French researchers have developed a test to distinguish 100 per cent natural honeys from fake products adulterated with other substances, reports the Journal of Agricultural and Food Chemistry.
The high price and limited supply of honey has tempted some beekeepers and food processors to sell impure honey containing inexpensive sweeteners, such as corn syrup, inverted syrups and high fructose corn syrup, claims one of the researchers Bernard Herbreteau. Adulterated honey is almost indistinguishable, physically and chemically, from the real thing.
But Herbreteau and his colleagues say their highly sensitive test can put an end to fraudulent honey sales. It uses a special type of chromatography to separate and identify complex sugars or polysaccharides according to their characteristic chemical fingerprints.
The scientists obtained three different varieties of pure honey from a single beekeeper and then prepared adulterated samples of the honeys by adding 1 per cent corn syrup.
Chemical processes were used first to remove monosaccharides and small oligosaccharides and second to concentrate traces of polysaccharides.
Next the researchers achieved chromatographic separation using anion exchange stationary phase and pulse amperometric detection.
Polysaccharide fingerprints were shown to be present in adulterated samples of honey but were undetectable or present at very low concentrations in the authentic honey samples.
These differences in sugar content allowed researchers to distinguish between the pure honeys and the samples contaminated with corn syrup.
The honeys used in the tests, acacia, mountain polyfloral and polyfloral, were supplied by beekeepers from the France Honey Cooperative.
The corn syrup used to adulterate the honey samples contained 10 per cent fructose, 45 per cent glucose, 30 per cent maltose, 13 per cent maltotriose and 2 per cent higher oligosaccharides. The syrup was stored at room temperature and preserved sheltered from the light until required for analysis.
According to the scientists’ report: “…the developed analytical method allowed detection of the addition of corn syrup at the 1 per cent level in all three floral types of honey considered. Therefore, the analysis of polysaccharides will be a simple and efficient tool for honey quality control and detecting product adulteration.”
Meanwhile, three men were arrested in the US last week accused of faking the origin of imported Chinese honey to avoid paying millions of dollars in antidumping tariffs.
The case is the second within a year involving charges of false labeling of Chinese honey.