The University of California at Riverside has collected, cultivated and cross-bred 1,000 varieties of citrus for more than a century. Manufacturers of flavorings and fragrances tap this living genetic library to come up with new product flavors.

Share story

RIVERSIDE, Calif. — Geoff Marshall-Hill finds the tango mandarin’s scent “a bit catty.” He can’t even imagine a market for the Indio mandarinquat. But the rich wine and berry undertones of the sanguinelli blood orange elicits a string of superlatives.

He wanders a dusty orchard here, about 50 miles east of Los Angeles, surrounded by co-workers who watch each morsel that goes in his mouth, and heed every bon mot that comes out. Because when it comes to taste, this 57-year-old Brit has the kind of palate that can influence the worldwide market in food and beverages.

Marshall-Hill is a principal flavorist for Givaudan, the largest manufacturer of flavorings and fragrances in the world. The Swiss company has dispatched its flavorists to jungles in Gabon and to vanilla farms in Madagascar.

But it always comes back to these 22 acres near the rocky flanks of Mount Rubidoux, which harbor a taster’s menu of the more than 1,000 varieties of citrus collected, cultivated and crossbred for more than a century by the University of California, Riverside.

It’s a living genetic library stretching from the Abhayapuri lime to the zhuluan sour orange, and in 10 years Marshall-Hill and his colleagues have sampled only about 20 percent of it.

On this day, they’ll explore about a dozen more, in search of something to pique the palates of consumers and keep the company atop one of the most opaque and cutthroat niches in the food industry.

Last year, Givaudan forked over $1 million to UC, Riverside for the privilege, creating the Givaudan Citrus Variety Collection Endowed Chair. The current occupant, Tracy Kahn, longtime curator of the collection, greets Marshall-Hill with a mother-of-pearl -handled grapefruit knife. She pares open a tango mandarin, a variety developed at Riverside that now grows on several million trees statewide.

“You probably have eaten it because this is what you find in Cutie and Halo boxes,” she explains. “Those are trademark names for what are usually multiple cultivars: clementines before Christmas — usually fina sodea clementines or clemenules — then after Christmas the W Murcott afourer and tango. But mostly tango.”

Marshall-Hill flexes the rind, releasing an oily mist below his nose, and inhales.

“This one’s quite sulfury; it’s a bit catty — cat’s pee,” he says. “Not necessarily a bad thing. It’s something you normally associate with grapefruit. Quite often with a fresh peel, it brings a very slight twinge to the profile.”

As for the fruit itself: “This is particularly succulent, particularly juicy — all the standard descriptions we’d use,” he says. “But is there anything that’s standing out? No. It’s just a really well-balanced mandarin-type profile. … This is pretty mainstream, but delicious.”

Marshall-Hill has risen over 40 years to the top tier of tasters at the top company in the field. But “I don’t consider myself a very sensitive taster,” Marshall-Hill says. “I don’t want to be a sensitive taster. Because most of the population aren’t sensitive tasters. What I think sometimes doesn’t even matter at all — it’s what consumers think.”

What consumers think about taste, though, is founded largely on misconceptions.

“To the layperson, when they’re talking about taste, they’re talking about the experience of when they eat or drink something or otherwise put it in their mouth, and that’s not just taste,” said Jeannine Delwiche, a New York-based sensory scientist and consultant who has worked in academia and industry.

When scientists talk about taste, they’re talking about an experience cobbled together as much from scent, suggestion and memory as from the nerve endings in the mouth and tongue.

“Honestly, there’s not a lot of variation in the taste compounds,” said Delwiche, who has degrees in psychology and food science. “They’re looking more at compounds that contribute to smell.”

Many of those compounds, Marshall-Hill explains, are found in the part consumers generally don’t eat: the rind. It’s his job to identify them and find ways to use them.

That exercise in molecular cuisine amounts to a $25 billion industry, led by Givaudan, fellow Swiss company Firmenich, New York-based International Flavor and Fragrances and Germany’s Symrise.

“We take things apart, play with them and build it back again,” Marshall-Hill says. “Nature gets it every day. We try in our own way to do something that approaches that, in however clumsy a way that we can.”

This year, the spice company McCormick has predicted the more adventurous consumers will veer toward tropical Asian flavors, heat and tang combinations and mixed drinks inspired by culinary techniques, such as pickling, roasting or caramelizing.

But while one consumer may reach for a peach and vanilla brûlée mixed drink that harks back to a vacation, another may just want to quaff an orange soda recalled from childhood.

Marshall-Hill is determined to please both. He’s grateful to have 1,000 trees from which to choose.