Sodium Reduction: A Grain of Salt
July 1, 2011
by Rebeca López-García
Sodium reduction has been a hot topic for a long time, but with recently published data linking a high-sodium diet with several health problems, this formulating concern is going back in the oven. In 2006, the American Heart Association (AHA) asked food manufacturers to reduce the amount of sodium in foods by 50% over a 10-year period, and the American Medical Association called for the food and restaurant industries to lower the sodium levels in the US food supply by 50%. So is there a good reason to comply with these recommendations?
Sodium plays an essential role in health and well-being. Human bodies indisputably need salt to function, a fact pointed out by Marina Hahn, junior product manager, specialties, Jungbunzlauer Ladenburg GmbH, Ladenburg, Germany. Sodium is the main component of the body’s extracellular fluids and helps carry nutrients into our cells. It also helps regulate other body functions such as blood pressure. We cannot exist without sodium, but the amount we need is rather small, and years of research have shown that diets high in sodium increase the risk of hypertension. According to the Centers for Disease Control and Prevention (CDC) and the US Department of Agriculture (USDA)’s 2010 Dietary Guidelines for Americans (DGA), adults should consume no more than 2,300 mg of sodium per day, which is far lower than the amount most Americans currently get. For those 51 years and older or who have hypertension, diabetes or chronic kidney disease, daily intake of sodium should be limited to 1,500 mg, and most experts have pinpointed the Dietary Approaches to Stopping Hypertension (DASH) diet as an ideal eating pattern to help reduce blood pressure.
Although a common belief states that sodium intake can be greatly reduced by hiding the salt shaker at home, in reality, more than 70% of sodium intake in the modern diet comes from processed foods. According to Barbara Heidolph, principal, marketing technical service, ICL Performance Products, St. Louis, MO, grain-based products account for 36.9% of daily sodium intake. The 2010 DGA and the April 2010 Institute of Medicine report “Strategies to Reduce Sodium Intake in the United States” identify yeast breads as the largest single food contributor to daily sodium intake, accounting for 7.2% of the total. (Download a list of sodium-containing compounds used in processed foods
On the other hand, Elizabeth Arndt, director of R&D, ConAgra Mills, Omaha, NE, said that one of the two overarching concepts in the 2010 DGA is that Americans should focus on consuming more nutrient-dense foods such as whole grains while reducing food components such as sodium. Thus, opportunities abound for bakery products with healthier formulations that reduce sodium. However, this may be easier said than done since sodium plays a crucial role not only in the sensory profile of baked goods but also in functionality.
One of the first steps to consider is to understand the food system involved and the role sodium plays. The second step is to identify all sources of sodium in the product. Salt (sodium chloride) may be the first choice for reduction, but there may be many other ingredients and additives that contribute to the total sodium content in the product.
According to Ms. Arndt, salt not only acts as a flavor enhancer in yeast breads but also plays an important role in the functionality of the dough, affecting both the manufacturing process and finished product attributes. In yeast bread products, salt is traditionally used at about 2% (flour weight basis). Salt lowers yeast activity, which can help control the fermentation process and proof time. Salt also lengthens the mixing time needed for gluten development and strengthens the gluten matrix. In the final bread products, the formula salt affects the flavor as well as other important attributes such as the product volume, crumb appearance and texture.
According to a report by Donald Dubois, Doris Blockcolsky and Patrick Dreese of the American Institute of Baking (AIB), Manhattan, KS, it is common knowledge that the addition of salt to a bread dough extends the mixing time required to develop the dough fully, and this is why many bakers use the delayed-salt method in commercial dough baking. The researchers studied the impact of salt on dough development. They found that reducing salt levels to as low as 1.8% helped not only achieve sodium reduction but also save energy through shorter mixing time while obtaining bread of good quality.
However, because sodium acts to strengthen gluten, sodium reduction decreases dough resistance and induces dough stickiness. To address this issue, The Netherlands-based food research organization TNO developed Reuteran, an α1-4, α1-6 glucan produced by lactic acid bacteria, Lactobacillus reuterii
, that acts synergistically with gluten to strengthen it. Addition of 2% Reuteran (flour weight basis) restores the bread volume lost when reducing salt by more than 50%. It helps overcome dough weakness and stickiness resulting from salt reduction without introducing buckiness or stiffness.
Ms. Arndt described ConAgra Mills’ consumer sensory studies on 100% whole-wheat bread made with different levels of formula salt. Researchers found no difference in overall product acceptability or salt perception between breads made with 1.5% or 2% salt. Thus, it appears that salt can be lowered by as much as 25% in whole-grain yeast bread formulas with little to no detection by consumers. This level of salt reduction is expected to have little impact on production.
In chemically leavened grain-based products, including muffins, cookies, quick breads and pancakes, the main sources of sodium are salt and the chemical leavening system. Salt functions primarily as a flavor enhancer, and leavening systems traditionally use sodium bicarbonate in combination with leavening acids such as sodium acid pyrophosphate (SAPP) and sodium aluminum phosphate (SALP).
According to information from Clabber Girl, Terre Haute, IN, up to 50% of the sodium in chemically leavened bakery products can come from the baking powder. The sodium in these products can be replaced with other ingredients such as reduced-sodium and sodium-free baking powders that use calcium.
Cranbury, NJ-based Innophos supplies calcium-based leavening acids that can replace the usual sodium-based acids in conventional baking powder without affecting the process or product profile. Calcium-based leavening systems include blends of calcium acid pyrophosphate (CAPP) and monocalcium phosphate (MCP) and remove the guess work in formulation since replacement can be done on a 1:1 basis, and substitution can lead to sodium reduction of as much as 25%.
One of the major problems associated with reducing sodium in baked products is overcoming the sensory problems associated with taking away salt. Reducing salt on its own will not help bakers achieve their goals since a baker can only remove so much salt before the product loses its consumer appeal. Therefore, it is important to consider compounds that will help replace the flavor lost by sodium elimination. This is not an easy task since, according to a report published in the January-February 2011 issue of Cereal Foods World
, saltiness is perceived via permeation of sodium ions through an ion channel in cell membranes of the tongue. This mechanism is quite specific, and besides sodium, the only nontoxic ion that permeates this channel is potassium.
The use of potassium chloride is perhaps the most common strategy to replace salt. Replacing up to 20% of sodium with potassium results in bread with an acceptable taste; however, further replacement is limited due to unacceptable off-flavors.
Some taste enhancers added to blends include glutamate, but this compound may contribute a strong yeast taste or unpleasant color. Other blends use sodium gluconate, potassium chloride and sodium chloride, which can help achieve up to a 50% sodium reduction without affecting the sensory profile, crumb texture and browning of the finished product. The addition of calcium-based leavening agents also helps boost the calcium content of the product and can enable a “good source of calcium” label claim.
Also, the DASH diet recommends foods rich in magnesium since this mineral also plays a role in maintaining healthy blood pressure. This can be achieved using some of the salt substitute formulations in the market. Another important consideration, however, is cost because many salt replacers are significantly more expensive.
STRIKING A BALANCE.
Sodium reduction is here to stay, and many companies have pledged to reduce the sodium content of their products to help fight the battle of chronic degenerative diseases. However, salts play essential, functional roles in baked products and, more importantly, in consumer preferences. Consumers expect the rich flavor of products currently in the market. Thus, sodium reduction should be taken with a grain of salt when considering gradual stepwise cuts to achieve the final reduction goal without compromising consumer preference.