Chef David Kamen Presents Research Results on Strategies for Reducing Sodium in Foods

At the recent Worlds of Healthy Flavors Conference, co-produced by The CIA and Harvard School of Public Health, Culinary Professor David Kamen presented research results from an MRFDI project investigating strategies for reducing sodium in foods. Collaborating with Dr. Chris Loss, Kamen combined sensory science and culinary arts techniques to design and conduct experiments that explored the effects of different types of salts on consumers' overall liking and perceived saltiness of common foods, including chicken broth, mashed potatoes, and bratwurst sausage. Their work demonstrates that when objective evidence-based methods are used, sodium reductions of as much as 34% can be achieved.

Attendees listen as Chef Kamen describes his research.

Chef Kamen began his presentation by offering the packed audience in the Ecolab theater a taste of his sensory evaluation testing procedures. Each of the conference attendees received 4 variations of a traditional bratwurst recipe:

1. using kosher salt
2. using 25% less kosher salt
3. using high quality sea salt
4. using a sea salt that is naturally lower in sodium (by approx 30%)

The samples were presented in cups labeled with random 3-digit codes, and the order of presentation was randomized to prevent "order bias" and allow for meaningful statistical analysis of the results.

Chef Kamen presents his research on salt reduction.

Kamen and Loss introduced the audience to one of the major workhorses of the field of sensory testing known as "ranking tests." This test is commonly used in the food industry to determine if there are actual perceived differences between food products. (View additional information on sensory evaluation techniques.) The panelists (in this case the conference audience) were asked to taste the bratwurst samples in a specified order and to rank them first based on "overall liking," and then again on "perceived saltiness." View examples of the tasting ballots.

Statistical analysis of the data showed that, based on overall liking, conference attendees could not distinguish between bratwurst samples seasoned with typical levels of kosher salt (equivalent to 226 mg Na /ounce of sausage) and those with 25% less (equivalent to 175 mg/ ounce of sausage). They could distinguish the samples based on their perception of saltiness, however. Interestingly, the audience preferred the bratwurst samples seasoned with standard sea salt, but liked least the sample that was seasoned with sea salt that contained naturally low levels of sodium. The results can be represented like this:

Liking (#1= most liked; #4 = least liked):

#1 = sea salt^a
#2 = kosher salt^b
#3 = 25% reduced kosher salt^bc
#4 = naturally low sodium sea salt^c

Perceived saltiness (#1= most salty; #4 = least salty):

#1 = sea salt^a
#2 = kosher salt^a
#3 = naturally low sodium sea salt^b
#4 = 25% reduced kosher salt^b

Samples with different superscripts are significantly different (p

This engaging and informative start to the presentation had the audience focused on objective evaluation of flavors and considering their personal preferences and perceptions of saltiness in a meat-based product.

Common culinary salts. From left: Kosher, Baleine Sel de Mer, Fleur de sel, Sel Gris, reduced Na Sea salt.

Kamen continued his presentation providing a background on salt production and usage in the US, a review of previous research related to sodium production, and a summary of the trends in the food service industry related to salts. This lead into a detailed description of the methodology he used to measure liking and perceived saltiness in mashed potatoes and chicken broth.

Some of the more interesting results showed that when kosher salt was used to season mashed potatoes, there was a detection threshold at 50% reduction. However, at 34% reduction, people could not detect any differences in saltiness. Kamen suggested that his results indicate that sodium could be reduced incrementally without perceived differences. Ranked preference tests for the same samples showed that there were two preference populations for mashed potatoes: one that liked low levels of sodium and one that liked high levels. Kamen made an interesting observation, pointing out that the panelists that preferred higher levels of sodium had fewer years of professional culinary experience. Kamen posited that this was because an understanding of flavor, which is a multi-sensory experience, is gained by practical hands-on experiences with seasoning of foods. There are interesting implications that a trained palate is better prepared for designing lower sodium products. Perhaps this is why we are seeing more and more chefs getting involved in the product development process.

Kamen continued his presentation by showing that the effects of different culinary salts on perceived saltiness and overall liking depended upon the food matrix being seasoned. For example, panelists could not perceive any differences in saltiness in chicken broth seasoned with baline sel de mer, kosher salt, and sel gris. However, when seasoning mashed potatoes, kosher and baline sel de mer were perceived to be more salty than sel gris. The following figure provides details on the mineral profiles of the salts used in Kamen's study.

Mineral composition of common culinary salts

Kamen pointed out that factors other than saltiness can impact preference. This seemingly obvious conclusion is often overlooked in the "debate" of sodium reduction. Understanding culinary intricacies of flavor, or "multi-modality" as sensory scientists would refer to it, can help product developers redesign products that minimize sodium without compromising flavor. Chef Almir DaFonseca put it another way at an NRA conference in 2008 by pointing out that chefs shouldn't use salt as a "crutch" to make up for laziness in the kitchen, and that "Salt is not a flavor profile in and of itself, it is a component of the taste, texture, complexity, and depth of a dish."

Chef Kamen also noted that the sea salts, which are often highly priced, do not necessarily make it easier to lower sodium in foods, which is a common belief amongst many chefs.

Kamen concluded his talk by sharing the following strategies for reducing sodium:

• Reduce salt incrementally, and on a dish by dish basis
• Inclusion of additional flavor profiles may allow for the decreased usage of salt
• Season at the end of preparation to avoid adaptation to salt
• Take into account the inherent salt in your ingredients
• Incorporate whole fruits and vegetables into dishes as they generally contain lower sodium levels than meats and ready to eat foods
• Reduce portion size

Chef Kamen and Dr. Loss are currently working on additional sensory tests in the area of sodium reduction and are preparing a manuscript for publication that will share their results with the rest of the culinary field.

For more information on this work you can contact Chef David Kamen or Dr. Chris Loss.