International audienc

No abstract

The validation of rapid, low-cost spectrophotometric procedures for the quantification of the three main groups of bioactive substances (flavones and flavonols, flavanones and dihydroflavonols, and total phenolics) in poplar-type propolis has been performed. A spectrophotometric assay based on the formation of an aluminium chloride complex was applied for the quantification of total flavones and flavonols using galangin as standard. Because of the high amount of flavanones and dihydroflavonols in "poplar type" propolis, the introduction of a distinct procedure for their quantification was considered of special significance and the DAB9 colorimetric method was applied for the purpose. Total phenolic content was measured by the Folin-Ciocalteu procedure using a mixture of pinocembrin and galangin as a reference. The procedures were validated using a model mixture of compounds representing the poplar-type propolis composition as found in previous studies. The accuracy (recovery) varied in the range 84-109%, and the relative standard deviation was 0.5-6.2%. The developed spectrophotometric procedures were applied to six poplar type propolis samples. The results were verified independently by a HPLC procedure. The two sets of results agreed satisfactory, as proven by Student's t-test.

No abstract

Summary — The characterization of 14 types of Italian unifloral honeys was carried out on the basis of the organoleptic, microscopic (qualitative and quantitative melissopalynological analysis) and physicochemical properties (colour, moisture, ash, HMF, diastase, pH, total acidity, electrical conductivity, specific rotation and sugars). The botanical origins of the examined honeys were Arbutus unedo

The recent availability of the honey-bee Apis mellifera genome and trascriptome of both the female castes, has stimulated new efforts in investigating the protein composition of royal jelly (RJ), its role in caste differentiation and its quality and typicality by a proteomic approach. This study is aimed both to separate and identify proteins of royal jelly and to detect some of them in honey-bee pollen-bread by using two-dimensional gel electrophoresis, mass spectrometry and by de novo sequencing. All the identified proteins belonged to the Apis mellifera genome. Apalbumin 1 was also confirmed to be present in honey-bee pollen-bread where the presence of apalbumin 2 was also found. In addition several fragments of apalbumin 1 and apalbumin 3 were also found in RJ. These could be the result of protease activity other than that of serine-protease. This study is a contribution to the description of royal jelly proteome.

With the objective of finding floral markers for the determination of the botanical origin of acacia (robinia) honey, the phytochemicals present in nectar collected from Robinia pseudacacia flowers were analyzed by high-performance liquid chromatography-tandem mass spectrometry. Eight flavonoid glycosides were detected and characterized as kaempferol combinations with rhamnose and hexose. Acacia honey produced in the same location where the nectar was collected contained nectar-derived kaempferol rhamnosides. This is the first time that flavonoid glycosides have been found as honey constituents. Differences in the stability of nectar flavonoids during honey elaboration and ripening in the hive were shown to be due to hydrolytic enzymatic activity and to oxidation probably related to hydrogen peroxide (glucose-oxidase) activity. Acacia honeys contained propolis-derived flavonoid aglycones (468-4348 microg/100 g) and hydroxycinnamic acid derivatives (281-3249 microg/100 g). In addition, nectar-derived kaempferol glycosides were detected in all of the acacia honey samples analyzed (100-800 microg/100 g). These flavonoids were not detected in any of the different honey samples analyzed previously from different floral origins other than acacia. Finding flavonoid glycosides in honey related to floral origin is particularly relevant as it considerably enlarges the number of possible suitable markers to be used for the determination of the floral origin of honeys.

-Free amino acids (FAAs) in royal jelly (RJ) were determined and their identification was confirmed with mass spectrometric detection (GC-MS). The presence of D-aminoacids was evaluated using GC with a chiral column. The total FAA content was 7.3 mg/g RJ on average; the major FAAs were proline, lysine, glutamate, β-alanine, phenylalanine, aspartate and serine. The concentration of FAAs of the D-series was below the detection limit of the method (0.1 mg/g RJ) in all the samples. The FAA fraction was monitored in RJ frozen immediately after sample collection (control) and in aliquots of the same sample stored at two different temperatures (room temperature and 4 °C) for different time intervals (3, 6 and 10 months). The FAA content was constant throughout storage at 4 °C. However, at room temperature, proline and lysine increased after three months to 6.8 and 3 mg/g, respectively and then decreased after 6 and 10 months to 3 and 1 mg/g. royal jelly / free amino acid / storage condition / gas chromatography-mass spectrometry / chiral separation