For the first time, high-pressure liquid chromatography makes it possible to separate aroma and flavoring substances from solutions while performing simultaneous sensory evaluations.
Symrise, one of the world’s leading manufacturers of aroma chemicals and flavoring components, has achieved a breakthrough in the art of analyzing the sensory characteristics of food products. A new high-temperature liquid chromatography method known as “LC Taste™” was developed in house and allows researchers to separate aroma chemicals and flavoring components from solutions using a non-toxic blend of solvents. LC, which stands for liquid chromatography, refers to the method used for analyzing mixtures of substances in solution. This marks the first time that mechanical analyses and human taste tests can be performed simultaneously on flavoring and aroma compounds. The key advantage of LC Taste™ over existing methods is that it allows man and machine to analyze aromas and flavors at the same time.
After years of attempts throughout the fragrances and flavorings industry, Symrise has made a critical leap forward, opening up an innovative new chapter in the sensory analysis of food products. Thanks to this method, Symrise and its international customers can now explore completely new opportunities for performing sensory analyses of flavorings.
“This is an important step toward our goal of performing objective sensory analyses on food products,” explains Dr. Gerhard Krammer, Senior Vice President of Flavor Innovation at Symrise.
LC Taste™ is primarily intended for performing two simultaneous analyses of aromas and flavors: one using laboratory instrumentation and the other using the human sense organs. The LC Taste™ user can recognize key flavoring substances such as vanillin, maltol and Furaneol™, as well as substances such as bittering agents, amino acids/peptides, sucrose, flavor enhancers, sugar and capsaicinoids.
Highly interesting industrial applications
Industry will be able to put this new method to interesting use in beverages, yogurts, desserts, ice creams, soups, sauces, spreads, savory snacks, fish, meat, berries, prepackaged meals, sweets, chewing gum, oral hygiene products and medications. LC Taste™ opens up a broad spectrum of new applications. Successful experiments were conducted at Symrise's research laboratories to analyze odor and flavor notes in prepared onion products.
Furthermore, LC Taste™ offers a quick and efficient "taste screening" option that works in conjunction with the Integrated Flavor Concept (IFC) created at Symrise for developing flavorings. The IFC development platform makes it possible to address all key elements in a multisensory experience, including aroma, flavor release, taste, trigeminal perception (pungent, cooling, etc.), texture and visual impression. Newly developed systems to mask bitter components in tea constitute one of the many successful applications of this system.
Immediate human sensory evaluations of samples
The new LC Taste™ procedure that Symrise developed is based on the principle of high-temperature LC with water as an eluant. The mobile phase used here – which poses no risk to human health – may contain other components from the group of physiologically tolerable alcohols, salts, acids, buffers, oils or fats. The sensory evaluation of the flavor and aroma components isolated via liquid chromatography is performed on the cooled eluate.
Immediately tasting isolated components makes it possible to evaluate olfactory (aroma), retronasal (through the mouth to the nose) trigeminal (pungent, warming, cooling, etc.) and taste characteristics.
Many components that act on the senses are still completely unknown
Foods contain substances that act upon the senses, such as volatile aroma components as well as both volatile and non-volatile flavoring substances. These compounds convey key sensory impressions by stimulating the roughly 5 million olfactory cells in the nose and/or the taste buds on our tongues. In addition to olfactory stimulation (smells), these impressions mainly include gustatory perception (tastes), such as sweet, salty, acidic, bitter and umami (from the Japanese word for flavorful). Trigeminal perceptions such as pungent, warming, cooling or tingly round out the overall impression, which is what determines whether a food tastes good to us or fails to meet our expectations. Depending on even the most subtle structural differences in aroma and flavoring compounds, food may taste “home-made” or may fail to give us any real pleasure.
Of the components of food that act on our senses, many are still completely unknown, because they are present in such minute quantities. Nevertheless, because their effect on our sensory receptors is so great, they make a major contribution to the overall aroma or taste. As a result, what is known as the “odor unit value” of one of these substances is far more relevant than simply how much of the substance is present. This value corresponds to the olfactory or gustatory threshold value, which indicates the concentration at which a substance can be perceived by the senses.
Even though earlier methods for analyzing flavors and flavoring substances are highly developed, they are sometimes subject to certain limitations or may be extremely complicated. Chromatography can be used to separate flavoring substances, which can then be evaluated for their sensory characteristics after a certain period of time. Gas chromatography/olfactometry (also called olfactory GC) is used to separate aroma/flavoring substances, which can then be inhaled in the carrier gas and surrounding air and evaluated by smell. It follows that this method only allows for orthonasal evaluation (i.e., directly through the nose), because the mixtures are vaporized and leave the analyzer in the gas phase. High-performance liquid chromatography (HPLC), on the other hand, allows researchers to analyze mixtures of substances in solution, but the components isolated cannot be tasted directly, because the mobile phases typically used are toxic and have to be removed using complex separation procedures. Toxic substances can be removed from flavorings using thermal processes or extractions, but these methods subject the flavoring compounds to extreme stress and can significantly alter them. High-temperature liquid chromatography (HTLC), an offshoot of HPLC, is far more effective. HTLC can be performed using non-toxic solvent mixtures, thereby eliminating the need for complicated purification steps that can affect the flavor constituents. Pure water and/or aqueous mixtures can be used as solvents; additional components, such as oils, fats, ethanol, physiologically tolerable salts such as sodium chloride, and acids such as phosphoric acid can be added to the mixture depending on the application.
LC Taste™, the new high-temperature liquid chromatography method from Symrise, is the most recent example of the Company’s global leadership position in R & D, one of its core competencies. Symrise offers highly innovative, creative solutions and ultra-modern technology, supporting its clients in developing, expanding and maintaining innovative, comprehensive flavoring concepts and successful brands.