The original text was published in the Science and Technology Grand View Garden “High-Quality Bee Product R&D Technology Alliance – Creating Taiwan’s Top Honey Supply Chain”
“Not Pure, Cut Off!” – Are You Eating Honey or Syrup?
In recent years, food safety incidents have been frequent. Have you ever suspected that the warm and rich honey is a gift from nature, or a black-hearted miracle mixed with chemical flavorings, colorants, and syrup? Do you believe the industry’s loud cries of “Not Pure, Cut Off” or have you heard that you can guess the purity of honey by looking at the foam of honey water?
At the end of 2015, the Taipei City Health Bureau inspected 15 samples of honey claiming to be “natural,” “pure,” and “100%” but found that 3 did not meet the national standard CNS 1305. Additionally, 3 others passed the national standard but were found to have added sugars or insufficient purity through advanced carbon isotope testing. In the past few years of honey inspections, there have been numerous cases involving products or manufacturers with various certifications and awards that still tested positive for fraud or insufficient purity.
The frequent occurrence of inferior honey has hit the market and highlighted the inadequacy of existing certification standards. The causes of this situation can be seen from the characteristics and production processes of inferior honey. Currently, the fake honey on the market can be roughly divided into the following categories:
Artificial Honey and Blended Honey
Artificial honey, also known as blended honey, can be made using corn syrup, caramel color, and flavorings, resulting in a fake honey that is difficult to distinguish from real honey by taste. The cost of such fake honey is extremely low, with prices on the market only a few dozen dollars per liter.
However, the characteristics of artificial honey differ greatly from those of real honey. Most of the methods taught to the public for testing honey are aimed at this type of honey. For example, if you dilute honey with water ten times and shake it, real honey will produce a lot of foam due to the proteins it contains, and this foam can last for hours. But fake honey, which lacks proteins, will have foam that dissipates very quickly. Although artificial honey can also achieve a similar effect by adding proteases, it is difficult to pass various tests due to the presence of colorants and flavor additives, often flowing through food material channels that do not directly face consumers.
Factory Blending
The second type of inferior honey that is harder to distinguish is “factory blending.” Factory blending occurs when natural honey is sent to a concentration factory for processing, where it is diluted with high fructose syrup or mixed with cheaper honey from other countries. By adding starch enzymes and other natural honey components, it can pass the CNS-1305 national inspection standards. Without advanced carbon isotope testing, it is even more challenging to determine the authenticity of the honey.
Syrup Residue
Another type of inferior honey that can be identified is related to the characteristics of the beekeeping industry. For the beekeeping industry, the period from March to May each year is crucial for honey production. Therefore, before the arrival of March, beekeepers will feed sugar water to the bees to fatten them up. When the flowers bloom, the bees produce the first batches of honey, which will contain a higher proportion of sugar fed to them rather than flower nectar. However, if the flowering period is unstable or the quality of the flowers is not ideal, beekeepers will intentionally feed sugar water to increase honey production.
The honey produced in this way does not have additional processing or other additives. Although it is harmless to the human body, it does not come from plant flower nectar and lacks the organic acids and enzymes derived from flowers. It also does not meet today’s definition of honey as “a natural sweet substance collected by bees from plant flower nectar or honeydew, transformed, stored, and dehydrated by bees into mature honey.”
Identifying Fake Honey with Food Science
In terms of honey testing, various countries have proposed and applied related technologies over the years, such as using gas chromatography (GC) and liquid chromatography (LC) to detect the content and ratio of various monosaccharides in honey [1]; using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to test the content of various oligosaccharides in honey [2]; or using near-infrared spectroscopy (NIRS) to compare the changes in components after honey adulteration [3].
Professor Chen Yu-wen’s team from National Ilan University: From left to right are Chen Chun-ting (PhD student), You Ya-gen (assistant), Professor Chen Yu-wen, Chen Liang-yuan (Master’s student), and Chen Yi-cheng (Master’s assistant).
The Weapon to Differentiate Honey from Syrup – Carbon Isotope Analysis
Since 2012, Professor Chen Yu-wen’s team at National Ilan University has established a stable carbon isotope ratio analysis technique (SCIRA). This technique compares the ratio of carbon isotopes 13C and 12C in the test sample (honey) to infer whether there is a possibility of fraud or impurity in the honey’s composition or source. The differences in carbon isotope composition arise because different types of plants use different forms of photosynthesis, leading to different carbon isotope differentiation. For example, crops like corn and sugarcane use the C4 photosynthetic pathway, resulting in a higher 13C isotope; while rice, beets, cassava, and most nectar plants use the C3 photosynthetic pathway, which has a higher proportion of 12C isotopes. Since fake honey syrup is often made from high fructose corn syrup or sucrose, measuring the carbon isotope ratio in honey can help infer the presence of adulteration or impurity.
The results of carbon isotope analysis can be expressed by calculating the δ13C value of the ratio of 13C to 12C:
If the honey source is from C4 plant syrups like sugarcane or corn, the δ13C value will range from -9 to -15‰; but for pure honey from nectar plants, the δ13C value should be between -23 and -28‰. Therefore, if the measured value falls between these two ranges, it is highly likely that the honey has been diluted with syrup or produced from bees intentionally fed sugar water.
To obtain more accurate results, the research team further separated the proteins in honey using the method specified by the International Association of Official Chemists (AOAC Official Method 998.12, 2005), and then calculated the difference between honey protein and honey δ13C. Past studies have indicated that if the difference exceeds 1.0‰, it is likely that the honey has been adulterated with artificial syrup [4-5]. Further calculations can be made with the ratios of honey protein to the difference from artificial C4 syrup:
Since the proteins in natural honey share the same source as the honey, the closer the two δ13C values are, the higher the purity of the honey. A comparison with an artificial C4 syrup as a baseline (δ‰(sweetener) = -9.7) shows that if %Adulteration exceeds 7%, it indicates that the tested honey contains excessive syrup or that the main source of the honey is sugar water rather than nectar. Professor Chen Yu-wen’s team used this method to sample 62 honey products on the market and found that 32 of them met the adulteration standards.
Characterizing Honey Flavor with Unique Fingerprints – GS-IMS Gas Chromatography
SCIRA technology can accurately identify inferior honey mixed with sucrose and corn syrup, as well as honey that has been excessively or intentionally fed sugar water. However, unscrupulous operators can still use artificial C3 syrup made from cassava starch or mix in cheaper honey imported from other countries to gain improper benefits. Therefore, establishing food science technologies for origin identification has become key to ensuring honey quality.
Professor Chen Yu-wen from National Ilan University with the GC-IMS gas chromatography-ion mobility spectrometry analyzer.
Just like tasting tea or wine, honey produced from different regions, nectar sources, and bee species has different flavors, which represent differences in composition. To more accurately quantify the characteristics of honey from various regions, Professor Chen Yu-wen’s team used a Gas Chromatograph coupled to Ion Mobility Spectrometer (GC-IMS) to establish a database of honey components from different regions.
The principle of GC-IMS is to heat the honey, and the volatile organic compounds (VOCs) released during heating contain molecular clusters of different masses, leading to different diffusion distances during the volatilization process. Because the diffusion coefficient in the gas phase is much larger than in the liquid phase, it can quickly separate different molecular clusters in honey. At the same time, tritium (3H) is used to collide with the molecular clusters, causing β decay of tritium to release electrons, ionizing the molecular clusters. These ions are then passed through an electric field, and due to the different migration rates of the ions in the electric field, the time of ion drift can be used to qualitatively separate complex components.
In the results of GC-IMS testing, we can see significant differences in the component profiles of Taiwanese honey and Thai honey. The application and implementation of this technology in food safety testing will help curb the actions of unscrupulous operators who falsify origins or mix in cheap imported honey.
Professor Chen Yu-wen’s honey profile created using GC-IMS shows clear differences in the component profiles of Taiwanese honey and Thai honey.
High Standards for Honey Quality Control from Bees to Honey
Although the development of various technologies can significantly improve the quality of honey in our country, these technologies are still not widely adopted or valued in today’s market. Looking at the CNS 1305 national standards for honey in our country [6], the specifications for components such as moisture, sucrose, glucose, fructose, insoluble matter, acidity, and hydroxymethylfurfural (HMF) content to assess whether honey is fresh and of good quality can easily be passed by high fructose syrup. The activity regulations for starch enzymes can also be passed by adding starch enzymes to high fructose syrup. The current national standards may no longer serve as a basis for determining the authenticity of honey, making it necessary for consumers to rely on more labels, certification mechanisms, and trust in quality manufacturers to help them choose good quality honey.
Therefore, the “High-Quality Bee Product R&D Technology Alliance” led by Professor Chen Yu-wen not only actively and rigorously utilizes food science technologies to identify authenticity but also focuses on improving the overall industry. Currently, with the National Ilan University Bee and Biotech Health Product Center as the core, they are seeking collaboration with quality honey suppliers upstream in the supply chain, while also mediating various channels at the sales end. The National Ilan University and Taiwan SGS Inspection Technology Company provide product testing for artificial syrup, pesticide residues, antibiotics, etc., and have established standards that are more stringent than CNS 1305. Additionally, the National Ilan University Bee and Biotech Health Product Center is responsible for everything from honey sampling and testing to final bottling and sealing.
The honey collected by beekeepers is sealed with a seal after sampling by the National Ilan University team members to ensure the consistency of the sample and honey quality.
For the sampled honey, there are dedicated personnel who seal it with a seal after sampling to ensure the accuracy of the sample. Honey that has passed inspection is also bottled, sealed, and packaged by the National Ilan University. Each completed bottle of honey is given its own serial number and QR code, allowing consumers to easily trace the production and inspection data of each bottle of honey. From the agricultural guidance at the source of honey, food science product testing to the promotion and mediation of sales channels, the “High-Quality Bee Product R&D Technology Alliance” is redefining the complete supply chain of top-quality honey, allowing honey to shed food safety concerns and regain its precious value.
Honey that has passed inspection is handled by National Ilan University for repackaging, bottling, and sealing.
References
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Cotte, Jean-François, et al. “Application of carbohydrate analysis to verify honey authenticity.” Journal of Chromatography A 1021.1 (2003): 145-155.
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Morales, V., N. Corzo, and M. L. Sanz. “HPAEC-PAD oligosaccharide analysis to detect adulterations of honey with sugar syrups.” Food Chemistry 107.2 (2008): 922-928.
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Kumaravelu, Chellakutty, and Aravamudhan Gopal. “Detection and Quantification of Adulteration in Honey through Near Infrared Spectroscopy.” International Journal of Food Properties 18.9 (2015): 1930-1935.
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Anklam, Elke. “A review of the analytical methods to determine the geographical and botanical origin of honey.” Food chemistry 63.4 (1998): 549-562.
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Elflein, Lutz, and Kurt-Peter Raezke. “Improved detection of honey adulteration by measuring differences between 13C/12C stable carbon isotope ratios of protein and sugar compounds with a combination of elemental analyzer—isotope ratio mass spectrometry and liquid chromatography—isotope ratio mass spectrometry (δ13C-EA/LC-IRMS).” Apidologie 39.5 (2008): 574-587.
Transferred from: Pan Science