Sodium Reduction Using Taste Modulation
When the quest for health combines with a pursuit of clean labels, the resulting formulation challenge means both emerging and underutilized traditional solutions should be considered. Alex Woo, Ph.D., CEO, W2O Food Innovation, set out to explore clean label sodium reduction at the 2022 Clean Label Conference. Woo provided updates on the rapidly changing field of taste perception and offered innovative approaches to reducing salt in his presentation titled “Sodium Reduction: Using Clean Label Salty, Umami and Kokumi Taste Modulation.”
“Flavor,’’ Woo explained, “is our reaction to the food in front of us.” It involves all five senses:
- Taste, of which there are five, including both salty and umami
- Smell (aroma)
- Somatosensation (touch), i.e., temperature, pain and spiciness
Neuroscience has made significant advances in understanding how humans perceive taste. For example, “Some 40 taste receptors have been found in the mouth in the past 20 years,” said Woo. Bitterness receptors account for 25 of them. In humans, there also could be fat, calcium and water receptors.
A “starchy” receptor was proposed in 2016. Sweetness, umami and saltiness each have one type of receptor. However, the story is more complex than receptors. A secondary pathway for sweetness perception and another pathway for saltiness that responds to high levels of NaCl and any level of KCl have been discovered.
There are four strategies to reduce sodium, noted Woo. The first is salt substitution with substances less salty than sodium chloride (e.g., potassium chloride [KCl] to replace table salt [NaC]). The second is the increased surface area of NaCl structures, such as the formations of microspheres. The use of umami-tasting ingredients is the third strategy. Fourth, neuroscience (e.g., expectancy constancy) can be utilized.
Woo spent much time discussing how to use umami taste for saltiness modulation. He suggested it is the most important, easiest and most under-utilized method in sodium reduction. There has been much research in this area in the last three to five years.
How to Increase Umami Directly and Saltiness Indirectly
Adding umami ingredients increases saltiness disproportionately more than expected from the minimal amount of sodium that might be added. The interactive effect of salty and umami tastes is based on a neuroscience concept called prior association. Over time, the mind learns that an umami taste will also be present when saltiness is tasted in a food such as prosciutto. Eventually, the umami taste triggers an associated increase in saltiness. “There are reports that by adding mushroom extract, or even the mere mention of a mushroom extract, increased the acceptance of a low-sodium burger,” said Woo.
The use of monosodium glutamate (MSG) is a traditional tactic to increase umami. MSG is made by fermenting crops like corn, sugar cane or cassava. MSG has one-third that of the sodium of NaCl, by weight (i.e., 12% vs. 40%). A blend of 33% MSG and 66% NaCl (by weight) will equal a 25% reduction in sodium but not saltiness.
Many clean label alternatives to pure MSG can be found in nature. They include yeast extracts, hydrolyzed vegetable proteins, soy sauce, fish sauce, and chicken and beef broth. All are naturally high in MSG (or, when in solution, co-exist with the free amino acid glutamic acid) and nucleotides.
Some alternatives labeled “vegetable extracts” have naturally high glutamate (MSG) levels and nucleotides for enhanced umami. Mushrooms are perhaps the most universal flavor with the least amount of off-flavor, advised Woo. High umami extracts, like seaweed and sake lees (aka sake kasu) work well with congruent Asian flavors. However, due to their inherent flavors, they can only be used in low dosages or in foods with flavors that go together well.
Certain food components also significantly enhance the umami taste. For example, savory dishes with tomato (which contains about 0.3% MSG), corn (contains about 0.6% MSG), Cheddar cheese (about 6% MSG) or Parmesan (8% MSG) are often found to be deliciously savory.
Enhancing the Umami Taste
In his presentation, Woo talked about boosting, rather than adding, umami tastes in a food through Positive Allosteric Modulator (PAM) molecules. MSG is “trapped” by the T1R1 taste receptor, a concept similar to how the Venus Fly Trap (VFT) plant traps flies.
MSG is bound inside the T1R1 VFT receptor, while PAM molecules bind near the outside of T1R1 VFT receptors. This results in a more tightly bound MSG, which is 4-to-8 times more potent.
Nucleotides IMP+GMP, traditionally called MSG potentiators, have recently proven to be PAM. They bind next to or at the allosteric site where MSG is bound, stabilizing the closed VFT conformation. This increases how tightly MSG is bound and makes it more potent. Both can be argued to be a “clean-er” label than adding pure salt and pure MSG, noted Woo.
Much research is taking place in the area of umami peptides, which may be PAMs. Some have been isolated from fermented Asian foods; some are Maillard reacted peptides. They have not yet been commercialized. They could be labeled as natural flavor, if made by precision fermentation in the future.
Sodium Reduction Using Clean Label Salty, Umami and Kokumi Taste Modulation, by Alex Woo, Ph.D., CEO, and Founder, W2O Food Innovation.
To view a pdf of the presentation, go to Clean Label Sodium Reduction in Global Food Forums’ R&D Academy.