Taste Physiology of Sweeteners

Originally Published: November 12, 2014
Last Updated: February 11, 2021
This bubbling, carbonated softdrink acts as a trigeminal pain agent, a sensory affect that reportedly acts on high-potentcy sweeteners, resulting in a more sugar-like effect.

November 12, 2014 – When it comes to making foods sweeter in a “clean label way,” there are ways to do it naturally and simply, besides using sugar. Some approaches take advantage of the connection between taste and smell, thereby employing considerations and taste physiology of sweeteners. The trigeminal nerve is found in the face (rather than the nose). It responds to irritants, like tingling and numbing, as well as temperature differences.

“The trigeminal sensation can also be used for sweetness enhancement, as can all of the other senses,” said Alex Woo, Managing Director of W2O Food Innovation, as he discussed recent technologies in clean labeling sweetness enhancement.

Natural high-potency sweeteners, such as stevia and monk fruit extract, offer solutions in reduced-sugar or sugar-free applications. When using these sweeteners, a bulk sweetener is also sometimes needed, such as natural non-/low-caloric erythritol, which helps achieve maximum sweetness, yet with minimal off-flavors and low cost, suggested Woo.

Alex Woo discusses sweetness enhancement and how the brain processes taste.

Cross-modal correspondence can enhance sweetness. The brain processes information from different
senses to form multisensory experiences. For example, smells, other tastes, trigeminal sensations, sights (like colors) and sound all influence taste.

Stevia extract, which is labeled as such, is commonly used and has multiple suppliers. It is “natural,” non-caloric, has GRAS status with no FDA objection letter, is 200-400 times sweeter than sugar, stable to heat and a pH over 3, is non-GMO; and certifications for kosher and halal are available. Monk Fruit extract is also non-caloric and is GRAS with no FDA objection letter. It is not yet approved in the EU. Monk fruit extract, not quite as common yet, is 150-200 times sweeter than sugar, heat-stable, non-GMO, kosher-certified and is labeled as “monk fruit extract.”

“Monatin” is a unique, natural amino acid that has recently emerged, but, as yet, is not approved anywhere. It is extracted from a South African plant, Sclerochiton ilicifolius root. It is 3,000 times sweeter than sugar with a unique temporal profile. Monatin has a quick sweetness on-set and no lingering, bitter, metallic or astringent aftertaste.

Woo went on to explain that erythritol has multiple suppliers, is found in fruits and vegetables, and is the only natural polyol made by fermentation. It also has the highest digestive tolerance among all polyols. Non-caloric, it is non-GMO-possible, 65% as sweet as sugar and has a 3.5% limit in beverages in the U.S. However, not all consider erythritol a clean label solution.

“When ‘natural’ is not enough,” Woo gave examples for sweetener enhancement that could result in shorter label declarations. He explained how to use “cross-modal correspondences” to enhance sweetness. The brain processes information from different senses to form multisensory experiences in people’s daily lives; therefore, smell, tastes other than sweetness, sights, sounds and trigeminal sensations can all influence the perception of sweetness.

Although sweetness is detected in the mouth, there is also interaction between olfaction and gustation. Retronasal “sweet” aromas sensed in the nose increase the sweet perception in the mouth. Many sweet taste modulators are legally labeled as “natural flavors,” thus result in more consumer-friendly labels.

Woo referenced work by Professor Tepper at Rutgers University, who is investigating molecular biology as a way to “trick” the taste buds. “This approach is novel in the food industry,” stated Woo, “but it is the way of the future.” For example, fresh tomato aroma makes tomato sauce taste sweeter. Sugar distillates enhance beverage sweetness.

Vanilla, below and above threshold, enhances sweetness, according to various reports. Some FDA GRAS, natural, high-potency sweeteners are approved under FEMA GRAS as “natural flavor,” when they are used at very low levels, as sweetness and/or flavor enhancers. Examples include thaumatin and monk fruit extract. Woo explained trigeminal-on-taste “intramodal” sweetness enhancement using the examples of carbonation, a trigeminal pain agent, which can make artificial high-potency sweeteners taste more like sugar. It is labeled as “carbonated water.”

Beverages formulated with high-potency sweeteners have also shown in panels to taste sweeter at higher temperatures. Some studies have shown that the shape of a food, specifically a more rounded shape—as in oranges or apples—tends to be associated with sweeter stimuli. For example, round chocolates were found to taste sweeter than other shapes.

Research has found that color influences sweetness, as well. Strawberry mousse was sweeter and more liked on a white plate than on a black plate. Hot chocolate tasted sweeter and had more aroma in a dark cream cup than in a white or red cup–“Why? I don’t know,” smiled Woo.

Clean label, reduced-sugar foods and beverages with high-potency and bulk sweeteners can be made even sweeter with cross-modal correspondences. Woo concluded: “As Ernest Starling, 1866–1927, Nobel Prize winner and discoverer of the first hormone put it: ‘The physiology of today is the medicine of tomorrow.’”

Alex Woo, Ph.D., Managing Director and Founder, W2O Food Innovation, Alex.Woo123@gmail.com, +1.425.985.8168, http://tinyurl.com/alex-woo-w2o

November 12, 2014, Global Food Forums — The summary above is an excerpt from the Ingredion-sponsored “2013 Clean Label Conference Magazine.”