HPLC-DAD fingerprinting and chemical characteristics of unifloral Croatian honeys

Abstract

Monofloral honeys are products connected with defined botanic species and geographical areas. Croatia, due to its peculiar climate and specific botanical species, produces several unifloral honeys. The aim of this work was to develop a direct and accurate HPLC-DAD method to study the non volatile components of honeys in order to use the chromatographic profile as a marker of the monofloral origin of the Croatian honeys. Moreover, CIE L*C*h* (lightness, chroma, hue) chromatic coordinates, total phenols, diastase activity and 5-(hydroxymethyl) furfural (HMF) were determined. The antioxidant and antiradical activities of honeys were also evaluated with FRAP and DPPH tests, respectively [1]. Honey samples of Paliurus spina-christi, Salvia officinalis, Mentha spp., and Satureja spp. honeys selected for this investigation were obtained from professional beekeepers. The melissopalynological and sensorial characteristics were evaluated as the first step to assess the botanical origin of the monofloral honeys. HPLC-DAD fingerprinting was performed with an HPLC Varian system ProStar using a Licrocart Purosher Star RP-18e column (250×4.0mm 5µm) and samples did not need any purification step. Absorbance was recorded in the range 200–600nm and chromatograms were acquired at 280, 313 and 360nm. Chromatograms obtained for the studied Croatian monofloral honeys showed strong differences according to the botanical origin, allowing to easily discriminating the studied honeys. Also L*C*h* chromatic coordinates proved to be useful to easily discriminate the studied honeys. Mentha spp. honeys showed the highest total polyphenols amount (702.1±26.6mg/kg), antioxidant (6.47±0.59 mmol Fe2+/kg) and antiradical (1.81±0.38 mmol TEAC/kg) activities. HMF highest value was 15.1±0.7mg/kg, while the lowest diastase activity was 11.9±1.1: those values respected the legal limit fixed by the EC [2] and indicate a proper way of production and storage.