Technical Talk – June 2010

With Health Canada seeking to slash sodium from baked goods, we take a look at salt’s role and how it can be reduced or replaced.

With Health Canada seeking to slash sodium from baked goods, we take a look at salt’s role and how it can be reduced or replaced.

My April 2008 Technical Talk column dealt with salt and the implications of sodium in our diets. It discussed the role that salt plays in formulations and the difficulties of its reduction in processed foods. Two years later, the issue remains at the forefront of discussions concerning the future of the baking industry.

Health Canada, in consultation with the food industry, is targeting a reduction from the current consumption of 3,400 milligrams per person per day down to 2,300 milligrams by 2016. Efforts have been made by industry but greater reductions are needed to make progress toward minimizing the negative effects sodium has on human health.

Although there are some other natural sources of sodium, the majority of sodium in our diets comes from salt, which contains about 39 per cent sodium. The difficulty of salt reduction in foods relates to two major issues. First, humans have an inherent taste for salt and have been consuming salt for thousands of years. This makes it difficult for consumers to accept lower levels of salt in food products. Second, salt as a functional ingredient contributes to food safety and quality of food products. The role that salt plays in the production of baked goods was extensively discussed in the previous article but we will refer to it here.

Salt plays several crucial roles in bread making and production of other baked goods. First and foremost, it delivers and enhances taste in baked goods. Bread made without salt has a very bland taste. The absence of taste is not only due to the elimination of salt alone, but also due to the effect of its interaction with other ingredients in the formulation and enhancement of other flavours. For this reason, we often use salt in the formulation of sweet baked goods to enhance their sweetness.

As a functional ingredient in bread, salt strengthens the gluten by encouraging disulfide bonding, so the gluten holds more water and carbon dioxide, and the dough can expand without tearing. It may also reduce enzymatic degradation of gluten. In yeast-leavened baked goods, salt regulates the rate of yeast fermentation to produce a uniform product. It also controls wild yeast fermentation and reduces the growth of other microorganisms. Salt also plays a role in sugar caramelization, as it enhances crust colour.

While salt is critical to the success of our food system, there is still an opportunity to reduce the amounts used to a healthier level. As part of their health initiatives, many large food companies are targeting salt reduction. The major emphasis of these initiatives is focused on research and formulation changes. In addition to food companies, ingredient manufacturers have developed various salt replacers that claim to be effective at least in partial replacement of salt. The most common salt replacer is potassium chloride, and many efforts have been made to replace common salt (sodium chloride) with this ingredient in food formulations. Complete replacement using this ingredient is difficult because it imparts a metallic taste to the finished product. Some manufacturers introduced blends of mineral salts that have similar sensory characteristics to salt, no metallic potassium chloride aftertaste, and usage and handling similar salt. Other salts that can possibly, at least partially, replace sodium chloride include magnesium chloride, magnesium acetate and potassium gluconate.

Other low-sodium salt replacements are also on the market. These may include blends of sodium chloride with potassium chloride, magnesium sulphate and the amino acid L-lysine hydrochloride.

Simple and gradual reduction of salt can be achieved in food products without consumer awareness. This reduction will be minimal, to the extent that it does not affect the quality and safety of the food. Many of the alternatives can either replace or enhance the saltiness of foods. Some of these ingredients are derived from yeast, fungal and other proteins that are said to impart a salty taste without the addition of salt. They apparently have a synergistic effect with other flavour notes, so that a 50 per cent sodium reduction in biscuits and snack foods can be achieved. They are a natural source of ribonucleotides and glutamic acids, which enhance flavour.

As the salt has an effect on the functionality of gluten, especially in the formation of disulfide bonds, certain enzymes may play a role in substituting such a function. Enzymes are very efficient and have been utilized substantially by the baking industry. They have been instrumental in replacing functionalities of chemical ingredients such as potassium bromate.

A new enzyme, Transglutaminase, which forms bonds between amino acids in proteins and strengthens protein complexes, might assist in the reduction of salt in baked goods. The role of this enzyme in the reduction of salt in yeast-raised products still needs to be investigated. Recent research has focused on the size and shape of the salt crystal for the delivery of taste and functionality. By the reduction of the salt crystal size from 200 to 500 microns down to the five to 10 microns a U.K. company claims is possible, there is an enhancement of taste and functionality to the extent that a 50 per cent reduction of salt in baked goods can be achieved with no effect on taste and quality. Indeed, reduction of size to minute levels – the basis of nanotechnology – is beginning to be applied to various food ingredients in order to enhance functionality and flavour delivery.

Other sources contribute to the sodium content of baked goods; many chemical-leavening agents used in products such as cakes, muffins, and cookies contain sodium. Although the contribution of these agents to the sodium content of baked goods is low, efforts can be made to find alternatives. Often, the chemical-leavening systems are complex and their application is very specific, making it difficult to achieve the same results using alternatives. Some of these alternatives include zero-sodium leavening acids such as calcium acid pyrophosphate. This acid has a controlled release during the stages of baking, resulting in ideal volume and texture. Its carbon dioxide release profile is similar to other common leavening acids, and provides an additional source of calcium.

Efforts to reduce sodium in commercial food formulations are not easy due to the functionality and taste that salt contributes to the final product. The reduction is therefore not simple, but substantial research and development efforts are required.

Before venturing into replacements using other salts or commercially available replacers and enhancers, make sure of the regulatory status of these ingredients for domestic and export markets.

Dr. John Michaelides is Guelph Food Technology Institute’s director of research and technology. For more information, or fee-for-service help with product or process development needs, please contact GFTC at 519-821-1246 or  gftc@gftc.ca.