Mitigating Off Flavors

By Cindy Hazen, Contributing Editor

Few food developers can create a product thats spot-on. Most of us can make educated guesses, but we work by trial and error. Sometimes, the formula requires a full-blown correction. When were lucky, a simple change moves the product closer to alignment.

Understanding how flavors workand how they can go astraycan help us avoid complete write-offs and will lead us closer to the fine-tuning aspects of product development.

Sources of discord

Some ingredients are inherently difficult. They dont play well with others. They come across as too loud. They may even be bitter. Ironically, the most obnoxious may offer the most benefit to the formula, so we need tools to subdue their impact.

Paulette Kerner, director of marketing communications & research, Virginia Dare, Brooklyn, NY, suggests specific applications that would benefit from masking are products that contain fortification, alternative sweeteners, soy, whey, a high amount of fiber, vitamins and herbs. Omega-3s can contribute bitterness."

Vitamins and minerals are notorious offenders. For especially bad boys, microencapsulation is the best solution, according to Ram Chaudhari, Ph.D., senior executive vice president and chief scientific officer, Fortitech, Schenectady, NY.

Thiamine, also known as vitamin B1, is the most objectionable. It has sulfur in the chemical formula, and that is very unstable," Chaudhari saysnot to mention unpleasant.

In the mineral category, iron and copper take the lead in lending a metallic aftertaste. Potassium runs a close second and leaves a lingering, metallic and bitter flavor.

Calcium, on the other hand, can contribute varying degrees of chalkiness and grittiness. Chalkiness depends on the source," says Chaudhari. In calcium carbonate, chalkiness is very pronounced. If you have dicalcium phosphate, its not as pronounced, but it is always there."

Aside from an inherently bad-tasting ingredient, its important to remember that, in product development, all processing conditions must be considered. Packaging and storage conditions must also be factored in. At every step, complex interactions can occur that can result in off notes.

This is also true when selecting masking flavors, because they are not immune to interactions. Flavors designed to distract from off notes are subject to all processing conditions, and these must be considered in the masking development," cautions Mary Svboda, senior flavor chemist, Synergy Flavors, Wauconda, IL.

Matters of perception

In the quest for flavor balance, its best to begin with some basic sensory science. Researchers agree that taste perception is based on receptor sites on the taste buds in our tongues, and they can detect only one type of taste sensation," says Mariano Gascon, vice president, R&D, Wixon Inc., St. Francis, WI. Yet there are hundreds of receptor sites on each taste bud. In general terms, the way that we perceive taste is by stimulation of these receptors. But, if you can stimulate them, you can also inhibit them." He notes that some of the mechanisms for modulating taste are known, but the vast majority are poorly understood.

Gascon classifies taste modifiers, or taste modulators, into three categories: enhancers, maskers and modifiers. Enhancers are those that will elicit a response," he says. For example, a chef would add salt to foods to intensify the flavor. In the flavor world, a flavor chemist will add ethyl maltol to enhance the fruity and sweet notes in a flavor."

Maskers will inhibit the response. Consumers add sugar to a cup of coffee to reduce the bitterness," Gascon notes. In the flavor world, the flavor chemist would add vanillin to enhance the sweet notes in a flavor, thus helping to cover the bitterness."

Modifiers are substances that will inhibit some receptors, but produce the opposite effect on a different type of receptors. A good example of this is miraculin, a protein isolated from miracle fruit (Synsepalum dulcificum) that can modify the perception of sourness to turn it into intense sweetness," Gascon says.

Svboda notes that flavor masking can be partially described as flavor distraction, or creating a diversion from the element that requires masking. Genuine masking implies that you are covering up bitterness or other off notes. However, reducing the intensity of the bitterness by using one of the other taste sensationssweetness, sour or umamito lessen the impact is very effective. Since every product is unique and there is no magic bullet, each product may require a unique solution specifically engineered to address the characteristics that need to be masked." She notes that, according to the Monell Chemical Sciences Center, Philadelphia, PA, and others, one of the few real bitter blockers is salt, because it actually blocks the bitter receptor channel."

Gascon points out that some of the characteristics that need flavor assistance are not really a taste, but a sensation. Astringency is a dry, puckering mouthfeel. If something is described as metallic, its more of a perception. They are feelings caused by substances that actually denature the salivary proteins, causing a rough, sandpapery sensation in the mouth. Unpleasant notes, described as excessive salt, sour, bitter, astringent or metallic, require delicate adjustments from one application to the next."

Complex flavor problems can require a combination of masking agents. When one taste perception is modified, another can step out of balance and need reigning in.

Reducing sodium

Maintaining flavor while reducing salt is a timely challenge. Products used in development that will enhance natural flavor while reducing sodium seem to offer the most benefit," says Svboda. For example, lactic-yeast extracts can be used in cheese sauce, cheese powders, dressings, etc., to enhance the natural dairy flavor while reducing the overall sodium content."

Tom Jones, applied technology manager, Kalsec, Kalamazoo, MI, works with meat products and finds sodium-restricted products present two challengesmasking bitterness from the potassium ion in KCl salts while enhancing the salty perception from the sodium ion in NaCl. With both challenges, the basic idea is to either heighten the umami sensation in the mouth or reduce the potassium component in the salt blend. Either or both in combination masks undesirable flavors and/or enhances the salty perception."

Certain combinations of spices and herbs can be used to potentiate the salty perception while muting the bitterness associated with potassium chloride, and highlighting desirable flavor characteristics. Because salt helps control water activity, and it is important to inhibiting microbial growth during storage and distribution, Jones recommends shelf-life studies and formal sensory testing.

An encapsulating solution

Sometimes, when an ingredient or flavor does not mix well with others, the best approach is to segregate it. According to Tom Tongue, director, product development, IFP, Inc., Faribault, MN, encapsulation is an effective way to deal with unacceptable flavor issues or enhance flavor. Encapsulation isolates an ingredient until the desired release or interaction," he says. The companys modified form of conventional fluid-bed encapsulation applies layers of microscopic droplets of coating onto the surface, creating a multilayer coating shell. This shell is designed to create a custom barrier around the active ingredient.

Flavor components can react to oxygen, moisture or other ingredients. These interactions can be minimized through encapsulation technology. Shelf life is enhanced by minimizing the creation of undesirable flavors like rancidity.

Tongue cautions that encapsulation is not a single technology, so the choice of coating technology is critical. The process of encapsulation creates a barrier, but these barriers can have significantly varied survival and release profiles, and will have equally varied impact on ingredient cost," he says.

Particle size is another consideration, because it can impact visual appearance and mouthfeel. For instance, it may not be desirable to see large off-color particles within an otherwise white powder," says Tongue. Large particles can also be incompatible with fine powders and can stratify and/or create an undesirable gritty texture. On the plus side, larger particles can provide a greater impact, for example the sour blast sensations from granular citric acid, or a desirable consumer recognition such as pretzel salt."

Its also important to consider the choice of coating material. Zero-trans, partially or hydrogenated oils, or GMO materials, for example, will impact labeling and regulatory issues.

Survival and release properties are more-complicated considerations. Formulators can use attributes such as melt profiles or brittleness to their advantage. Coating modifiers such as emulsifiers, alternate oils or water solubles can expand the survival and release profiles of coating options," says Tongue.

Spicy distractions

In the meat and poultry industry, spicy or subtle flavor profiles can mitigate unwanted off flavors and improve palatability in grass-fed beef products and value-added meat products.

Suppressing some flavors, as in value-added products from grass-fed beef, is a challenge that requires a balancing of the spice components in a seasoning that mutes or masks an undesirable flavor without necessarily imparting a typical seasoning flavor," says Jones.

Rancid flavors created as a result of oxidation present a challenging issue. In addition to the off notes associated with oxidation, oftentimes the desired characterizing flavors can be muted. The use of rosemary, standardized for antioxidant activity, allows the seasoning to be more fully expressed by inhibiting the development of rancidity and allowing the characterizing notes to come through for the consumer. So, rather than using seasonings to mask rancid flavors, natural antioxidants offer a clean-label solution to the undesirable results from oxidation," says Jones.

A vinegary flavor problem can emerge when diacetates are used in the formula. Many product developers only use diacetates in those formulations where twangy notes are typical, or at least compatible," says Jones. But even these products deserve flavor balance. For example, when reformulating a barbecue seasoning, the overall flavor intensity can be enhanced by optimizing seasoning combinations and interactions. On the other hand, it may be more complicated to try and mask the vinegary notes of diacetates in a hot dog where twang is not a part of the inherent flavor profile."

Simply using more seasoning is typically not the answer to masking undesirable flavors. The spice components or building blocks of a seasoning are balanced based on the desired flavor profile and usage level," Jones continues. Just increasing the usage level may make the more-subtle savory background notes too dominant. The oleoresins clove and celery are sometimes used in seasoning blends as sweet background notes, but increasing the usage level of the seasoning blend could increase the cloviness (eugenol) or celerys bitterness (thalides). Its more important to work with your flavor supplier to guide your masking process in order to make sure the seasoning profile maintains the desired balance."

Flavorful details

In most applications, it is not best to use more flavor when trying to mask some ingredients," says Kerner. Over-flavoring, excessive use of flavor, can create off notes itself, and can unnecessarily add to the cost of the finished product."

Kerner recommends beginning with the base nearest to neutral before adding flavors. Choosing a flavor with certain top notes that work with the base rather than against the base is a secret to remember," she says. For example, sometimes a jammy strawberry flavor may work better than a green strawberry flavor in a specific prototype with certain fortifiers."

Its important to involve suppliers early in the development cycle. Its best to start in the early stage to mask the off notes in the base rather then try to mask off notes in a nearly finished product," advises Kerner.

Gascon stresses a holistic approach. Look at the complete formula. Sweeteners, acids, starches or fats can sometimes play a role in suppressing off flavors.

To understand the multifaceted role of flavor in a product, Svboda offers the example of a filled doughnut with a starch-based strawberry filling. When a client requests a strawberry flavor be added to the filling, the product not only has an increase in strawberry flavor, but the starchy flavor of the stabilizer or bulking agent is decreased," she says. Good flavor design will accomplish both goals, even though one of them may be unintentional. A strawberry designed to mask starchy notes in a filling may not be the same strawberry designed to mask vitamins and minerals in a beverage."

Consider next a baker who does not use vanilla in a chocolate-chip cookie. The flavor of the wheat will make the cookie less palatable," says Svboda. Adding vanilla masks the wheat-type off notes."

Svboda suggests thinking about all individual flavor characteristics to be masked in the product. Understand that one size will not fit all when it comes to devising a masking solution," she says. Try multiple levels until a suitable level is reached."

Yet Svboda offers a ray of hope for those who tire of relentless trial and error. Many, but not all, reactions of flavor compounds in processed foods can be predicted," she says.

Cindy Hazen, a 20-year veteran of the food industry, is a freelance writer based in Memphis, TN. She can be reached at [email protected].