Honey as a bioindicator of environmental organochlorine insecticides contamination

Honey is a suitable matrix for the evaluation of environmental contaminants including organochlorine insecticides. The present study was conducted to evaluate residues of fifteen organochlorine insecticides in honey samples of unifloral and multifloral origins from Dir, Pakistan. Honey samples (5 g each) were extracted with GC grade organic solvents and then subjected to Rotary Evaporator till dryness. The extracts were then mixed with n-Hexane (5 ml) and purified through Column Chromatography. Purified extracts (1μl each) were processed through Gas Chromatograph coupled with Electron Capture Detector (GC-ECD) for identification and quantification of the insecticides. Of the 15 insecticides tested, 46.7% were detected while 53.3% were not detected in the honey samples. Heptachlor was the most prevalent insecticide with a mean level of 0.0018 mg/kg detected in 80% of the samples followed by β-HCH with a mean level of 0.0016 mg/kg detected in 71.4% of the honey samples. Honey samples from Acacia modesta Wall. were 100% positive for Heptachlor with a mean level of 0.0048 mg/kg followed by β-HCH with a mean level of 0.003 mg/kg and frequency of 83.3%. Minimum levels of the tested insecticides were detected in the unifloral honey from Ziziphus jujuba Mill. Methoxychlor, Endosulfan, Endrin and metabolites of DDT were not detected in the studied honey samples. Some of the tested insecticides are banned in Pakistan but are still detected in honey samples indicating their use in the study area. The detected levels of all insecticides were below the Maximum Residue Levels (MRLs) and safe for consumers. However, the levels detected can cause mortality in insect fauna. The use of banned insecticides is one of the main factors responsible for the declining populations of important insect pollinators including honeybees.

The Use of Right Angle Fluorescence Spectroscopy to Distinguish the Botanical Origin of Greek Common Honey Varieties

The standardization of the botanical origin of honey reflects the commercial value and quality of honey. Nowadays, most consumers are looking for a unifloral honey. The aim of the present study was to develop a novel method for honey classification using chemometric models based on phenolic compounds analyzed with right angle fluorescence spectroscopy, coupled with stepwise linear discriminant analysis (LDA). The deconstructed spectrum from three-dimensional-emission excitation matrix (3D-EEM) spectra provided a correct classification score of 94.9% calibration and cross-validation at an excitation wavelength (λex) of 330 nm. Subsequently, a score of 81.4% and 79.7%, respectively, at an excitation wavelength (λex) of 360 nm was achieved. Each chemometric model confirmed its power through the external validation with a score of 82.1% for both. Differentiation could be correlated with hydroxycinnamic and hydroxybenzoic acids, which absorb in this region of the spectrum. Fluorescence spectroscopy constitutes a rapid and sensitive technique, which, when combined with the stepwise algorithm and LDA method, can be used as a reliable and predictive authentication tool for honey. This study indicates that the developed methodology is a promising technique for determination of the botanical origin of common Greek honey varieties. Our long-term ambition is to support producers and suppliers to remain in a competitive national and international market.

Melissopalynological analysis of honey produced by two species of stingless bees in Lombok Island, Indonesia

Jayadi LZ, Susandarini R. 2020. Melissopalynological analysis of honey produced by two species of stingless bees in Lombok Island, Indonesia. Nusantara Bioscience 12: 97-108. Honey is a natural product with a variety of benefits that commonly used as food sweeteners, health supplements, and traditional medicine. There has been no comprehensive publication regarding the diversity of pollen contained in honey produced by stingless bee Tetragonula laeviceps and Heterotrogona itama from Lombok. This study aimed to reveal the diversity of pollen content in honey through melissopalynological analysis of honey samples produced by two species of stingless bees T. laeviceps and H. itama in Lombok Island. This melissopalynological study was performed on honey samples obtained from nine villages from nine sub-districts representing the three districts on Lombok Island. Pollen extraction from honey was carried out using standard methods for melissopalynological analysis. The diversity of pollen recovered from honey varied from 15 to 41 pollen types. Total number of plant species whose pollen was recovered from honey samples was 127 which consisted of 61 families. The occurrence of predominant pollen type in particular unifloral honey samples indicated their botanical origin and presumed geographical origin of honey. Results of this study are useful in confirming botanical origin of honey and generating information on plants potential as food source for sustainable beekeeping in Lombok Island.

Botanical Origin, Pollen Profile, and Physicochemical Properties of Algerian Honey from Different Bioclimatic Areas

The palynological and physicochemical analysis of 62 honey samples produced in different biogeographical areas of Algeria was conducted. Results showed high variety in the botanical origin of samples and their physicochemical profile. Twenty-six samples were polyfloral honey, 30 were unifloral honey from different botanical sources such as Eucalyptus, Citrus, Apiaceae, Punica, Erica, Rosmarinus, Eriobotrya, or Hedysarum, and 6 were characterized as honeydew honey. Pollen analysis allowed the identification of 104 pollen types belonging to 51 botanical families, whereas the physicochemical profile showed important variations between samples. Multivariate techniques were used to compare the characteristics of samples from different biogeographical areas, showing significant differences between humid-area samples, located in the northeast of the country, and samples taken in semiarid, subhumid, and arid zones. Principal-component analysis (PCA) extracted nine components explaining 72% of data variance, being 30%, the sum of Component 1 and Component 2. The plot of both components showed samples grouped upon botanical and geographical origin. The results of this paper highlighted the great variability in honey production of Algeria, evidencing the importance of honey characterization to guarantee authenticity and to valorize local production.

A Holistic View to Develop Descriptive Sheets for Argentinean Clover and Eucalyptus Unifloral Honey

Background: Honey is a complex natural product that varies not only in sensory properties but also in chemical composition. The apiculture industry is interested in offering unifloral honey with specific palynological, physicochemical and sensory characteristics. However, to the best of our knowledge, no proper study has been reported in Argentina in this regard so far. Objective: The aim of this study was to develop descriptive sheets analyzing and compiling previous palynological, physicochemical and sensory data obtained from Argentine eucalyptus and clover unifloral honeys. Methods: The analysis included predominant and main secondary pollens; physicochemical characteristics as moisture content, acidity, ash content, electrical conductivity, fructose, glucose, maltose and sucrose, optical rotation and colour; antioxidant indicators as DPPH, TEAC, FRAC, OH; content of phenolic and flavonoids compounds and the main sensory descriptors like colour, smell, aromatic notes, sweetness and persistence. Results: The analysis was made by gathering 30 Eucalyptus honey (Eucalyptus spp.) and 55 clover honey (Trifolium sp.). Forty-one morphological pollen types were recognized. The set of physicochemical measures for honey met quality specifications for international marketing. Colour and odour intensity, higher for eucalyptus honey, were identified as the main differentiating sensory attributes. Conclusion: An holistic analysis of all these properties allows to determine quality and certification of Argentinean eucalyptus and clover unifloral honey. The intervals of variation of selected palynological, physicochemical and sensory variables gathered in the descriptive sheets allow us to decide whether or not a sample of honey can be classified as belonging to one of these floral origins.

Melissopalynological and physicochemical analysis of honey samples from Prayagraj District, Uttar Pradesh

In melissopalynological and physicochemical analyses of 14 honey samples collected from different rural and urban localities of Prayagraj District, Uttar Pradesh, 43 pollen types were identified and categorized as predominant (above 45%), secondary (16–45%), important minor (3–15%) and minor (below 3%). Five of the 14 samples were classified as unifloral due to the presence of predominant pollen types (above 45%), and the other 9 as multifloral. Brassica campestris and Coriandrum sativum were the predominant pollen types in unifloral honey; 14 pollen types were documented in the secondary pollen types (16–45%) in multifloral honey. The analyzed physicochemical parameters included pH (mean 3.40 ± 0.15 to 4.74 ± 0.4), electrical conductivity (mean 0.13 ± 0.03 to 1.39 ± 0.17 mS/cm), total dissolved solids (120 ± 1.23 to 1260 ± 1 ppm), moisture content (12.17 ± 1.39 to 24.78 ± 1.54 mg/100 g) and ash content (0.15 ± .04 to 1.68 ± .27 mg/100g). The color of the honey ranged from water-white to dark amber. Among the minerals, magnesium was found to be most abundant (9 ± 0 to 11.8 ± 0 mg/kg), followed by iron (2.0 ± 0 to 4.8 ± 0 mg/kg) and zinc (0.39 ± 0 to 0.63 ± 0 mg/kg). The heavy metals cadmium, lead, copper and arsenic were below the limit of detection (< 0.01 mg/kg) in all honey samples except in samples H6 (Cd 0.01 mg/kg, Pd 0.27 mg/kg), H11 (Cd 0.02 mg/kg, Pd 0.05 mg/kg), H13 (Pd 0.02 mg/kg) and H14 (Cd 0.01 mg/kg, Pd 0.04 mg/kg). The physicochemical parameters varied significantly (p < 0.05) between samples. Findings of the present study indicate that the honey is of good quality and should be used in projects for commercialization of regional honey.

Cromathographic Profile of Volatiles of Multifloral and Unifloral Honey Collected by Apis Mellifera from Transilvania, Romania

Chromatographic profile of volatiles organic compounds (VOCs) from several varieties of multifloral and unifloral honey produced in Transylvania, Romania, was analysed in order to determine the differences between them. VOCs collected using solid phase microextraction (SPME) technique were analysed by gas-chromatography coupled with mass-spectrometry (GC-MS). The fiber used was Carboxen / PDMS (polydimethylsiloxane) 75�m. By qualitative analysis, a number of 98 volatiles in unifloral honey and 52 volatiles in multifloral honey were identified. The differences regarding volatile compounds of multifloral honey were observed to be between varieties from different areas of Transylvania (mountain, plain, hill and urban area) while in the case of unifloral assortments (rapeseed, acacia, sunflower and linden) differences were observed at specific compounds. Compounds identified in our samples were grouped into main classes of substances: hydrocarbons, alcohols, aldehydes, ketones, organic acids and their esters, furan and pyran derivatives and terpenes.

Comparison of Physicochemical, Microbiological Properties and Bioactive Compounds Content of Grassland Honey and other Floral Origin Honeys

The aim of this study was to compare the physicochemical, the microbiological, and the antioxidant characteristics of unifloral honey, polyfloral honey, honeydew, and hay meadows honey. Hay meadow is type of semi-natural grassland with a great floral diversity, an important resource for pollinators. Grasslands are the source of the spring nectar honey obtained in May and June. Water content, sugars (fructose, glucose, sucrose, trehalose, melezitose, maltose, erlose, turanose, and raffinose), electrical conductivity, phenolic content (gallic acid, protocatechuic acid, 4-hydrxybenzoic acid, vanilic acid, chlorogenic acid, caffeic acid, p-coumaric acid, rosmarinic acid, myricetin, quercitin, luteolin, kaempferol), color, viscosity, and microbiological characteristics were performed for all samples of honey. The total polyphenols content was significant for grassland honey (21.50 mg/100 g) and honeydew (30.49 mg/100 g) and less significant for acacia (0.08 mg/100 g) and rape honey (0.14 mg/100 g). All samples were microbiologically safe, and standard plate count (SPC) values were <10 cfu/g for all the samples, but the grassland honey had the highest microbiological quality: 33.3% of samples without microorganisms, 50.0% with the presence of yeast under limit, and 16.7% with yeast and mold under limit, a situation that does not meet other types of honey. The results of statistical analysis obtained with principal component analysis (PCA) showed a major difference between the grassland honey and the other types of honey.

Contribution to the Chromatic Characterization of Unifloral Honeys from Galicia (NW Spain)

Honey color and other physicochemical characteristics depend mainly on the botanical and geographical origin. The study of these properties could make easier a correct classification of unifloral honey. This work determined the palynological characteristics and some physicochemical properties such as pH, electrical conductivity, and color (Pfund scale and the CIELa*b* coordinates), as well as the total content of the bioactive compounds phenols and flavonoids of ninety-three honey samples. Samples were classified as chestnut, blackberry, heather, eucalyptus, and honeydew honey. The study showed a close relationship between the physicochemical variables and the botanical origin. The five types of honey presented different physicochemical properties among them. A principal component analysis showed that Hue, lightness, b*, and Chroma variables were important for the honey types classification, followed by Erica pollen, pH, Cytisus, and Castanea variables. A forward stepwise regression analysis was performed introducing as dependent variables the color (mm Pfund) and the Chroma and the Hue variables. The regression models obtained explained 86%, 74%, and 86% of the variance of the data, respectively. The combination of the chromatic and physicochemical and pollen variables through the use of multivariable methods was optimal to characterize and group the honey samples studied.