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A chemist with a sophisticated sense of smell studies the aroma of the celebrated orange blossom.
By JEFF KLINKENBERG, Times Staff Writer
© St. Petersburg Times, published April 9, 2002
LAKE ALFRED -- In the old days, when fewer cars had air conditioning, the world was still a cool place, especially when the perfume of spring wafted through the Florida night.
"We'd pull off the road with the windows open," Russ Rouseff says. "My wife and I would sit in the moonlight and smell the orange blossoms."
They'd park on U.S. 27 in the middle of the state and take sharp, deep breaths. The fragrance of the citrus flowers detonated in their nostrils, bombarded olfactory membranes up high and was transformed magically from gas into liquid. Tiny hairs -- cilia -- swept the citrus mucus to the brain's olfactory nerves less than a quarter-inch away. The Rouseffs' brains naturally broke into mighty grins.
"Ah! Orange blossoms," announced the brain core. "Isn't spring in Florida heavenly?"
Russ Rouseff is as romantic as the next guy when it comes to singing the praises of the state flower. But he is also a University of Florida chemist whose specialty includes not only the flavor chemistry of citrus, but how humans perceive those flavors.
A man with an educated nose takes something as innocent as citrus blossoms more seriously than the rest of us.
Indeed, scientists who work for the fragrance industries, including perfumemakers, come to visit. Rouseff unleashes them in the groves. They saunter among the trees taking hearty gulps of air, hoping their olfactory nerves will not let them down. But sometimes they do
"Fragrance is a very complicated thing," says Rouseff, one of those guys who bites into a slice of grouper and begins describing in chemical terms exactly what he thinks he is tasting.
Identifying specific citrus aromas -- "volatiles," Rouseff calls them -- can be especially challenging. Humans capture hundreds of different fragrances in a gulp of air. Some fragrances are stronger than others, but even weak ones might be important.
Fragrance industry scientists don't completely trust their own sense of smell. They carry machinery to collect citrus blossom aromas for later analysis. They are pretty sure a blossom on the tree has a smell superior to that of a blossom picked moments later. Their task is finding out the right combination of chemicals and putting the essence into their perfumes.
Old-timey Floridians, of course, spent little time analyzing the perfume of spring. They simply enjoyed it.
It was easier then. Almost any town, even crowded cities such as St. Petersburg, boasted any number of groves. A resident who stepped out the front door to pick up the morning paper was overwhelmed by the fragrance. At dusk, homeowners sat on their front porches -- porches are an endangered species in 21st century Florida -- and breathed in the glory of the grove.
Blossoms were celebrated far and wide.
Wrote the poet Walt Whitman:
To my plain Northern hut, in outside clouds and snow,
Brought safely for a thousand miles o'er land and tide,
Some three days since on their own soil live-sprouting,
Now here their sweetness through my room unfolding,
A bunch of orange buds by mail from Florida
In 1927, a railroad line launched the Orange Blossom Special to the accompaniment of bathing beauties and orange perfume. The luxury train brought well-heeled tourists from the Northeast to Miami and St. Petersburg. A decade later a homesick Florida boy, Ervin Rouse, tuned up his fiddle and wrote Orange Blossom Special, which has since been recorded by hundreds of artists from Johnny Cash to Bill Monroe and his Bluegrass Boys.
When Rouseff got his doctorate from the University of Georgia and joined the Florida research lab in 1972, he thought he was working in a flowered paradise. The lab, built in 1917 near Winter Haven, was in the middle of Florida's citrus belt. Just down the road was a folksy attraction known as the Citrus Tower. From the top, tourists supposedly could see 17-million citrus trees at once.
"Now almost all the groves around here are gone," Rouseff says. "You can go up the tower, but mostly you see golf courses and housing developments. I miss the old days."
A devastating series of freezes, scattered about two decades, finally subsided in the 1990s. By then, many of the frozen groves were under pavement or St. Augustine grass. Hard-core growers, the ones who refused to quit, migrated south toward Lake Okeechobee and began planting.
North Florida, where citrus once was king, has all but lost those perfumed spring nights. Central Florida might be in the process of losing them. But not quite yet.
At least Rouseff still has 225 acres of groves behind the research center. And he has a pretty good sense of smell with which to enjoy the blossoms.
To him, studying citrus blossoms and their fragrance is more of a hobby than real work. He spends most of his time trying to make orange-juice concentrate taste more like the genuine nectar of the gods. When concentrate was invented during World War II it tasted horrible. Over decades it slowly improved, but only an industry lackey would insist that concentrate tastes like fresh-squeezed.
Rouseff and research assistants are unwilling to give up the fight. They spend hours sniffing citrus fragrances in hopes of finding the perfect chemistry for a better juice. Rouseff has a machine, a gas chromatograph-olfactometer, which can actually measure odors. As it does its work, a researcher does the same with his nose. The researcher breathes from a pipe connected to the machine and writes down a description of the scents.
"Humans can detect things machines can't," Rouseff says. "What the machine measures as significant may not be what the human nose believes is pleasant. There's no replacing the human nose."
A human nose knows what it knows. Or at least it thinks it does. One of Rouseff's researchers grew up in Alabama as a God-fearing Baptist. He recently smelled a musty citrus odor through the machine and described it as "old church." Another researcher, the staff romantic, described a delicate aroma as "perfume on a woman's neck."
Nobody who has spent any time near an orange grove in full flower would argue with romance. Most perfumes, in fact, are derived in part by citrus oil. They do everything but shout, "Come hither."
Once citrus blossoms were an important accessory in every society bride's wardrobe. She absolutely had to have an orange-blossom garland in her hair when she marched down the aisle. Citrus blossoms were even considered a honeymoon helper -- at least in the fourteenth century. The spicy parts of Boccaccio's Decameron had readers panting at the juicy passages involving orange-scented lovers and courtesans who seduced the rich and powerful after sprinkling sheets with orange perfume.
The amorous-minded Mr. Boccaccio might turn in his grave if he had to wade through Rouseff and company's recent scientific literature, including 2-Methyl-3-furanthiol and Methional are Possible Off-Flavors in Stored Orange Juice: Aroma-Similarity and Using an Ion-Trap MS Sensor to Differentiate and Identify Individual Components in Grapefruit Juice Headspace Volatiles.
On the other hand, he'd be glad somebody thinks the subject is important enough for study. And he'd appreciate that Rouseff and his wife liked to park in the moonlight and smell the blossoms.
Rouseff is very much interested, after all, in the birds and the bees. Especially bees. They play a critical role in the pollination game.
In the fall, when the first cold front barrels through Florida, an orange tree stops growing, setting the stage for reproduction. Rain and a patch of warm water inspire the creation of a bud.
Now here come the bees, those picky eaters, who prefer certain citrus blossoms over others. What gives certain orange blossoms the right stuff? Why do bees act as if Temple orange blossoms taste like leftover broccoli?
"It isn't the fragrance," Rouseff says. It's the size. A larger citrus blossom is more visible. It also contains more nectar. To a bee, a big flower is a brewery, a small flower a shot glass of beer.
The information becomes important in the spring, when growers often import bees into their groves for pollination. Knowing bee preferences, growers can postion hives so bees have to fly past small-blossomed trees first.
"Isn't the world wonderful?" asks Rouseff. "It's really neat to find out something new."
When he takes a deep breath in a grove full of orange blossoms, the left side of his brain, the analytical side, recognizes linalool, esters and maybe a dozen more volatiles. But the right side of his brain, the romantic's side, delivers a different message.