The Columbus Dispatch By Dominic Binkley August 31, 2014
Researchers put honey under the microscope to unlock the secrets of this complex food
Transforming nectar into sweet honey is a tireless process that calls for incredible teamwork among bees.
That and a lot of vomiting. (But more on that later.)
In honor of bees, the sweet fruit of their labor and the upcoming Lithopolis Honeyfest in Fairfield County, we are going to explore the chemistry of honey.
First, you’ve got to start with nectar, a liquid that plants produce to attract pollinators, such as bees.
Nectar is 80 percent water, colorless and slightly sweet thanks to fructose, glucose and other complex sugars, said Thomas Janini, an associate professor in Ohio State University’s College of Food, Agricultural and Environmental Sciences.
More than half of the water is lost as bees process nectar into honey, which ends up being 15 to 18 percent water, Janini said.
Although nectar’s composition varies depending on plant species and the environment, it contains some combination of amino and other acids, proteins, lipids, minerals and vitamins — ingredients that plants need to survive, said David Ball, a beekeeper and chairman of the Chemistry Department at Cleveland State University.
But sugars make up the vast majority of nectar’s ingredients and contribute to finished honey’s 83 percent sugar content. Varying combinations of sucrose, fructose and glucose make up most of nectar’s sugars and affect finished honey’s color and flavor, Ball said.
Nectar is just the raw material, though, said Janini, also a beekeeper. “When we consider honey, it’s a gross oversimplification to say that it’s just concentrated nectar. There’s a lot more going on here.”
The conversion process starts almost immediately after forager bees drink nectar from blooming plants and store it in an organ called a “crop,” or honey stomach. The organ, which is separate from the bee’s digestive stomach, can store as much as 25 milligrams of nectar until bees return to the hive.
After ingesting nectar, bees secrete enzymes, including invertase, diastase and amylase, that break down complex sugars into more easily digestible monosaccharides, or simple sugars, Janini said.
And here is where we get to the vomiting. At the entrance to a beehive, forager bees regurgitate the nectar and pass it on to house bees before heading back out for more nectar.
Enzymes are added each time nectar is ingested and regurgitated. House bees sometimes do this over and over again for as long as 20 minutes to continue breaking down the sugars, Ball said.
“Let’s face it,” he said. “Honey is bee vomit. It takes at least 100,000 vomits to make 1 pound of honey.”
Sucrose must convert into glucose and fructose, and moisture must evaporate for nectar to ripen into honey, Ball said.
House bees place the nectar in cells within the hive for one to three days until it contains about 20 percent moisture. To aid in drying, bees flutter their wings constantly to circulate air in the hive. When the moisture content decreases to less than 18 percent, bees cap the cells with wax to seal them off from additional moisture, said Barry Conrad, a Canal Winchester beekeeper.
“It’s a tough process since one bee only makes one-twelfth of a teaspoon of honey in their life,” Conrad said.