Gaëlle Daniele

Identification, quantification and carbon stable isotopes determinations of organic acids in monofloral honeys. A powerful tool for botanical and authenticity control.

RATIONALE The analytical composition and botanical origin of honey are basic data used to determine the quality of this foodstuff. Although proteins are used to characterise the analytical composition of honey, they can be eliminated during its ultrafiltration and, in the case of honeys not saturated with their own pollen, the use of proteins does not work well. As acidity is a well-known characteristic of honey and organic acids are present at around 0.5% in honey, we therefore investigated an alternative method to the protein-based White method, using organic acids as new internal standards instead of proteins. METHODS The qualitative and quantitative analyses of 14 organic acids were carried out by ion chromatography with an electrochemical detector. The (13)C/(12)C isotopic ratios of the honeys, and of the organic acids extracted from them with an anion exchange resin, were determined by isotope ratio mass spectrometry. RESULTS Gluconic acid is the predominant organic acid in honey, at between 1.8 and 12.7 g/kg. For fir honey the major acid is galacturonic acid at around 4.6 g/kg. The isotopic ratios of honeys and of their acids are strongly linked. Correlations between the δ(13)C values of the honey and the acids were significant, and better than those obtained using proteins. CONCLUSIONS This study has provided a method to differentiate honeys from seven botanical origins, based on organic acid analysis. By combining various organic acid contents and isotopic ratio values through statistical processing by Principal Component Analysis it is possible to differentiate honey samples as a function of their botanical origin.

Sugar composition of French royal jelly for comparison with commercial and artificial sugar samples

A gas chromatographic method was developed to quantify the major and minor sugars of 400 Royal Jellies (RJs). Their contents were compared in relation to the geographical origins and different production methods. A reliable database was established from the analysis of 290 RJs harvested in different French areas that took into account the diversity of geographical origin, harvesting season, forage sources available in the environment corresponding to natural food of the bees: pollen and nectar. Around 30 RJ samples produced by Italian beekeepers, about sixty-ones from French market, and around thirty-ones derived from feeding experiments were analysed and compared with our database. Fructose and glucose contents are in the range 2.3-7.8% and 3.4-7.7%, respectively, whatever the RJs origin. On the contrary, differences in minor sugar composition are observed. Indeed sucrose and erlose contents in French RJs are lesser than 1.7% and 0.3%, respectively, whereas they reach 3.9% and 2.0% in some commercial samples and 5.1% and 1.7% in RJs produced from feeding experiments. This study could be used to discriminate different production methods and provide an additional tool for identifying unknown commercial RJs.

Combination of sugar analysis and stable isotope ratio mass spectrometry to detect the use of artificial sugars in royal jelly production.

The effects of feeding bees artificial sugars and/or proteins on the sugar compositions and 13C isotopic measurements of royal jellies (RJs) were evaluated. The sugars fed to the bees were two C4 sugars (cane sugar and maize hydrolysate), two C3 sugars (sugar beet, cereal starch hydrolysate), and honey. The proteins fed to them were pollen, soybean, and yeast powder proteins. To evaluate the influence of the sugar and/or protein feeding over time, samples were collected during six consecutive harvests. 13C isotopic ratio measurements of natural RJs gave values of around −25 ‰, which were also seen for RJs obtained when the bees were fed honey or C3 sugars. However, the RJs obtained when the bees were fed cane sugar or corn hydrolysate (regardless of whether they were also fed proteins) gave values of up to −17 ‰. Sugar content analysis revealed that the composition of maltose, maltotriose, sucrose, and erlose varied significantly over time in accordance with the composition of the syrup fed to the bees. When corn and cereal starch hydrolysates were fed to the bees, the maltose and maltotriose contents of the RJs increased up to 5.0 and 1.3 %, respectively, compared to the levels seen in authentic samples (i.e., samples obtained when the bees were fed natural food: honey and pollen) that were inferior to 0.2% and not detected, respectively. The sucrose and erlose contents of natural RJs were around 0.2 %, whereas those in RJs obtained when the bees were fed cane or beet sugar were as much as 4.0 and 1.3 %, respectively. The combination of sugar analysis and 13C isotopic ratio measurements represents a very efficient analytical methodology for detecting (from early harvests onward) the use of C4 and C3 artificial sugars in the production of RJ.

Multiresidue fully automated online SPE-HPLC-MS/MS method for the quantification of endocrine-disrupting and pharmaceutical compounds at trace level in surface water

The present work describes the development and validation of a sensitive method for the determination of traces of diverse groups of pharmaceuticals and endocrine disruptors in surface water. Thirty-seven substances have been selected, including 10 pesticides, 6 hormonal steroids and assimilates, 12 pharmaceuticals, 5 alkylphenols, 1 chlorophenol and 3 other well-known human contaminants, 1 UV filter and 2 plasticisers. An automated online solid-phase extraction (SPE) is directly coupled to liquid chromatography–tandem mass spectrometry. Different SPE columns have been tested, and the injection volume has been optimised. The developed analytical methodology is based on the direct injection of 2.5 mL of water sample acidified at pH 1.6 on an Oasis HLB loading column (20 × 2.1 mm) with 5-µm particles. Then, the chromatographic separation is achieved on a Kinetex XB C18 (100 × 2.1 mm; 1.7 µm) column, and the quantification is realised in multiple-reaction monitoring mode. The online SPE step warrants minimal sample handling, low solvent consumption, high sample throughput, saving time and costs. This method allows the quantification of the target analytes in the lower ng/L concentration range, with limits of quantification (LQs) between 100 pg/L and 10 ng/L, 26 compounds having LQ lower than 1 ng/L. The monitoring of two selected MS/MS transitions for each compound allows the reliable confirmation of positive findings even at the LQ level. The developed and validated methodology has been applied to the analysis of various real samples from two French rivers. Twelve target compounds have been detected in the environmental samples, and the major pollutants are pharmaceuticals usually used by humans (paracetamol, carbamazepine, oxazepam, ketoprofen, trimethoprim). The pesticides atrazine and carbendazim have been ubiquitously detected in real samples too. Metronidazole, sulfamethoxazole and diuron were also frequently quantified in the water samples.

Standard methods for Apis mellifera royal jelly research

Royal jelly, a honey bee secretion, plays a critical role in caste determination in honey bees because it serves as the source of nutrition for young larvae destined to become queens. It is also fed to adult queens. Royal jelly possesses numerous functional properties and thus has been used as a medication, health food, and cosmetic in many countries. In this paper, we first introduce a traditional method for producing royal jelly by artificial larvae grafting and a newly developed method that does not require grafting of larvae. We describe protocols for the storage and freeze-drying of royal jelly to preserve its biological properties. Routine methods for determination of two important quality criteria, water content and trans-10-hydroxy-2-decenoic acid content, are outlined. On a dry basis, protein, carbohydrate, and fatty acids were found to be the 3 most abundant components of royal jelly. Methods for their isolation, identification, and quantification are described. Because royal jelly is susceptible to contamination with veterinary drugs and acaricides, we also describe methods for detection and quantification of some veterinary drugs and acaricides in royal jelly.

Fenoxycarb exposure disrupted the reproductive success of the amphipod Gammarus fossarum with limited effects on the lipid profile

Insect growth regulator insecticides mimic the action of hormones on the growth and development of insect pests. However, they can affect the development of non-target arthropods. In the present study, we tested the effects of the growth regulator insecticide fenoxycarb on several endpoints in the freshwater crustacean Gammarus fossarum (Amphipoda). Females carrying embryos in their open brood pouch were exposed to 50 μg L-1 fenoxycarb throughout the entire oogenesis (i.e. 21 days). After exposure, newborn individuals from exposed embryos were removed from the maternal open brood pouch for lipidomic analysis, while males were added to assess the reproductive success. After fertilization, the lipid profile, energy reserve content (lipids, proteins and glycogen), and activity of phenoloxidase − an enzyme involved in the immune response − were measured in females. No significant effect of fenoxycarb exposure was observed on the lipid profile of both newborn individuals and females, while reproductive success was severely impaired in exposed females. Particularly, precopulatory behavior was significantly reduced and fertilized eggs were unviable. This study highlighted the deleterious effects of the insect growth regulator fenoxycarb on gammarid reproduction, which could have severe repercussions on population dynamics.