaptation phenomena, you still will be able to taste the salt.

Because potassium chloride stimulates some of the same taste receptor cells as sodium chloride, its off-putting qualities are more pronounced in topical applications and can present flavor-modification difficulties.

Sometimes the perception of saltinessand the resulting level of salt neededcan be adjusted by the choice of salt used. According to Kragt, a finer salt will impart a rapidly sensed saline taste. Coarser salts deliver a slower, more-lingering saltiness. It is a good idea to consult with your salt supplier to learn about different salt options for specific applications.

One sodium-reduction solution comes via changing the structure of the salt granule. The crystals are created from a process that starts with a hollow pyramid shape, says Janice Johnson. This shape has a wide surface area and low bulk density that increases the rate at which the crystals dissolve. When these crystals touch the tongue, the rapid dissolution causes a flavor burst, allowing manufacturers to reduce the amount of salt while maintaining that salty flavor consumers desire. She notes that manufacturers, ingredient suppliers and researchers are diligently working on trying to create new sodium-reduction solutions. By working together, knowledge transfer from fundamental research to applications occurs more quickly and effectively, thereby resulting in more concrete solutions and better likelihood of commercial success, she says.

Yet even with an industry-wide effort, the biggest obstacle may be getting everyone on the same page at the same time. Can a population adapt at the same pace so that food processors dont lose consumers?

Salt perception is learned, says Jones. As consumers become accustomed to lower-salt products, old products are perceived as too salty.

Cindy Hazen, a 20-year veteran of the food industry, is a freelance writer based in Memphis, TN. She can be reached at [email protected].

Consumer Perception

A recent study from HealthFocus International (HFI), St. Petersburg, FL, revealed that, while nearly two-thirds (65%) of all consumers express some concern about sodium intake, 79% do not know the recommended daily intake level. Further, only 29% check the sodium content of the foods they buy. Further, the study found more than half of consumers (55%) reduce salt at the table, and nearly two-thirds believe sea salt (78%) is a healthier alternative. For the most part, consumers do know the types of foods that contribute significant amounts of sodiumfrench fries and other fast-food items, as well as processed meatsbut only one-third of them avoid such foods.

The NPD Group, Port Washington, NY, made similar findings. In its National Eating Trends report released in April 2010, the company notes a gap between consumers concerns about the amount of sodium in their diets and their actual consumption of low-sodium and sodium-free foods. Despite rising concern about sodium consumption, the number of people consuming low- or no-sodium foods has decreased.

 Rising Demand

According to a report from Packaged Facts, New York, Low- and No-Sodium Foods and Beverages in the U.S., the market for low-sodium/salt and no-sodium/salt products in the U.S. market reached $22 billion in 2009. Low-sodium/salt foods and beverages comprised $17 billion of the total, and no-sodium/salt products accounted for the remainder. The market research company believes that number will continue to rise as the quality of such products improves.