[Flavors] Vol. 23 No. 3 May/June 2013 ww Umami’s Mysteries Explained By Christ Koetke, Contributing Editor Over the last decade, a series of culinary books have focused exclusively on umami and its role in food. Culinary conferences have followed suit with frequent presentations about this “new” taste and its practical implications. The timing is no coincidence. At the turn of the century, umami was scientifically confirmed as our fifth taste. Terms like savory, meat-like and deliciousness are often used to describe umami, but seem elusive or incomplete. Yet, when you taste it, you know it is there. Umami is not a new concept. Chefs have harnessed its flavor potential for thousands of years in the form of Roman garum, a pungent fish sauce, Asian fermented fish sauces, fermented soy products, sauerkraut, and aged cheeses and meats. The 18th-century gastronome and author of the book La Physiologie du Goût, Brillat-Savarin, described a unique taste in broths and older meatsas "osmazôme." Hard science led to the discovery in 1866 in Germany of glutamic acid, one key to understanding umami. In the early 1900s, Kikunae Ideka, a professor at Tokyo University, also tried to better understand the same taste that Brillat-Savarin sensed. Ideka boiled kombu broth until only flavorful crystals remained; made of molecules composed of glutamic acid and sodium. He named the resulting taste “umami,” which merges the Japanese words for "delicious" and "taste." Fast-forward to 2000, and the University of Miami, where a research team led by Nirupa Chaudhari and Stephen Roper discovered taste receptors in the mouth that specifically register umami sensations, adding it to the four previously identified receptors for sweet, sour, salty and bitter (Nature Neuroscience, 2000; 3(2):113- 119). This monumental discovery forever ended the debate as to whether umami was actually one of the basic tastes. Understanding umami requires a dive into some basic protein science. Proteins are composed of amino acids that are bound tightly together. The order in which different amino acids are arranged and the length of the protein strand determines the characteristics of each protein molecule. Glutamic acid is the most prevalent amino acid in our bodies and is needed for critical transmission in the brain. People consume protein strands containing glutamic acid every day; however, ingesting foods rich in glutamic acid bound up in different proteins does not result in umami taste or perception. To be tasted, it first needs to be separated from protein strands, with the help of protein-splitting enzymes called proteases, or with the assistance of other mechanisms, like long cooking. Once the glutamic acid is unattached, it becomes a free glutamic acid and can elicit the umami flavor. Free glutamic acid also exists as salts in conjunction with positively charged ions, such as a sodium, potassium, calcium or magnesium. These salts dissociate quickly once in solution or upon entering the mouth. Monosodium glutamate (MSG) has several practical attributes, including a more desirable taste profile and a stronger umami response than other glutamate salts. In the kitchen, umami surrounds us in the form of aged cheeses, or aged meats, like Proscuitto and Iberico hams or dry cured sausages. During the aging process, enzymatic activity hydrolyzes (splits apart) the proteins in the meat or dairy product and creates free glutamic acid. As salt is added to www.foodproductdesign.com Page 1 [Flavors] Vol. 23 No. 3 May/June 2013 cheeses or cured meats, there is plenty of sodium available to link with the free glutamic acid. As these or other products age, it liberates more free glutamic acid, which in turn increases the umami profile. This also helps explain other umami-rich ingredients from around the world, including Worcestershire sauce, anchovy paste, kombu, soy sauce, miso, tempe and vegemite. Umami is also part of the story behind a ripe tomato's taste, and why kombu needs to be sufficiently old before it attains its high levels of umami. Umami is also partly behind why the meat of older animals tastes fuller and more intense than the meat of younger animals, as Brillat-Savarin noted. While umami exists in different foods, it also can be achieved in its pure crystalline form: MSG. There is an analogy to be made with table salt (NaCl). In some dishes, we may prefer using NaCl to achieve a salty taste rather than an ingredient like soy sauce, because we prefer not to have the added flavor elements of the soy sauce. But regardless of whether the condiment is sprinkled or poured, it is NaCl. Chemically, the same is true of MSG. It can be attained as part of a food, like Parmesan, or on its own in MSG. Also, just like salt, no matter what the source, it is metabolized the same by the body. When MSG enters the body, it is digested identically, with the sodium molecule splitting off from the free glutamic acid. And speaking of salt, one attribute of MSG is that using it often allows us to reduce a food’s overall sodium content. Creative experimentation (as well as culinary research) suggests that adding a small amount of MSG allows for a 30% to 40% reduction in sodium without compromising taste. Nonetheless, MSG continues to be a source of concern among many food professionals and the larger public. Ever since 1968, with the first claim of "Chinese restaurant syndrome"—flushing, headache, numbness, sweating and other symptoms believed to be cause by MSG consumption— researchers across the globe have analyzed the ingredient for potential problems. To date, the report card is positive after influential organizations like FDA, UN Food and Agriculture Association, and European’s Commission’s Scientific Committee for Food have all declared MSG safe. It is also important to note that MSG is not a food allergen, meaning that it cannot produce a life-threatening allergy. Although FDA states it has received reports that some individuals have various symptoms after eating foods containing MSG, the agency says it has never been able to confirm cause and effect. Over the 50-plus years after Ikeda’s discovery, two additional substances, both ribonucleotides, were discovered to elicit umami-like sensations: 5-inosinate and 5-guanylate. Animal-based 5-inosinates are especially prevalent in bonito flakes, sardines, mackerel, tuna, beef, pork and chicken. Plant- based 5-guanylate is especially powerful in dried shiitake mushrooms and, to a lesser degree, in other mushrooms. The reason these two ribonucleotides are so interesting to the culinary community is because they have a synergistic effect with foods rich in glutamates. Thus, combining one of the ribonucleotides with a food rich in glutamate is not 1+1=2, but rather 1+1=4, or even 8. According to Ikeda, the reason dashi, the foundational Japanese stock, works is because it combines kombu (glutamate) with bonito flakes (5-inosinate). The net effect is that it carries an unexpectedly strong flavor profile. Similar taste experiences explain the success of cheeseburgers (cheese—glutamate, beef—5-inosinate), Bolognese sauce with Parmesan (tomato and Parmesan—glutamate, beef—5- inosinate), and Caesar salad dressing (Parmesan—glutamate, anchovy—5-inosinate). www.foodproductdesign.com Page 2 [Flavors] Vol. 23 No. 3 May/June 2013 As many chefs and food product developers are aware, stimulating all the senses, even slightly, excites the palate to a greater degree and makes for a more full, satisfying flavor experience. For instance, adding a small amount of salt to a chocolate dessert adds another taste beyond chocolate’s intrinsic tastes of sweet, bitter and sour. In essence, it raises the overall flavor profile and makes the flavors taste richer. In a similar way, harnessing the power of umami helps to complete the taste experience by having the maximum number of taste receptors interpreting a particular food. For instance, the trend of adding bacon to chocolate dishes makes sense because all five tastes are being excited. The bacon contributes salt and generous amounts of umami. Just as we think about salt or sugar levels in recipe or formulation development, consciously thinking about umami levels in food formulations will yield a more complete and interesting flavor experience. For instance, choosing a cheese that has been aged for a longer period of time will deliver a stronger umami punch than a younger cheese. Reaching for fermented soy or fish sauces will add complex flavor profiles, salt and significant umami. Seasoning foods with small amounts of MSG, especially foods rich in 5-inosinate or 5-guanylate, will take advantage of their special synergistic relationship with glutamate. Armed with an acute understanding of umami and the ingredients that deliver this fifth taste, chefs and product developers can improve overall flavor profiles of many applications, both savory and sweet. The key is to consider it just like we analyze our creations for the other four tastes. Christopher Koetke, CEC CCE HAAC, is vice president of the School of Culinary Arts of Kendall College. Reach him at [email protected]. www.foodproductdesign.com Page 3 .