Authenticating Honey with High-Performance Thin Layer Chromatography

A recent study conducted by the University of Western Australia (Perth, Australia) and The Cooperative Research Centre for Honey Bee Products (Yanchep, Australia) and published in PeerJ Analytical Chemistry presented a high-performance thin layer chromatography (HPTLC)-based authentication system that allowed researchers to trace six key marker compounds present in Jarrah flower nectar and Jarrah honey (1,2). This authentication approach allows for the scientific characterize typical physicochemical characteristics of Jarrah honey for the first time, as well as offers a method to assist governing bodies to establish new standards so as to identify uniformed honey types for accurate labelling.

Jarrah (Eucalyptus marginata) is a dominant forest tree common to the southwestern portion of Western Australia (WA). The article states that honey resulting from the collection of its nectar is appreciated for its taste, golden color, slow crystallization, and high levels of bioactivity; this honey has been found to have many health-affirming properties, with positive identification of the nectar indicating high antibacterial activity, low glycaemic index, and high antioxidant activity. These factors have placed Jarrah in the premium product range, and, as such, the authors state that authentication is vital to protect consumers from mislabeling or adulteration, yet, prior to their research, difficult to determine.

The paper states that the advantage of using a unique HPTLC signature derived from the honey’s organic extract is that the HPTLC-derived signature of the organic extract, unique to each honey type, can be established and visually interpreted based on typical banding patterns and respective band colors, thus enabling the use of this signature for honey-type authentication without complete chemical identification of each of the bands being necessary. Compound identification, as has already been undertaken as part of their study, will further assist in authentication efforts, as well as provide insight into the potential effects of honey ripening on its chemical composition compared to the nectar resource.

To assist with the characterization of Jarrah honey, the report states that a range of physicochemical tests following Codex Alimentarius guidelines were performed. A blend of authenticated Jarrah honey samples was used to define the properties of this honey type; the blend was found to have a pH of 4.95, an electric conductivity of 1.31 mS/cm and a moisture content of 16.8%. Its water-insoluble content was 0.04%, its free acidity 19 milli-equivalents acid/kg and its diastase content 13.2 (DN). It also contains fructose (42.5%), glucose (20.8%), maltose (1.9%) and sucrose (<0.5%). The findings indicate that four of the markers traced were confirmed to be epigallocatechin, lumichrome, taxifolin, and o-anisic acid, with two (Rf 0.22 and 0.41) still chemically unidentified (1).

The HPTLC-based authentication system proposed in this study has been demonstrated to be a useful tool for identifying Jarrah honey, and can possibly act as a template in the authentication of other honey types in the future.

References

1. Islam M. K.; Barbour E.;Locher C. Authentication of Jarrah ( Eucalyptus marginata ) Honey Through its Nectar Signature and Assessment of its Typical Physicochemical Characteristics. PeerJ. Analytical Chem. 2024, 6, e33. DOI: 10.7717/peerj-achem.33 (accessed 2024-06-20)

2. Cooperative Research Centre for Honey Bee Products Website. https://www.crchoneybeeproducts.com (accessed 2024-06-20)

Honey dripping from dipper: © phive2015 - stock.adobe.com