Suitability of antioxidant capacity, flavonoids and phenolic acids for floral authentication of honey. Impact of industrial thermal treatment.

Total antioxidant activity, physicochemical parameters, and the profile of flavonoids and phenolic acid compounds were evaluated for: their ability to distinguish between the botanical origins of four types of Spanish honey, the impact of industrial thermal treatment, and the effect of the year of collection. Citrus honey had the lowest levels of all the analysed variables, then rosemary and polyfloral, and honeydew the highest ones. Botanical origin affects the profile of flavonoids and phenolic compounds sufficiently to permit discrimination thanks to the predominance of particular compounds such as: hesperetin (in citrus honey); kaempferol, chrysin, pinocembrin, caffeic acid and naringenin (in rosemary honey) and myricetin, quercetin, galangin and particularly p-coumaric acid (in honeydew honey). The impact of industrial thermal treatments is lower than the expected variability as a consequence of the year of collection, though neither factor has enough influence to alter these constituent compounds to the point of affecting the discrimination of honey by botanical origin.

Volatile fraction composition and physicochemical parameters as tools for the differentiation of lemon blossom honey and orange blossom honey.

BACKGROUND: Volatile fraction profile and physicochemical parameters were studied with the aim of evaluating their effectiveness for the differentiation between lemon blossom honey (Citrus limon L.) and orange blossom honey (Citrus spp.). They would be useful complementary tools to the traditional analysis based on the percentage of pollen. RESULTS: A stepwise discriminant analysis constructed using 37 volatile compounds (extracted by purge and trap and analysed by gas chromatography-mass spectrometry), and physicochemical and colour parameters (diastase, conductivity, Pfund colour and CIE L a b) together provided a model that permitted the correct classification of 98.3% of the original and 96.6% of the cross-validated cases, indicating its efficiency and robustness. This model proved its effectiveness in the differentiation of both types of honey with another set of batches from the following year. CONCLUSION: This model, developed from the volatile compounds, physicochemical and colour parameters, has been useful for the differentiation of lemon and orange blossom honeys. Furthermore, it may be of particular interest for the attainment of a suitable classification of orange honey in which the pollen count is very low. These capabilities imply an evident marketing advantage for the beekeeping sector, since lemon blossom honey could be commercialized as unifloral honey and not as generic citrus honey and orange blossom honey could be correctly characterized.