Although its been a few years since I've been in the flavor applications lab, flavor suppliers tell me that some things haven't changed. Food product developers still want a flavor to magically transform a poor-tasting base into a palate-pleasing product. However, understanding the nature of the ingredients in the base and their interactions, as well as knowing the source and type of undesirable flavor notes present, goes a long way toward creating pleasant-tasting foods and beverages.

Flavors are expected to provide a characteristic flavor, as well as cover undesirable base notes. Flavor companies take a multi-functional approach to solving these flavor challenges by using masking agents in combination with flavoring ingredients. Flavors that provide physical and/or chemical properties are the next generation of flavor compounds.

The Great Cover Up

While masking agents cover up undesirable notes in a wide variety of applications, flavor companies spend the most time covering up flavors/attributes such as bitterness, vitamin and mineral flavors, soy notes, nutraceutical flavors, glycerin flavor, metallic notes, chemical burn from preservatives, and warmed-over flavor (WOF) in meats and coffee.

Masking bitterness is perhaps the number one candidate for taste modifiers. Many ingredients cause bitter notes to develop, including artificial sweeteners, botanicals, preservatives, caffeine, glycerin, and grapefruit juice/extract. Bitterness is caused by naturally occurring bitter compounds, or through chemical reactions during storage or processing. Adding sugar helps, but may not be an option, particularly for diet products.

"The bitter, burning chemical notes of glycerin, especially at higher levels, can be especially troublesome," says Kim Gray, Ph.D., senior scientist at WILD Flavors, Inc., Cincinnati, Ohio.

"Glycerin's sweet notes are a positive for confectionery applications, but can be a negative for savory applications. Using masking agents in combination with characterizing flavors works well in glycerin-based applications."

WILD recently developed flavors based on technology that "covers" the taste buds so consumers are not able to perceive undesirable notes. "Instead of overloading the taste buds with a heavy flavor, we are really tricking the taste buds into not perceiving the off note," says Gray. "We believe that the blocking compound masks undesirable notes by occupying part of the receptor, however, it can also suppress some of the characterizing flavor notes. We have to be careful with the usage level, depending upon the particular application, and rebalance the flavor portion accordingly."

"We receive lots of requests to reduce the bitterness of grapefruit products," says John Cavallo, Ph.D., vice president of the Beverage Business Unit at Haarmann & Reimer Corp., Teterboro, NJ. "We have found ways to use flavors and modify the profile of grapefruit to make it more appealing for children. Bitterness masking agents can help solve these types of bitterness problems."

While processors of soy ingredients have made great strides toward reducing undesirable beany, green, cereal-type notes from soy, flavor suppliers still spend a good bit of time answering requests to mask these notes from soy isolates, concentrates and other soy ingredients. Many suppliers are introducing lines of soy masking agents specifically for this purpose.

Flavor Solutions

The following is a list of solutions to common flavor problems that food formulators encounter when trying to flavor products with undesirable flavors:

• Provide base product. Provide your supplier with an unflavored food or beverage base whenever possible. "While we can guess on the usage level, it is always best to work with the customer's base and optimize the flavor character and usage level up front," says Gray.
• Cover unwanted notes first. Suppliers recommend covering up odd base notes first. While some customers are willing to do this, some are not, according to suppliers. "We are trying to communicate that masking is very important," says Maureen Draganchuk, vice president of Business Development for Virginia Dare, Brooklyn, NY. "We advise covering the undesirable notes first and optimizing the base, before adding the characterizing flavor."
• Do not "over flavor" products. "If a little is good, more is better." Many food formulators are still using this incorrect approach to flavor their products. Flavors are designed to be used at a certain strength that, when exceeded becomes imbalanced, resulting in chemical burn and unwanted tastes.

"We recently solved a flavor problem in an over-flavored, soy-based vanilla dessert by reducing the amount of vanilla and adding a masking agent that greatly smoothed the base," says Draganchuk. "The customer was expecting the vanilla flavor to both flavor the system and cover up the beany-cereal notes of soy."

• Go beyond vanilla and chocolate. Vanilla and chocolate are two of America's favorite flavor profiles. However, with many of the soy-based or nutraceutical products entering the mainstream marketplace, these flavors may not be best suited to the product.

Draganchuk recommends trying more fanciful flavors--such as maple walnut or chocolate orange--for sweet soy-based products, for example. "If you create something that has a different expectation, your chances of marketplace success will be greater. Flavor your product smartly."

"We have had the best success building flavor profiles off of the inherent notes in the base products," says Cavallo. "You have to work with your base rather than against it." This means that if your base develops a cereal note, add something that compliments that particular flavor (such as nutty or brown notes).

Future Flavors

Each year, flavor companies are learning more about how to address unwanted flavors. New technology has evolved from necessity.

"You can't sit still with a line of masking flavors," says Draganchuk. "You have to understand how the industry is changing so you can predict the industry's needs to stay in the forefront," she adds. "We listen carefully to what customers tell us about their needs. There are a lot of new materials that we can take advantage of to give customers what they are looking for." PF

What we perceive as flavor is a combination of what we taste on our tongues and mostly what we smell. The five recognized tastes are sweet, salty, bitter, sour, and umami (MSG taste). By identifying taste bud receptors, independent of olfaction, researchers recently identified a sweet receptor and receptors for umami and bitterness.

Linda Buck, Ph.D., professor of neurobiology, and colleagues at the Howard Hughes Medical Institute, Dept of Neurobiology, Harvard Medical School, Boston, Mass., published a paper in the May issue of Nature Neuroscience (Vol 4, No 5, p.492), in which they identified a taste bud sensor for sweetness.

Their work could lead to improved artificial sweeteners that taste more like sugar and have no or reduced bitter aftertaste. This would lessen the need for masking agents and shorten the time required to flavor products. Researchers have identified a gene present in mice and humans as the blueprint for a receptor in taste buds. Although it is not yet proven that this receptor detects sweetness, the researchers say that evidence is strong.

"It is believed that most existing sweeteners are not detected by the olfactory system," says Stephen Liberles, Ph.D., a research fellow in Linda Buck's group. "Ideal new sweeteners would be molecules with high affinity and high specificity for binding to sweet receptors. They would be effective at low doses and not have unwanted tastes, smells, or other side effects."

Almost all artificial sweeteners have been found by serendipity, Liberles points out. "With the discovery of this receptor, we can try a more organized approach to designing artificial sweeteners--instead of through trial and error.

"We are still figuring out much of how molecular recognition works--how the chemicals interact with the tongue and nose. Now that we have the genes in place, we can start figuring out more about how various chemicals interact with the chemosensory organs."