Identification Of Three Light-coloured Monofloral Honeys

Honey is a natural sweetener obtained by honey bees from nectar or honeydew and then reacted with its own substances, which is rich in both nutritional value and medicinal value. Generally speaking, the composition, color and flavor of different kinds of honey were influenced by its geographical origin and botanical origin, and these factors would have a direct impact on the nutritional value and market price of honeys. Therefore, finding and establishing a reliable and accurate identification method is very important for honey quality guarantee. There are many reports about honey species identification at home and abroad, while few researches about the identification among several monofloral honeys which were similar in color and appearance were reported. This study choose three types (linden, vicia villosa Roth honey and rape honey) of light-coloured and easily crystallized monofloral honey samples, analyzed their physicochemical parameters and the content of 14 phenolic acids, then established their chromatographic fingerprints, respectively. The floral origin of all honey samples were identified through the analyzed parameters combined with chemometrics methods. In addition, the research about rape honey added into linden and vicia villosa Roth honey were accomplished. The paper including five parts, and the contents as follows:1. More than ten kinds of physicochemical parameters (including pH, moisture content etc.) of linden, vicia villosa Roth honey and rape honey samples were determined. The identification of honey samples were carried out based on chemometrics methods. The results indicated that the physicochemical parameters of the 40 analyzed honey samples all accord with the requirements of the European Union. Although the physicochemical parameters showed certain changes along with botanical origin, the results of chemometrics showed that all honey samples could not be classified correctly based on physicochemical parameters.2. With HPLC-ECD, the content of 14 phenolic acids in honey samples were determined, meanwhile the phenolic floral origin markers were confirmed. The floral origin of honey samples were identified based on the differences of the content and types of the 14 phenolic acids in honey samples. The result shows that honey samples could be well distinguished with chemometrics methods.3. The chromatographic fingerprints of linden, vicia villosa Roth honey and rape honey samples were established, and the characteristic chromatographic peaks were selected. The floral origin of honey samples were identified based on the characteristic chromatographic peaks,40 honey samples were correctly classified. It could be conclude that chromatographic fingerprints could be used for the identification of honey types. With this method the selection of variables for the identification of honey types was more targeted, and the identities of the compounds represented by the chromatographic peaks need not be defined, so experimental process was simplified.4. The method for the identification of rape honey added into linden, vicia villosa Roth honey was established. Using Q-ToF-MS, the characteristic compounds in rape honey was determined. And the characteristic chromatographic peak was proved to be a compound with its molecular weight 362, molecular formula C16H26O9, and the maximal ultraviolet absorption value is 276.2 nm. Moreover, this compound occurred in rape honey stably, can be unacted on the influence of the geographical origin of honey samples. This research could provide the reference basis for the identification of premium quality honeys which were adulterated by rape honey.