The Technique That Can Distinguish Up-Market Floral Honey
The method knows its blueberry honey from its clover honey.
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All honey is made by bees, but that doesn’t mean it’s all uniform. To produce the golden syrup, bees gather pollen from countless different species of flower. As such, most honey sold around the world can be considered poly-floral.
Some up-market producers, however, claim their honey is mono-floral – made from pollen predominantly sourced from the same species of flower. Mānuka honey, made from the pollen of the New Zealand mānuka tree, is one of the more notable varieties sold in this high-end market, along with honey made from Scottish heather, buckwheat, clover and blueberry plants.
But how can consumers know their expensive jar of honey is actually pure? After all, the honey market has become notorious in recent years for defrauding customers.
According to the European Commission, just under half of the commercial honey sold on the continent is fraudulent. In a report published in 2023, the governing body found that out of 320 products sourced from 20 countries, 147 (46%) contained suspicious adulterants such as syrup made from rice and wheat.
Is the high-end world of honey really above such fraud?
Fortunately, one research team has developed a test to help determine just that.
Floral honey testing
“The aim of my study was to develop a method based on liquid chromatography [LC] coupled to HRMS [high-resolution mass spectrometry] for the classification of honeys from different floral origin, including buckwheat, clover and blueberry,” said Dr. Lei Tian, a researcher at McGill University’s Department of Food Science and Agricultural Chemistry.
Speaking at Technology Networks’ Advances in Food & Beverage Analysis 2022, Tian began her presentation by busting a few myths about mono-floral honey.
“Mono-floral honey is a type of honey which has a distinctive flavor or other attribute due to its being predominantly from the nectar of a single plant species,” she said. “But we can never control a bee, [make] it focus on one flower or one type of flower. This is very difficult. In fact, [it’s rare] to have 100% mono-floral honey. According to the literature, if one pollen type is representative of more than 45% of the total number of pollen in the sample, it [can be] identified as a mono-floral honey.”
With that lower-than-expected threshold in mind, Tian sourced 45 honey products, advertised as mono-floral, from a market in Montreal to use as samples for her testing method.
“I selected the mono-floral honey: blueberry buckwheat and clover,” she told the Technology Networks audience. “In total, we collected 45 honey samples, 15 for each type, and we used 30 samples to build the classification model, 10 for each type.”
Once happy with the honey, the next step was preparing the samples for floral honey testing.
“For the method to analyze the honeys,” Tian continued, “we use a dilution and injection method. It's very simple. We take 0.2 grams of honey and we dilute with acetonitrile and water mixture, [in a] one to one ratio, and then we filter the solution through the 0.22 micrometer filter. And then, for the filtrate, we further dilute it 10 times using water. And then the final solution we inject directly into the LC-QTOF-MS [liquid chromatography coupled to quadrupole time-of-flight mass spectrometry].”
Finally, once the samples were tested by the “dilute-and-shoot” method, Tian and her colleagues validated their results.
“For data treatment and interpretation for the honey classification, we acquire the data under different LC-MS conditions,” she said, “because one of our objectives in the present study was to find the best working condition to study honey.”
“And then, for data processing, we have different steps to select the feature list, which is used to build the models for the honey botanical classification. For data analysis, we build the classification model with different samples selected. And then, for data interpretation, we classify the honey and check the impact of the different LC-MS conditions on the data quality we acquired.”
The bees’ tease
Honey is one of the most counterfeited foods on the market. A substantial portion of these adulterated products comes from China, according to the Honey Authenticity Network. Given that country-of-origin labeling is not required by most regulators for a product blended from elements sourced from more than one country, many shoppers will be unaware that their honey is Chinese and potentially less pure than advertised.
In her study, published in Analytica Chimica Acta in 2024, Tian reports that her “dilute-and-shoot” method successfully distinguished all the buckwheat, clover and blueberry honeys. Indeed, the total ion chromatograms (TICs) recorded were so precise that the team observed an additional signifier in the blueberry honey: a unique TIC peak with a retention time of 2.88 minutes.
With its efficacy now proven, Tian says her “relatively fast, simple method” is ready to be further improved by other researchers and analysts within the food sector, for the future development of “advanced predictive models for honey botanical origin.”
Before long, the method could be central to any new floral honey testing required by regulators. Until then, consumers of blueberry honey will just have to have a little faith in their brand of choice.
