Determination of honey botanical origin: problems and issues

International audienc

Bibliographical review of the main European unifloral honeys

International audienc

Physico-chemical methods for the characterisation of unifloral honeys: a review

International audienc

Invertase activity in honey

The invertase activity was determined for 499 honeys (27 multifloral and 472 unifloral from Arbutus, Carduus, Castanea, Citrus, Erica, Eucalyptus, Hedysarum, Helianthus, Rhododendron, Robinia, Rosmarinus, Taraxacum, Thymus, Tilia, fir honeydew and honeydew produced by Metcalfa pruinosa), in order to determine its variability and establish the range characteristic for each honey type. The results show that invertase activity varies considerably in the different honey types (from less than 0.5 to more than 30 IN). Robinia, Arbutus, Citrus, Erica and Rosmarinus have the lowest values (usually less than 10) and the two honeydew honeys the highest (more than 18). The diastase content of the samples was also measured, to compare the content of the two enzymes, and a certain correlation was observed (r = 0.835, P < 0.001). The IN/DN ratio ranges from less than 0.1 to more than 2. The possible role of invertase and IN/DN ratio in honey quality evaluation is discussed. © Inra/DIB/AGIB/Elsevier, Pari

EFFECTS OF ARTIFICIAL SUGAR FEEDING ON SUGAR COMPOSITION OF ROYAL JELLY 1

Abstract The aim of this research is to contribute to the knowledge of the Royal Jelly (RJ) sugar composition and to examine i ts possible dependence on artificial sugar feeding of bee colonies. For organic beekeeping artificial nutrition is not allowed, except in case of danger to the life of the colony. This restriction does not seem to be important for the production of RJ, which is a honeybee secretion and should not be directly affected by feeding. In this study the sugar content was determined in 95 RJ samples, partly obtained from colonies fed with different sugar syrups, partly purchased from commercial producers and importers. Results show that no correlation can be established between the RJ sugar content and the feeding regimes tested. The ranges (g/100g of fresh matter) found for the three main RJ sugars are 2.3-6.9 for fructose; 3.7-8.2 for glucose, &lt;0.1-2.1 for sucrose and 6.9-16.0 for their sum. These values may represent a contribution in establishing a quality standard for RJ

Methyl anthranilate in Citrus honey. Analytical method and suitability as a chemical marker

The present work describes a method for the determination of methyl anthranilate (MA) in honey, and reports the results of a study carried out on 46 Citrus honey samples produced in different countries. The MA content was measured, and the compliance of the samples with the unifloral Citrus honey profile was verified, according to the traditional authenticity parameters (physicochemical, sensory and microscopic). The analytical results show that MA values do not significantly differ in unifloral and not unifloral samples. More generally, no relationship could be found between MA content and the level of uniflorality or any single authenticity parameter. The conclusion is that MA content can not be used as a discriminating parameter for Citrus honey, and should be used only as a further descriptive element. Among the unifloral samples the MA content was lower in those produced in Italy than in the other countries, and mostly below the 2 mg/kg limit that some European laboratories require to accept Citrus honey

Venezuelan stingless bee honeys characterized by multivariate analysis of physicochemical properties

Stingless bee honey samples collected from 27 nests in Venezuela, were analysed for ten compositional factors (acidity, ash, electrical conductivity, diastase activity, hydroxymethylfurfural, invertase activity, nitrogen, reducing sugars, sucrose and water). The entomological origin of the honeys based on these factors was explored using three methods of multivariate analysis. Clustering was adequate to separate the honey samples into two stingless bee tribes with the exception of honeys from one genus ofTrigonini. Principal component analysis confirmed these findings and grouped the honeys to species level. Although discriminant analysis of the ten quality factors under consideration positioned all the samples in their respective entomological group, lowering the number of variables to reducing sugars, sucrose and diastase activity was still satisfactory for a correct classification. A fourth variable that could be used to assign correct membership was either acidity or nitrogen content. © Inra/DIB/AGIB/Elsevier, Pari