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Stir Bar Sorptive Extraction (SBSE) helps determine odor causing substances The Twister sniffs out the aftertaste

What do wine and mouthwash have in common? Both leave an aftertaste. How aftertaste develops has not yet been clearly determined, but it is well known that flavors and odors play an essential part; in fact, a more correct term would be “afterodor”. A scientist from the German Research Laboratoy for Food Chemistry sheds some light on the secrets of how we taste.

sing a method based on Stir Bar anatomy. Minor tricks of the trade and full experience of tasting food and drink. Sorptive Extraction (SBSE), the some experience can then help even Whether food or drink has a short or long U German Research Laboratory amateurs to a more qualified assessment lasting taste, and whether it turns out to for Food Chemistry has succeeded and maybe to more enjoyment. To sum it be enjoyable, depends mainly on to what for the first time in determining minute up: wine tasting is not just for specialists. extent and for how long characteristic amounts of odor-causing substances in Even the ancient Romans knew that a flavors find their way from the oral cavity the mouth at defined time intervals after wine should be judged not only by its via the throat to the olfactory sensors in the consumption of food. The method can taste, but by its color and aroma as the nose. This process is referred to as be used to determine aftertaste and it has well. Sounds simple, and it actually is retronasal odor perception. In contrast, helped explain how aftertaste develops. – at least the part about the taste. The when flavors are sensed in combination There are different ways to approach flavor evaluation, the palate test, still with inhalation through the nose, it is a good wine. Connoisseurs always swear holds many secrets. Simple descriptors called orthonasal odor perception. by their own personal method. Certain such as sweet sour, salty bitter, creamy, But how do the flavor compounds principles and details, however, simply spicy or toasty cannot fully describe the that are released from foods or beverages follow from instinct and from human complex interactions that provide the in our mouth reach their destination,

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for a short time and small amounts of her physiological miracle of sensory Stir Bar Sorptive Extraction (SBSE) helps aroma components reach the olfactory perception is outwitted: determine odor causing substances bulb via the throat. By skillfully opening and closing “The real perception of the wine the mouth and the palate barrier, and or coffee aroma does not occur until by combining these motions with a immediately after swallowing, with the special breathing technique, flavors are first breath.” pumped from the oral cavity through An aroma impulse, by the way, can the throat cavity and on into the nose. also be registered when we place food This process is often accompanied into our mouth. Andrea Büttner: „This by sounds that may seem less than is an important protective mechanism appetizing to the uninitiated. The provided by Mother Nature. Through it process can be examined and traced we receive a first impression on whether via PTR-MS. Incidentally, experienced Open palate while food is inserted into the mouth the substance in our mouth is fit to eat or wine tasters never bite off more than with a spoon (video-fluoroscopic snap-shot) not.” The phenomenon has physiological reasons: as soon as we open the jaw, the tongue-palate barrier opens up for GC-System with the olfactory sensors? To adequately a short time. After closing mouth and MPS 2 and TDU answer this question it is not enough to jaw again, excess air is released from for fully automated watch a connoisseur during wine tasting. the mouth cavity into the nose via the analysis of up to 196 You can reach some conclusions about throat cavity; flavor substances from the GERSTEL Twisters the person from the smacking, slurping food are thus transferred to the olfactory and guttural sounds emanating during sensors in the nose, where a discernable the process of expert tasting. Still it sensory impulse is released through the remains unclear exactly how the odorous sensory bulb to our brains. Proof that this substances reach the olfactory sensing is how the process works was provided apparatus. If modern imaging tools are by real-time breath analysis using Proton used, however, it becomes obvious that Transfer Reaction Mass Spectrometry this is a precisely controlled process, (PTR-MS). which permits a flavor transfer only at After taking a sip of wine, a test certain times. person exhales through the nose and then closes the lips and tongue- Learning from Mother Nature: palate barrier. In the on-line PTR-MS The way of human tasting measurement, a distinct initial peak is If there is food in the oral cavity and seen. The signal is due to the presence lips and jaws are closed, the palate and of ethyl acetate formed by reaction tongue base form a barrier that actually between ethanol and acetic acid. This seals the oral cavity and prevents us highly volatile compound is easily sensed from unintentionally swallowing food at relatively low concentrations and often or literally getting it down the wrong identified as a nail polish smell. In wine, pipe. A small experiment demonstrates ethyl acetate occurs naturally. In this the incredible efficiency of this natural experiment, ethyl acetate is used as a lock inside the mouth. Take a small sip marker to detect the transfer of volatile they can chew, that is, they never take of coffee or wine and leave it in your wine flavor compounds from the oral too much wine into their mouth when mouth. Now close your lips. In doing cavity to the nose cavity. The initial ethyl tasting. Apart from the risk of choking, so, keep your lower jaw completely still. acetate peak during wine intake lasts this would lead to a reduction of the What is your perception? Now start to only 2.5 seconds. Even though the test vapor phase volume in the mouth, chew. Does anything change in your person keeps the wine in the mouth for effectively reducing both the transfer of perception? And then swallow. What is some time, only isoprene, a metabolite flavor compounds into the vapor phase your perception now? which is released into the atmosphere and the subsequent transfer of the vapor „As a general rule, taste impressions via our breath, is detected, but no ethyl phase to the nose cavity. If, on the other like sour, bitter, sweet or salty can be acetate. hand, the amount of wine taken into the detected during the first part of this oral cavity is too small, dilution of the experiment, but no typical flavor notes You can’t smell with your sample by saliva and a too large volume like toasty, fruity or flowery“, explains mouth full of vapor phase can significantly impact Dr. Andrea Büttner, a scientist at the Though the experienced connoisseur the sensory perception. The volume German Research Laboratory for Food seldom swallows during wine tasting, he needs to be just right. Chemistry. During chewing, namely or she is able to give a comprehensive Back to the experiments: As soon as the second part of the experiment, the retronasal evaluation of a wine. Using a the test person has swallowed the wine natural barrier in the oral cavity opens few tricks of the trade, mother nature and and taken a breath, there is another

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To avoid contact, and thus a direct extraction of substances from the oral mucosa, a special sampling vessel for the Twister has been developed. BOSS provides unobstructed access of saliva and gas phase to the Twister, thereby ensuring an efficient extraction of flavor compounds. 0 1 2 3 4 5 6

clear ethyl acetate signal. Even after the on Stir Bar Sorptive Extraction (SBSE) the oral cavity. The lips are kept sealed wine has been swallowed, volatile flavor using the GERSTEL Twister. The Twister and breathing only takes place via the compounds from the wine are detected in is a glass-coated magnetic stir bar with nose. After a specified period of time, the breath. Even though there is no more an outer coating of polydimethylsiloxane the glass capsule is removed from the wine in the mouth, volatile compounds, (PDMS) that can extract organic mouth and the twister taken out and that are typical of the aroma for the compounds such as flavors or off-odors dabbed dry on a lint-free paper. The tasted wine, are released and can be from aqueous and other liquid samples. extracted compounds in the PDMS determined through sensory perception Direct contact between the Twister and are determined by thermal desorption or by using analytical instrumentation the oral mucous membranes could lead in combination with GC separation such as gas chromatography (GC) with to extraction of adsorbed compounds and olfactory detection. In her work, olfactory detection or MS detection. The that do not contribute to the sensory Dr. Andrea Büttner established a clear duration of the “aftertaste” depends on perception. The Twister is kept isolated correlation between the concentrations several factors, among them the extent to from the membrane surfaces by placing of extracted flavor compounds and the which flavor compounds are metabolized it inside a small, perforated glass vial. flavor perception of the subject. With by the saliva, resulting in reduced The vial is sealed with a glass stopper BOSS it was possible for the first time sensory perception and a displacement and placed inside the oral cavity of to detect even small amounts of flavor of the aroma profile. Thioles, such as the test-person for a defined period of compounds in the oral cavity at any 2-furfurylthiol, that adds a typical roasted time. The perforated vial walls ensure given point in time after consumption of coffee flavor, or 4-mercapto-4-methyl-2- unobstructed contact of the Twister with a beverage or food sample. pentanone, characteristic for Sauvignon- saliva and with the oral cavity gas phase. In other words, for quite a while after Blanc wines, are efficiently metabolized The test person moves saliva around the a food has been swallowed, traces of by saliva. Earthy pea or bell pepper type vial during the extraction phase. flavor compounds can be detected that notes, however, are saliva persistent. Sampling using the BOSS procedure have been absorbed by oral mucous. Flavor persistence was determined is performed as follows: a subject tastes These can produce a flavor impression based on sensory evaluation in parallel a food sample and subsequently places over a period of time, known as the with direct saliva analysis using the the perforated glass vial with the aftertaste. This finding is especially Buccal Odor Screening System (BOSS). Twister into his or her mouth. The vial of interest to food manufacturers. BOSS is a novel analysis method based is moved around in the saliva inside Customer acceptance and the success of any given product in the marketplace depends heavily on whether consumers enjoy the taste and aftertaste. In addition, Dr. Büttner considers the BOSS �������� method a promising, extremely helpful ������������� instrument for diagnosing halitosis, as well as for examining the effectiveness of toothpastes and mouthwashes.

��������� Real-time PTR-MS It can be safely said that the BOSS ���������������������������� ������������������������� �������������������������� ���������� monitoring of volatile system can neither replace wine tasting ��������� compounds that nor can it provide specific conclusions

��������� pass the olfactory about individual properties of wines center and are and other products. It is simply a tool to ��������� exhaled through the describe the aftertaste of a given product.

��������� nose when drinking Dr. Büttner adds: „Wine tasting is and will ��������������� wine. remain a subjective matter, incidentally, ��������� one that is more strongly influenced by

��������� the mood and the environment in which it �� �� �� �� �� ��� ��� ��� is performed than most people realize.“ ����������

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