Let’s talk sodium and health first. We’ll get to the practicalities of chemical leavening next.

Scientists hotly debate the need to slash sodium intake across-the-board. It may not matter that the average American gets far more of this essential element than needed for proper functioning of the body, but for those suffering from high blood pressure, excess sodium intake can be life-threatening.

Of all dietary sources for sodium, baked foods bring a lot to the plate mostly due to their high frequency of consumption. That fact is unavoidable. There’s the salt in bread and the sodium naturally present in the flour, but there’s also the sodium contributed by baking soda and baking powder.

When bakers decide on a chemical leavening system, they most often pick leavening acids and bicarbonates that contain sodium for reasons of efficacy and cost. These leaveners are still the right choice for many baked foods. Yet, there’s a justifiable need for bakers to consider sodium content when working with new products or reformulating current ones.

“Over the past few years, government health agencies have recommended reduction of sodium in the diet,” said John Brodie, commercial development manager, Innophos Inc., Cranbury, NJ. “The baking industry has responded by examining ways to reduce sodium without compromising quality attributes that impact consumer perception of their products.”

Bakers are taking to this change, said Nita Livvix, R&D manager, Clabber Girl Corp., Terre Haute, IN. “Low-sodium and sodium-free leavening makes a lot of sense to the baker looking for ways to claim ‘reduced sodium’ for their baked products without compromising quality of texture, flavor or appearance,” she said.

Industry attention was cited by Bill McKeown, vice-president, innovation, AB Mauri North America, Chesterfield, MO. “We are seeing continued interest in our Baker’s Best low-sodium chemical leavening systems,” he said. “Customers are slowly but surely moving some of their production lines to lower sodium offerings for consumers.”

It’s still the content that counts. “It is important to know what levels of nutrients are in the finished product even if the ingredients are added at minor levels,” observed Steve Schorn, product development formulator, The Wright Group, Crowley, LA. “Whether the sodium, potassium or calcium levels are altered, the baking industry needs to keep their labels the public will view current and accurate.”

The nitty gritty

Chemical leavening must achieve certain things to do its job properly. It’s no different with low- and no-sodium systems. To work properly, the system requires a source of carbon dioxide (CO2) and a way to release it. Bicarbonates supply the gas, while food acids liberate it. Some formulas with acidic liquids (buttermilk, vinegar, fruit juice) can employ merely the bicarbonate (baking soda). Others require baking powders, a combination of bicarbonate and leavening acid activated by water and/or heat.

Double-acting baking powders start working in the batter when water is added and then release additional activity during baking. Encapsulation is another way to set up timed delivery of leavening. The choice of components depends on the end product desired.

“Chemical leavening is an acid-base reaction,” explained Sharon Book, PhD, senior food technologists, bakery, ICL Food Specialties, St. Louis. “Multiple factors can be considered when choosing among options for each component; sodium level is just one.” The same goes for the ingredients’ natural or organic status and the means of preparation from mixing through baking. The characteristics of the finished item — volume, texture, color, flavor — must be determined, too.

Two factors are significant to designing lower-sodium systems, according to Kristine V. Lukasik, PhD, director, applications, scientific and regulatory affairs, Food & Nutritional Ingredients, Balchem Corp., New Hampton, NY. First, the absolute solubility of phosphates in doughs and batters must be recognized in formulation. Second, the physical parameters affecting the leavening window — the period of time in which CO2 generation occurs — relate to other aspects of the dough matrix and its processing, such as the product’s shape and size, the length of the bake time and the strength of the gluten matrix.

Selection of the leavening agent, noted Mr. Brodie, requires knowledge of its neutralizing value (NV), its rate of reaction and its nutritional composition. NV, sometimes called strength, determines the amount of leavening acid required to react with the bicarbonate. The rate of reaction guides the formulator in choosing the best acid(s) for the job, and knowledge of the composition enables addition of positive nutrients and subtraction of negative ones.

By adjusting the choice of acid and the amount of bicarbonate, the formulator can achieve significantly release rates and times, Mr. McKeown observed. “Bench tolerance can be adjusted to fit a specific bakery process so that end product attributes are achieved,” he said.

Formulas in flux

Interest in sodium-free leavening bases has increased, according to Judy Underwood, product manager, Performance Products Group, Church & Dwight, Princeton, NJ. Switching out of sodium bicarbonate enables this adjustment. “Our ammonium and potassium bicarbonates behave conventionally and for many formulations are direct replacements when adjusted for differences in neutralizing value,” she said.

Ms. Underwood identified the company’s Flow K Potassium Bromates as a replacement for standard sodium bicarbonate, adjusted for differences in neutralizing values. “Additionally, ammonium bicarbonate can be a good non-sodium alternative in certain formulations and may offer opportunities for potential clean-label advantages,” she noted.

Potassium bicarbonate has emerged as the alternate to baking soda, agreed Dinnie Jordan, director, Kudos Blends Ltd., Cleobury Mortimer, UK. She explained, “[With it], there is no need to reduce salt levels or remove the highly functional sodium acid pyrophosphate (SAPP) to achieve a significant sodium reduction. Potassium bicarbonate is the simplest and easiest way to reduce sodium while maintaining key product characteristics such as taste, texture or volume. And by removing a small amount of the added salt, it can be used to achieve up to a 50% reduction in sodium.”

Some bakers prefer to shift the leavening acid rather than the bicarbonate because of concerns about taste, according to Mr. McKeown. “As a result, there has been movement to use calcium phosphates instead of ­sodium-based phosphates as leavening acids and to keep some or all of the sodium bicarbonate in the leavening system,” he said.

Today, the typical formula for a chemically leavened bakery product uses SAPP or sodium aluminum phosphate (SALP) in combination with monocalcium phosphate (MCP) and, possibly, dicalcium phosphate dehydrate (DCP), Mr. Brodie said. “SAPP is the most widely used leavening acid on a global basis,” he added.

He detailed the sodium contribution in bakery formulas. Nearly 99% of sodium comes from three components: salt, sodium bicarbonate and the leavening acid. Per 100 g, salt contributes 39,000 mg sodium, SAPP 21,000 mg and sodium bicarbonate 27,000 mg.

SALP, however, comes in 10 times lower in sodium, and Mr. Brodie observed that Innophos’ Levair SALP contains 2,100 mg sodium per 100 g while the same weight of its Activ-8 blend of SALP and MCP carries only 1,350 mg sodium. Innophos’ Cal-Rise calcium acid pyrophosphate (CAPP) and MCP is a completely sodium-free choice carrying the same NV of 72 as SAPP. He reported that its use cuts the leavening system’s sodium contribution by as much as 25%.

Ultimately, the formulator wants to achieve optimum nucleation, or the creation of the gas bubbles that leaven the product. This needs to be done during mixing. “MCP has always been a no-sodium option for this function,” Dr. Book explained. “Conversely, if a late expansion of the muffin or cake batter during baking is desired, again the only option is a no-sodium DCP.”

The conversion question

Projects in the low-sodium chemically leavened baked goods category start the same way as most: by deciding the type of product to be made (cakes, muffins, biscuits, pancakes), the format (fresh-baked, frozen, dry mix) and the end user or baker (wholesale bakery, foodservice, consumer). The standard leavening acid for existing products will be SAPP or SALP, but to cut sodium, the formulator can turn to calcium-based ingredients.

“Existing formulas can be switched to calcium-based leavening systems with no noticeable change in characteristics when formulating for sodium reduction,” Mr. Brodie said.

Such systems are not just for reduced-sodium baked goods. “The calcium salts like Cal-Rise provide other functional performance advantages,” he added. These include improved cake crumb, clean flavor profile, increased dough development and improved product resiliency.

Processing needs must also be considered. “For example,” Dr. Book said, “if a batter requires refrigerated storage, the heat-activated leavening acids contain sodium. However, if the wet and dry ingredients are mixed and baked in a relatively short period of time, there are more choices.” ICL developed its CAPP, trademarked Levona, with different grades and reaction rates like those of SAPP.

“Sodium and calcium do affect the texture of products differently,” Dr. Book continued. “It is not a simple replacement of one ingredient for another. The anion choices are sodium, calcium or aluminum; there are no potassium-based leavening acids.”

Regulatory issues also affect conversion. Earlier this year, EU authorities banned use of SALP in all bakery items except a single niche product: Battenburg-style sponge cakes. Ms. Jordan described the development of Kudos SALP Replacer, a zero-aluminum acidulant that substitutes in process tolerance for the popular SALP. “The US and Australia have already expressed interest in SALP replacers, and trends to eliminate SALP are expected to continue across the globe,” she said.

SAPP is also at issue, Ms. Jordan added, because it includes minute amounts of aluminum. Kudos developed its Opus range of phosphate blends to mimic SAPP but at the legislated lower aluminum levels.

Dr. Lukasik confirmed the choices being made. “There has been a mass exodus from systems that include SALP, particularly in Europe, where recent regulations forced the matter,” she noted, adding, “There has been a push for simpler ingredient declarations, including ‘free from’ claims.”

Now, make it work

As every formulator knows, there’s a difference between theory and practice. “Leavening is perhaps as much of an art as it is a science,” Dr. Lukasik observed. “Leavening agents are easily exchangeable on paper but less so in practice. One-for-one substitutions are sometimes not straightforward.”

Give the starting formula a critical eye, Dr. Lukasik recommended. Ask the question, where does most of the sodium originate, from salt or from leavening? “When it’s from salt, that’s the obvious first target,” she said. “Salt flavor modifiers, such as our choline chloride-based C-Salt, can be used to improve sensory impact of remaining sodium chloride. When it’s from the leavening, identify the main contributor. Typically, this will be sodium bicarbonate and/or SAPP.”

Matters get more complex as formulation work proceeds, according to Jesse Weilert, manager of bakery applications, Corbion Caravan, Lenexa, KS. There’s the question of how to best get to the needed sodium reduction. Modest cuts of up to 20% can be achieved by adjusting the levels of salt and the existing leavening system. “However, when more aggressive reductions are required, the use of low-sodium components become necessary to keep product quality in line with the current offering,” he said.

“Improved technology is making it easier to convert from traditional systems to these low-sodium components, but care still needs to be taken to ensure process, product and shelf-life performance are not jeopardized,” Mr. Weilert noted.

Formulators can adjust components individually by taking into account their rates of reaction and neutralizing values to provide the needed gassing power and proper time of gas generation. “It is less complex to use baking powders that have been designed with low sodium in mind,” Mr. Weilert said. Corbion Caravan’s Low Sodium Baking Powder is balanced to give functionality similar to the higher-sodium counterparts.

The same goes for double-acting systems. Ms. Livvix explained that Clabber Girl’s InnovaFree Sodium Free baking powder offers the balance of leavening powder of conventional double-acting systems. “It’s as simple as substituting these ingredients on a 1:1 ratio for the original baking powder being used,” she said.

Like many formulation changes intended to enhance the healthy image of foods, replacement of sodium-bearing leavening systems can become a matter of affordability. “One always needs to keep cost in mind,” Dr. Book noted. “Each leavening acid differs in the optimum amount used with the base, so cost and use level can also be considered into the decision making process.”

Economics of use matter, too. “Of the healthier options being built into formulas these days, sodium reduction has particularly high cost hurdles,” Mr. Weilert said. “This cost makes industry-wide sodium reduction challenging from a financial perspective and has led to adopting low-sodium approaches [only] when customers, laws and sales potential drive the decision process.

“The decision to use a low-sodium approach versus a traditional formula is driven by the needs of the customer and the potential value that this style of product provides,” he summarized.