Alternative EnhancersAlternative Enhancers

Alternative Enhancers
February 1998 -- Applications

By: Scott L. Hegenbart
Contributing Editor

    While most consumers today seem to be convinced by the evidence that monosodium glutamate is a safe ingredient, every so often someone decides to market a product flagged "no MSG." This means that food product designers must seek alternate ways of achieving MSG's flavor effect. MSG is a very powerful tool; nothing exactly duplicates its flavor-enhancement properties, but opportunities exist to simulate the "MSG effect" by using other ingredients singly or in combination.  MSG is the sodium salt of glutamic acid, an amino acid present in most proteins. Glutamate in its bound form does not produce a flavor-enhancing effect because it is linked with other amino acids to form proteins. To enhance flavor, the glutamate must be in its free form and in its L-configuration, rather than its D-configuration.  Glutamic acid was first identified in 1866 by Karl Ritthausen of Germany. In 1908, the contributions glutamic acid makes to flavor were recognized by Kikunae Ikeda. He also is credited with coining the word "umami," and first suggesting its role as a basic taste. Ikeda further discovered how to isolate MSG from seaweed. MSG became the first affordable material of high purity that could be applied to a wide variety of products. Today, it is commercially produced through fermentation of various substrates, including molasses and corn syrup.Profiling flavor  To try to mimic the effects of MSG, a product designer should understand what it contributes to a food's flavor profile. Although this seems a fairly straightforward concept, the way in which flavor is created is far from simple. Compounding this is the fact that no one is really sure exactly how MSG functions in the complex flavor mechanism.  On a basic level, flavor is a collective sensory experience resulting from the combination of the four basic tastes, aroma and physical factors. In the mouth, molecules of various food components become suspended in saliva during mastication. These molecules roll around the tongue until finding specific, matching receptor sites on the tongue, triggering perceptions of sweet, sour, bitter and salty. At the same time, aroma-producing molecules enter the nose via the nostrils when the food is initially brought to the mouth, and through the roof of the mouth while the food is being chewed. Here, olfactory receptors transmit odor perception to the brain. Last, physical perceptions such as dryness, moistness, astringency and heat, are transmitted through the sense of touch in the mouth.  One area of research indicates MSG amplifies taste perception by working on the receptor portion of the flavor mechanism and has little, if any, effect on aroma.  Explanations as to why this occurs are only theoretical, but two potential mechanisms stand out. One is that receptor sites are being unmasked in some way to make them more available to react with flavor molecules. The other is that there may be an attenuation or amplification of the signal that's being transmitted from the receptor site to the brain. A number of people believe in the possibility of some combination of both mechanisms. But even within receptor theories, little agreement exists.  "There are a couple of camps about that," says Richard Calk, president, Gist-brocades International, King of Prussia, PA. One school of thought is that MSG and/or other flavor enhancers "actually help bind the flavors to the receptor site for a longer period of time. Then there's that other camp that says it actually makes the receptor orifices wider and, therefore, more susceptible to increasing flavor."  Totally contradicting these ideas is the idea that MSG doesn't amplify flavor, but is a flavor in and of itself. This research, particularly that of the last decade, suggests the presence of the fifth taste known as "umami." In the United States, umami often is described as "brothy" or "savory" in foods.  To researchers who don't subscribe to the umami theory, the fact that MSG's effect is dispersed throughout the mouth indicates that it doesn't affect a specific receptor on the tongue such as the way sugar or spices would. Umami researchers, on the other hand, simply believe that the receptors are there-- they just have not been identified yet. To support this, these researchers reference reports indicating the presence of flavor-enhancer taste receptors in certain sea animals.  Complicating this further is that researchers no longer are certain MSG doesn't affect aroma. Studies indicate that people who can't smell still can tell the difference between foods that contain MSG and those that do not. Other research has revealed different chemical compositions present in the package headspace of enhanced and non-enhanced foods. Such testing suggests that an aromatic effect just might exist.  Even if MSG affects flavor and aroma, at least product designers don't have to worry about duplicating physical mouthfeel sensations, right? Wrong. Although MSG originally was thought not to affect this aspect of flavor, research once again indicates otherwise.  One proposed mechanism for this is found in the structure of MSG, which appears to have various structural sites that could bind to any of the basic taste receptors. This broad spectrum stimulation is thought to cause the full-bodied effect in the mouth.  With flavor, aroma and mouthfeel all being potential functions of MSG, mimicking its effects would certainly seem like a much more daunting task.  "Replacing MSG can be very challenging," says Millie Galey, laboratory manager, LifeWise Ingredients Inc., Buffalo Grove, IL. "I've not found anything that works exactly same way as MSG. But, there are ways of duplicating the effect very well."Calling in replacements  Ingredient suppliers offer quite an array of products that can help replicate the MSG effect in foods. In general, flavor potentiators typically are proteinaceous substances composed of either L-amino acids that contain five carbon atoms (like MSG) or of purine ribonucleoside 5¥ -monophosphates with a 6-oxy group (such as the nucleotides). These substances crop up as the active components in various flavor-building ingredients.  About five years after the isolation of MSG, Shintaro Kodama finished a study of dried bonito tuna, another contributor of umami. Later, the active component was found to be the nucleotide 5¥ -inosinate (IMP). In 1960, Akira Kuninaka isolated the other commonly used flavor-enhancing nucleotide-- 5¥ -guanylate (GMP)-- from shiitake mushroom broth.  MSG and the nucleotides often are used in synergistic combinations. Depending on the system, up to eight times the enhancing effect can be observed by using, for example, a 50:50 blend of MSG and IMP. Although this can reduce the amount of MSG, it does not eliminate it.  Nucleotides can be used by themselves, but do not typically give as powerful a flavor result as when used in concert with MSG. Because other enhancing ingredients contain glutamic acid and other chemically similar substances, however, nucleotides often work in synergy with them.  One of the most common sources for the MSG effect can be found in yeast extracts. Two types of yeast extracts are available to product designers. In the first group, yeast is cultivated and subjected to enzymatic self-hydrolysis (or autolysis). This controlled reaction breaks yeast-cell components down into peptides, amino acids (including glutamic acid), nucleotides and salts. This gives yeast extracts significant flavor-enhancing capabilities. Of particular benefit is the synergies between nucleotides and glutamic acid since both are present in the extract. Such synergies can provide the desired enhancing properties with lower use levels, which may help minimize any potential off-flavor contributions from the extract.  Non-autolyzed, or "natural" yeast extracts also are useful in building flavor. Here, the growth process itself is controlled to yield yeasts possessing specific flavor characteristics. This type of extract often is considered a flavoring agent or a seasoning, rather than an enhancer, because it usually lacks the levels of potentiator chemicals found in its hydrolyzed/autolyzed counterparts. Biotechnology, however, is changing this. "We now have yeast extracts that have been genetically altered to bring out the GMP and the IMP," Calk says.  Another common source of an MSG-like flavor effect is hydrolyzed vegetable protein (HVP). Produced by the acid hydrolysis of vegetable matter, such as defatted soy flour, defatted cottonseed, and wheat and corn gluten, HVPs consist of 40% to 45% salt, 9% to 12% glutamic acid, and other flavorings made up of various amino acids and amino-acid derivatives. HVPs had been around long before MSG was isolated and its production commercialized. Hydrolyzed vegetable protein was even one of the substances from which MSG was originally extracted.  This year, Gist-brocades introduced a new enhancer ingredient: fermented soy flour. Taking the technology behind HVPs to another level, the proteins in the soy flour are modified through a proprietary process using enzymes. Like MSG, fermented soy flour boosts flavor. Unlike MSG, however, fermented soy flour doesn't boost meaty notes. Rather, it enhances spices such as ginger, salt and garlic. In particular, this enhancer contributes toward improved dairy or vegetable notes-- flavor profiles in which MSG itself typically doesn't perform that well.Going natural  For the "natural" foods market, using an ingredient that possesses a consumer-intimidating name usually isn't the answer. Fortunately, many ingredients familiar to consumers have substantial amounts of naturally occurring glutamic acid.  One category of such ingredients includes fermented sauces, such as soy and tamari. Here, again, active flavor potentiators are created by the hydrolysis that takes place during fermentation. Other common food ingredients-- such as ripe tomatoes and Parmesan cheese-- contain significant levels of glutamic acid.  Up to this point, one can see a distinct pattern emerge: Many flavor-enhancing ingredients, like MSG itself, rely on the presence of glutamic acid. In fact, vocal anti-MSG advocates claim that yeast extracts, hydrolyzed proteins and other such ingredients are used by food manufacturers to willfully "hide" added MSG in food products. Although this might not represent a realistic perception, FDA recognizes that a small percentage of the population might experience adverse reactions to large doses of MSG or free glutamates. The agency, therefore, has been working on regulations that may require the phrase "contains glutamate" to appear on product labels following ingredients that contain it, such as yeast extracts and certain hydrolyzed proteins. As of this writing, no decision has been made regarding the proposed rule.  In FDA's view, the term "glutamate" refers to all the salts and free forms of glutamic acid. These are commonly formed when proteins are processed into flavor ingredients. As far as savory systems go, flavor enhancers from protein components dominate. If product designers need to remove all glutamate-containing flavor enhancers, far fewer options remain in the flavor toolbox.  Fortunately, LifeWise Ingredients Inc. has developed a line of carbohydrate-based flavor potentiators. These ingredients are proprietary blends of malic acid and various carbohydrates. Each was developed to duplicate the physiological response of MSG in specific food systems.  Another component to consider is that flavor-enhancing standby, salt. Although it cannot duplicate the MSG effect, salt does help to bring out flavors and can be very useful as part of a flavor-enhancement system.Using a system  Because of all that MSG can do, the best way to duplicate it is to use a system of several ingredients. Product designers can build this system using a logical, step-wise approach.  First, determine the concept that is driving the formulation. Is the goal to avoid any potential "contains glutamate" labeling, or is it just to eliminate the chemical-sounding "monosodium glutamate" from the label? Answering this question first will largely determine what ingredients will qualify for the system.  Next, identify any limitations on the system used. First and foremost on this list will be any cost parameters that must be met. This can be a significant hurdle to overcome because MSG is so economical to use.  "There definitely is an economic disadvantage to replacing MSG," Calk says. "MSG is 60 to 65 cents a pound. You may only use a third as much yeast extract, but it is $4 or $5 a pound. You may still potentially double the enhancer cost." However, since flavor enhancers typically have low usage levels, this shouldn't significantly impact a finished product's bottom line.  Finally, the product designer can face the main challenge of rebuilding the flavor profile without MSG. This isn't an exaggeration. MSG contributes greatly to product acceptance, and no true one-to-one replacement exists.  "It really does require blending different things to get the flavor you want and the price parameters," Calk explains. "In a cheese sauce, the replacement system would be very different from what I'd recommend for a vegetable side dish or a beef soup."  To start rebuilding the product flavor profile, first determine what the MSG was contributing to the product. Oftentimes, the MSG is required for general rounding of flavor that helps to balance the system. Produce samples of the product with, and without, MSG, and subject them to the scrutiny of a sensory panel. At the very least, solicit comments from a cross-section of people at your company. The goal will be to determine what flavor notes are now too high or too low with MSG's absence.  After determining which flavors are either too high, too low or missing, the next logical step would be to reformulate the product to boost these individual flavor notes, either through formula ingredients or added flavor ingredients.  In many situations, a product may be described as missing something that isn't clearly identifiable, even by a descriptive panel. This indicates the need for the elusive MSG effect, and an appropriate tool (or tools) from the previous list of flavor-enhancing ingredients must be selected to pull the product's flavor profile together.  While these steps often can solve a balance problem, a product designer sometimes might end up reformulating the product from scratch.  With luck, a complete reformulation won't be necessary, and the designer can start working with the different alternatives to optimize the ones selected and their use level. This process would be very similar to the procedure for any flavor ingredient. Start at the threshold levels of "no effect" and "too strong," then work toward the optimum level through panel evaluations and reformulation based on the 50% rule.  Every MSG-containing food has a specific MSG level falling somewhere between 0.2% to 0.8% on an as-consumed basis. At higher levels, palatability scores don't go up. In fact, at overly high doses, the scores can go down to levels that are lower than control. Panelists typically report an unpleasant mouthfeel. Similar thresholds also exist for many of the other flavor-enhancing ingredients.  Because of the low levels and the potential to overdo, perform some optimization prior to panel testing. A negative panel result might wrongly suggest that a new flavor enhancer isn't working. Particularly when triangulating with extreme levels, designers should perform the initial screening themselves before taking it to a panel.  The last step in formulating with flavor enhancers is to make sure that the reformulation works with the product's system. MSG is fairly resilient to most process conditions. Some of the alternatives, however, may degrade under certain conditions or, at least, suffer from altered performance.  If a product is to be thermally sterilized, test the product under actual process conditions and confirm no significant difference with the control in taste panels. A low pH product may have had the MSG level specially optimized when the product was originally formulated. Many alternative flavor enhancers will be pH-sensitive, and this process may have to be repeated and the use levels adjusted accordingly.  Nucleotides also are susceptible to degradation in humidity levels above 60%. Major losses can result, particularly in foods high in phosphatase activity. The enzymatic activity of wheat also can cause dramatic losses of nucleotides in wet doughs. These losses can occur in as little as 30 minutes at temperatures ranging from 308 to 608C. Dough floor time and manufacturing throughput must be considered if, for example, nucleotides are the active enhancing components in a snack cracker.  In dry mixes, solubility is another important factor to consider. IMP, for example can dissolve completely in five minutes at room temperatures while a 50:50 mixture of IMP and GMP takes 32 minutes. The time between preparation and consumption must be long enough to allow solubilization of flavor potentiators.  Heat and pH also can be modified to improve ingredient solubility. But keep in mind that heat and extreme pH also can be destructive.  Finally, it is important to consider the actual incorporation of the new flavor-enhancement system. Because they are effective at such low levels, it is easy to add improper dosages or to unevenly distribute these ingredients throughout the batch. Premix them with other dry ingredients, if possible. For products with liquid stages, an ideal method is to make a stock solution of the enhancer. For yeast extracts that may only disperse rather than dissolve, make sure the holding tank has gentle agitation for even distribution.  When dealing with delicate flavor issues and the coordination of several taste panels, one option to consider is to ask flavor suppliers for assistance. In this situation, a similar development process will occur, so keeping the supplier's technical staff well-informed is a must.  "The more information the supplier has-- ingredient restrictions, formula and processing details-- the easier it'll be to select the replacement system," says Jane Van Vliet, senior marketing manager, FIS, Solon, OH. "You're completely redesigning the flavor system."  Product designers can take comfort in the fact that MSG's effect can be closely duplicated. It is true, however, that it may take several ingredients, a bit of formulation skill and some development time to achieve the optimum results. Fortunately for product designers, there are enough flavor-ingredient tools and helpful suppliers to get the job done.  Scott Hegenbart is multimedia production specialist with the Department of Food Science and Technology at the University of Nebraska-Lincoln, where he develops computer and web-based methods for teaching food science. During his nearly 14 years in the food and publishing industries, he has authored numerous articles on food product development.Back to top