In December, 2001, Xiagen Yang and a dozen other scientists trekked into the Masaola rain forest in the northeast corner of Madagascar. Pushing aside the lush, overgrown foliage, Yang followed his nose, sniffing for exotic aromas. These explorers weren't on an ordinary scientific mission: They were flavor hunting.
Yang is an analytical chemist and the manager of natural-products research at Givaudan, a Swiss chemical company. Whenever he detected an unusual bouquet, he set out a "microtrap," which collects the air where the aroma is found. Back in a makeshift lab at his camp, Yang forced his prize catch through a gas chromatograph, which separates the gas into its individual components, then through a mass spectrometer, which identifies known molecules.
OLFACTORY TREASURES. By the end of the mission, Yang had taken 150 samples, including the scent of the previously unknown rara flower, whose aroma is combination of natural strawberry, floral, jasmine, and honeysuckle. Eighteen month later, those samples have made their way into as many as 20 Givaudan flavors, which are used in dairy products, hard candies, and beverages. Givaudan's next rain forest expedition is set for 2004.
Developing sophisticated flavors for packaged foods these days requires nothing less than that kind of effort. Hypercompetitive flavor companies -- most of them based along an industrial stretch of the New Jersey Turnpike -- sell about $7.5 billion worth of flavorings annually, according to research firm Fredonia Group. So specific are today's flavors that these outfits can differentiate between a "natural" strawberry flavor found in, say, a Pop-Tart, and the "jammy" strawberry taste used in hard candies. Now, a food processor that wants a strawberry flavor for a new dairy product, for example, can get its order within 48 hours.
To keep growing, flavor businesses have gone one step further: They're creating "layered" flavors. Not just raspberry, but cool raspberry. Not just cheddar-cheese chips, but spicy salsa cheddar chips that leave a tingle on the tongue.
CLEANER PROFILES. All of which is much easier said than done. Layered flavors require each molecule included in the formula to be more pure, more precise than ever before. No longer can flavorists simply use menthol, a traditional cooling agent, to make cool raspberry candy, because menthol's mint aroma overpowers raspberry.
So an army of flavor hunters such as Yang are working to discover and develop new materials that have cleaner profiles. "The wave of the future is the ability to create more specific molecules that only stimulate a specific subset of receptors," says Marcia Pelchat, a sensory psychologist at the Monell Chemical Senses Center in Philadelphia.
To understand why such purity is essential, consider the basics of taste and flavor. Taste comes from five qualities you sense with your tongue -- salty, sour, bitter, sweet, and umami, a meaty or savory sensation. Flavor is made up of sensations from other sensory systems, especially smell.
"SENSORY IRRITANTS." Without smelling a food's aroma, Pelchat says, it would be impossible to tell a peach from a grape (both are primarily sweet) or beef from lamb (both are primarily umami). To demonstrate the importance of smell in flavor, Pelchat often gives lay tasters three jellybeans, flavored with banana, licorice, and coffee. She then asks them to close their nasal passage with nose clips -- after which all three jellybeans taste the same.
The method for creating pure tastes and aromas has become well understood over the years. But making "sensory irritants," which tell the body whether it's experiencing heating or cooling, is more difficult. Coolants should create the illusion of a temperature drop to about 13 to 15 degrees Celsius (55 to 59 degrees Fahrenheit). To do that, flavorists search out molecules with no distinctive aroma that can trigger a neurotransmitter to stimulate nerve endings and send a message to the brain that the temperature has changed.
The industry's greatest leap in the past 20 years has come thanks to Japanese chemist Ryoji Noyori, who developed a method of artificially -- and efficiently -- making chemical compounds that previously only nature could create. In many chemical compounds, molecules appear in two contrasting forms: The components are identical, but the structures are mirror images, like a left and right hand. The reactions caused by each molecule can be vastly different. In menthol, one part called L-menthol creates a cooling effect, while the other, called D-menthol, has a strong aroma of mint and is quite bitter.
NOBEL WINNERS. These molecular differences can even be dangerous: In the 1950s, doctors widely prescribed thalidomide to pregnant women to help them sleep. One molecule did just that. Its other half was toxic and caused serious birth defects in newborns.
Until Noyori made his discoveries, only sophisticated biological systems in living organisms could select the "useful" molecule. Noyori developed a catalyst to allow scientists to produce the desirable molecule with 100% certainty. And in 2001, he and two American researchers won a Nobel prize for their work. Japanese flavor and fragrance company Takasago, for whom Noyori is an outside director, uses his method to produce nearly half the world's synthetic menthol. The technique, designed for the flavor industry, has also been used to develop synthetic vitamin E, vitamin K, and anticancer drug prostaglandin.
For competitive reasons, flavorists won't reveal which compounds end up in which food products. But a quick look at grocery shelves demonstrates the extent to which packaged-food makers have embraced the possibilities: You'll find spicy salsa and barbeque chips that create a pop of heat when they first touch your tongue, and spicy pasta sauces and salsas that create a more lingering heat.
SIMULATING PROOF. Takasago uses heating ingredients to mimic the burning sensation of alcohol, says Charles Manley, the company's vice-president for flavor science and technology. When added to diluted 60-proof vodka, heating flavor provides the same strong burning sensation of standard 80-proof liquor. The same flavor can be added to mass-produced fruit pies to create the sensation that the pie has been heated -- even if it's at room temperature.
Similarly, coolants are in everything from salad dressings to "tequila and lime" tortilla chips. And Takasago and others use jambu oleoresin, a leafy plant grown in Southeast Asia, to provide a tingling sensation in high-end ice teas and sport drinks.
Cool products don't always avoid a minty effect. Menthol flavors are just the trick for covering over the foul taste of chemicals used in popular whitening toothpastes, plaque-killing chewing gums, and breath fresheners, says Tom DeBiase, International Fragrance & Flavor's director of global technology business development. Witness the soaring sales of power mints and breath fresheners that melt on the tongue and create a cold, fresh sensation. According to Packaged Facts, a division of Market Research.com, the availability of new, intense tastes has increased the market for mints and gum over the past several years, to more than $3.6 billion. By 2007, the market will reach $4.3 billion, predicts Don Montouris, acquisitions editor for Packaged Facts.
Characteristically, flavorists are staying mum about the next killer food trend. "Flavors will be bigger and will stimulate more and more of the nervous system through texture, temperature, and irritants, not just taste and aroma," Takasago's Manley says coyly. But all agree on one thing: Whatever the next wave in flavors may be, high-tech lab tools and exotic exploration will put them on the table. By Jane Black in New York