Hervé Casabianca

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

RATIONALEnThe 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.nnnMETHODSnThe 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.nnnRESULTSnGluconic 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.nnnCONCLUSIONSnThis 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.

Trace-level determination of pyrethroid, neonicotinoid and carboxamide pesticides in beeswax using dispersive solid-phase extraction followed by ultra-high-performance liquid chromatography-tandem mass spectrometry

The aim of the work was to develop an analytical procedure able to quantify traces of 13 neonicotinoids and pyrethroids as well as carboxamide in beeswax at low levels (ng g−1) to evaluate the contamination. For this purpose, an efficient sample preparation procedure was developed based on solid–liquid extraction using dispersive diatomaceous earth and acetonitrile. This step was followed by a selective and sensitive analysis based on ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (ESI-MS/MS). This analytical procedure was validated based on International Conference on Harmonization guidelines. The limits of quantification ranged from 1 ng g−1 (thiamethoxam, clothianidin, imidacloprid, acetamiprid, thiacloprid and boscalid) to 40 ng g−1 (lambda-cyhalothrin). The method was then successfully applied to 60 samples of beeswax collected in several areas of France. The presence of thiacloprid, boscalid, imidacloprid and deltamethrin in beeswax was confirmed. The most frequently quantified pesticide was boscalid.

Phytochemical and Biological Investigation of Two Diplotaxis Species Growing in Tunisia: D. virgata & D. erucoides

A phytochemical investigation of Diplotaxis virgata D.C. and D. erucoides (L.) D.C. (Brassicaceae) offered to the isolation of two new flavonoids isorhamnetin-3-O-α-l-glucopyranoside (1) and rhamnetin-3,3ʹ-di-O-β-d-glucopyranoside (2), respectively. Their structures have been elucidated from the extended spectroscopic methods, including 1D- and 2D-NMR, UV and mass spectrometry analysis and by comparison with literature data. The fatty acid composition of the hexane extracts of the two species was also investigated by using GC-MS. The antioxidant activity of ethanol, ethyl acetate, n-butanol extracts and the isolated compounds from the two species was evaluated using DPPH and ABTS+ scavenging assays. All the tested samples showed an efficient radical scavenging ability, with IC50 values ranging from 16–40 µg/mL for the DPPH and from 17–44 µg/mL for the ABTS+ assays. In addition, the antibacterial activity of the prepared extracts and compounds 1 and 2, determined by well diffusion agar method against two Gram positive and five Gram negative bacteria, was evaluated and the results showed significant effects against all strains used.

Chemical Composition of Cyperus rotundus L. Tubers Essential Oil from the South of Tunisia, Antioxidant Potentiality and Antibacterial Activity against Foodborne Pathogens

Abstract The chemical composition of Cyperus rotundus L. tubers essential oil from the South of Tunisia was analyzed using GC-FID and GC-MS. Fifty compounds were identified representing 84.6% of the total oil. A new chemotype was found in Tunisia. This essential oil was characterized by sesquiterpenes abundance (78.3%) mainly represented by cyperene (15.2%) and cyperotundone (19.7%). The essential oil (EO) was further fractionated into three fractions (F1: n-pentane, F2: n-pentane/diethyl ether (95/5) and F3: diethyl ether). The antioxidant activity of the EO and its fractions was tested using the1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test and β-carotene bleaching method. Results showed that the whole EO was more active than the fractions with an effective concentration (EC) of 0.85 ± 0.03u2005mg/mL and an antioxidant activity coefficient (AAC) of 396.0 ± 2.4. The antimicrobial activity of the EO and its fractions was evaluated using the disc diffusion method against six foodborne pathogens and results showed that Staphylococcus aureus was the most inhibited bacterium with an inhibition diameter of 15.2 ± 0.8u2005mm for the whole EO.

Characterization of surfactant complex mixtures using Raman spectroscopy and signal extraction methods: Application to laundry detergent deformulation.

This paper presents the analysis of surfactants in complex mixtures using Raman spectroscopy combined with signal extraction (SE) methods. Surfactants are the most important component in laundry detergents. Both their identification and quantification are required for quality control and regulation purposes. Several synthetic mixtures of four surfactants contained in an Ecolabel laundry detergent were prepared and analyzed by Raman spectroscopy. SE methods, Independent Component Analysis and Multivariate Curve Resolution, were then applied to spectral data for surfactant identification and quantification. The influence of several pre-processing treatments (normalization, baseline correction, scatter correction and smoothing) on SE performances were evaluated by experimental design. By using optimal pre-processing strategy, SE methods allowed satisfactorily both identifying and quantifying the four surfactants. When applied to the pre-processed Raman spectrum of the Ecolabel laundry detergent sample, SE models remained robust enough to predict the surfactant concentrations with sufficient precision for deformulation purpose. Comparatively, a supervised modeling technique (PLS regression) was very efficient to quantify the four surfactants in synthetic mixtures but appeared less effective than SE methods when applied to the Raman spectrum of the detergent sample. PLS seemed too sensitive to the other components contained in the laundry detergent while SE methods were more robust. The results obtained demonstrated the interest of SE methods in the context of deformulation.

New biosourced AA and AB monomers from 1,4:3,6-dianhydrohexitols, Isosorbide, Isomannide, and Isoidide

Abstract In the present work, we propose the synthesis of a new family of sugar derived 1,4:3,6-dianhydrohexitol based AA/AB-type monomers. Unprecedented diacids based on Isomannide and Isoidide were elaborated with high yields and showed interestingly high melting point ranges (240–375 °C). Optimization of reaction conditions (temperature, time of reaction, and reactant ratios) has been investigated to synthesize the key intermediate of a set of AB monomers with acid, ester, and acid chloride functionalities. Isosorbide based ether benzoic acid AB monomer was polymerized and characterized by NMR and DSC techniques. The results show a semicrystalline behavior of the obtained polymer thanks to the controlled stereoregular arrangement of the AB starting monomer.

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.

Effect of acid hydrolysis on alizarin content, antioxidant and antimicrobial activities of Rubia tinctorum extracts

Purpose n n n n nThe paper aims to analyse the effect of acid hydrolysis on the chemical composition and the biological activities of Rubia tinctorum collected from the south of Tunisia. It proposes to clarify the relationship between alizarin content and the antioxidant and antimicrobial activities of Rubia extract. n n n n nDesign/methodology/approach n n n n nThe paper opted for analytical tools (HPLC) and the in-vitro study of biological activities, namely, the antioxidant activity which is evaluated using the radical scavenging assay (ABTS) and ferric reducing power assay (FRAP); the antimicrobial activity is tested using the wells agar diffusion method. n n n n nFindings n n n n nThe paper provides information about the positive effect of acid hydrolysis, namely, the enhancement of alizarin content in the extract which has increased its antioxidant and antimicrobial activities. n n n n nOriginality/value n n n n nThis paper fulfils an identified need to study the relationship between the chemical composition, biological activities and colour enhancement.