Adulteration Control of Honey
Using Modern Separation and Spectroscopy Techniques in Combination with Chemometrics
The control of honey purity has attracted numerous researchers the last years since honey still remains, at an international level, a beloved foodstuff. Separation and spectroscopy techniques such as gas chromatography (GC), gas chromatography coupled to mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), high performance liquid chromatography coupled to mass spectrometry (HPLC-MS), thin layer chromatography (TLC), nuclear magnetic resonance (NMR), inductively coupled plasma optical emission spectroscopy (ICP-OES), isotope ratio mass spectrometry (IRMS), middle infrared spectroscopy (MIR), etc., have gained preference among researchers during the analysis of different foodstuffs, due to the complete characterization of the product’s composition and structure, computation, along with the time of analysis and data handling . The recent years, three-dimensional fluorescence spectroscopy (3DFS) has been used for the determination of phenolic fingerprint of pure honey  and adulterated honey with rice syrup . In cases of adulteration the ‘’unique’’ structural fingerprint of honey and its properties are violated.
Cheap producing countries are pressuring more and more the market with honey being adulterated with starch, cane sugar, beet sugar, rice syrup, corn syrup, high fructose corn syrups (HFCS), or any other artificial sweetener. High-fructose corn syrup (HFCS) is a type of artificial sugar made from corn syrup. Many experts have stated that sugar and HFCS are the key factors in today‘s obesity epidemic. HFCS and sugar are also linked to many other serious health issues, including diabetes and heart disease [4,5]. In contrast, the fructose from high fructose corn syrup or table sugar needs to be converted to fat or glycogen (stored carbohydrates) by the liver before it can be used as a fuel for biochemical reactions. Therefore, HFCS adds excessive amounts of fructose to the diet, which the human body has not evolved to handle it beneficially.
Therefore, the analysis of honey, especially in the light of “honey“ being adulterated with artificial sweeteners, imported from cheap producing countries and any other countries with no evidenced practices for pure honey production, is in the spotlight of research.
Some decisive strategies for the adulteration control of honey may include:
- NMR and IRMS analyses for the detection of addition of sugar syrups, including inappropriate bee feeding, based on a multitude of markers and patterns
- Verification of botanical variety and geographical origin through the use of NMR or IRMS in combination with sophisticated statistical analyses.
At this point it should be stressed that sophisticated chemometrics may be categorized to supervised and non-supervised techniques. The analyst must use the appropriate statistical analysis with respect to the purpose of analysis. For example. if a set of variables, often termed as markers, are applied for the classification of some given factor parameters (i.e. geographical or botanical origin, pure honey or adulterated honey, etc.), then classification techniques like linear discriminant analysis (LDA), k-nearest neighbors (KNN), soft independent modeling of class analogy (SIMCA), partial least square-discriminant analysis (PLS-DA) should be used . Non-supervised techniques such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) should be applied for a quick explanation of the total variance of given groups with respect to specific markers. These techniques have visualizing capabilities .
- NMR, HPLC or HPLC-MS analyses alone or in combination, for the simultaneous identification and absolute quantification of compounds like sugars, acids, amino acids and fermentation parameters, which give information about the quality of the honey. For example, detection of deviations of the NMR profile compared to reference profiles or isotopic spectra compared to those of pure honey, may accurately quantify the detection of the fraud even in early stage.
- 3DFs analysis in combination with chemometrics: The more traditionally used techniques for honey control analysis such as high-performance liquid chromatography (HPLC), thin layer chromatography (TLC), or even middle infrared spectroscopy (MIR), etc., often require more time for testing/analysis, are more difficult to use, and can even damage the test material.
Based on the aforementioned, honey manufacturers, producers and researchers who want to ensure authentic honey properties and unique composition (i.e. colour, taste, volatile compounds, phytochemicals, minerals, simple sugars, organic acids, amino acids, etc.) should consider this approach.
Given the fact that most consumers enjoy honey for its sweet taste, and maybe even its nutritional properties, this nectar byproduct of the honeybees is always in high demand at the developed countries. With a product of high demand usually comes the undesired adulteration. As a defense against shady suppliers who might adulterate honey with rice syrup, HFCS and any other artificial sweetener, the honey ‘’shield’’ of the proposed strategies would definitely protect pure honey production and assist in the livelyhood of pure honey marketing.
Dr. Ioannis K. Karabagias
University of Ioannina
 Karabagias, I.K., Casiello, G., Kontakos, S., Louppis, P.A., Longobardi, F., Kontominas, M.G. (2016). Investigating the impact of botanical origin and harvesting period on carbon stable isotope ratio values (13C/12C) and different parameter analysis of Greek unifloral honeys: A chemometric approach for correct botanical discrimination. International Journal of Food Science and Technology, 51, 2460-2467.
 Sergiel, I., Pohl, P., Biesaga, M., Mironczyk, A. (2014) Suitability of three-dimensional synchronous fluorescence spectroscopy for fingerprint analysis of honey samples with reference to their phenolic profiles. Food Chemistry, 145, 319-326.
 Zhao, J.-W., Han, X.-Y., Chen, Q., Ouyang, Q. (2013). Identification of adulterated honey based on three-dimensional fluorescence spectra technology. Spectroscopy and Spectra Analysis, 33(6), 1626-1630.
 Ludwig, D.S., Peterson, K.E., Gortmaker, S.L. (2001). Relation between consumption of sugar-sweetened drinks and childhood obesity: a prospective, observational analysis. Lancet, 17(357), 505-508.
 Malik VS, Popkin BM, Bray GA, Després JP, Willett WC, Hu FB. (2010).Sugar-sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta-analysis. Diabetes Care, 33(11), 2477-2483.
 Zielinski, A.A.F., Haminium, C.W.I., Nunes, C.A., Schnitzler, E., van Ruth, S.M., & Granato, D. (2014). Chemical composition, sensory properties, provenance, and bioactivity of fruit juices as assessed by chemometrics: A critical review and guideline. Comprehensive Reviews in Food Science and Food Safety, 13, 300-316.
 Fernández-Torres, R., Pérez-Bernal, J.L. Bello-López, M.A. Callejón-Mochón, M., Jiménez-Sánchez, J.C., Guiraúm-Pérez, A. (2005). Mineral content and botanical origin of Spanish honeys. Talanta, 65, 686–691.