Effect of inverted saccharose on some properties of honey

In this study, three groups of honey [natural honey; honey produced by the supplementary feeding of bees with saccharose syrup (SSH) and heat and acid (88 °C, 2 h; 0.1% HCl) treated saccharose syrup honey (ISSH)] were produced and physicochemical (water content, pH, free acidity, ash, HMF, diastase activity, sucrose, protein and viscosity), microbiological and sensory properties of these honeys were determined. Also, mineral contents of the honeys were measured. Moisture and ash contents of SSH were higher, acidity level was lower than those of other honeys. The mineral content of natural honey was higher than that of the others, except for Pb and Zn. Diastase activity of ISSH was below the standard limit and HMF content of this honey was high, but not exceeding the limit. Supplementary feeding of honey bees with inverted (acid and heat treatment) saccharose yielded a honey which had a higher HMF content and a lower diastase activity, moisture content and free acidity than natural honey or SSH.     

Major flavonoids of Argentinean honeys. Optimisation of the extraction method and analysis of their content in relationship to the geographical source of honeys

In the present research we optimised an extraction procedure for the flavonoid aglycones: myricetin, quercetin and luteolin from honeys (as natural biological matrices), based on Amberlite XAD-4 resin followed by HPLC quantification. In addition, honeys from three geographical regions of Argentina were analysed with regard to the contents of these flavonoids. The extraction procedure was optimised for XAD-4 resin considering: resin/honey ratio, elution volume to desorb flavonoids and colour intensity of honeys. Differences in flavonoid recoveries were observed depending on the colour intensity. The flavonoid aglycones contents, in accordance with differences in geochemical characteristics and typical vegetation, varied with the geographical origin of honeys. The results obtained allowed us to consider these three flavonoids as chemical markers for the phytogeographical origin of honeys. In the case of monofloral honeys, the contribution of each one of the flavonoids was associated with the presence of a dominant pollen kind in these samples.     

Differentiation of monofloral citrus,rosemary, eucalyptus,lavender, thyme and heather honeys based on volatile composition and sensory descriptive analysis

The volatile profiles of 49 Spanish honey samples of different botanical origins were obtained by means of gas chromatography–mass spectrometry and sensory analysis. Citrus honeys were characterised by higher amounts of linalool derivatives, limonyl alcohol, sinensal isomers, and α-4-dimethyl-3-cyclohexene-1-acetaldehyde, together with fresh fruit and citric aromas; eucalyptus honeys had hydroxyketones (acetoin, 5-hydroxy-2,7-dimethyl-4-octanone), p-cymene derivatives, 3-caren-2-ol and spathulenol, cheese and hay aromas; lavender honeys had hexanal, nerolidol oxide, coumarin, important concentrations of hexanol and hotrienol and sensorial attributes, including balsamic and aromatic herb aromas; finally, heather honeys were characterised by high contents of benzene and phenolic compounds and ripe fruit and spicy aromas. Some of these compounds and sensory attributes were only found in honeys from a specific floral source and could thus be of interest for use as markers of their botanical origin.     

Classification of Honey According to Geographical and Botanical Origins and Detection of Its Adulteration Using Voltammetric Electronic Tongue

Main possible honey fraud is the addition of various sugar syrups. But, there are also other types of fraud, such as deception on the geographical and/or botanical origin product. Providing a product of the hive with full authenticity is therefore crucial for the preservation of beekeeping. In this pursuit, voltammetric electronic tongue (VE-tongue) was employed to classify honey samples from different geographical and botanical origins. Furthermore, VE-tongue was used to detect adulterants such as glucose syrup (GS) and saccharose syrup (SS) in honey. The data obtained were analyzed by three-pattern recognition techniques: principal component analysis (PCA), support vector machines (SVMs), and hierarchical cluster analysis (HCA). These methods enabled the classification of 18 honeys of different geographical origins and 7 honeys of different botanical origins. Excellent results were obtained also in the detection of adulterated honey. Therefore, this simple method based on VE-tongue could be useful in the honey packaging and commercialization industry.     

Evaluation of HS-SPME and ultrasonic solvent extraction for monitoring of plant flavours added by the bees to herbhoneys: traceability biomarkers

The volatile composition of 21 herbhoneys (HHs) of 7 different botanical origins was characterised for the first time. Ultrasound solvent extraction (USE) and headspace solid-phase microextraction (HS-SPME) followed by GC-FID/MS were successfully applied as complementary methods for monitoring the volatile plant flavours added by the bees. HHs showed significant compositional variability related to the botanical origin and compounds that could serve as traceability biomarkers were identified. The most important compounds with high abundance were (E,extract; H, headspace): caffeine (up to 68.7%, E) and trans-linalool oxide (up to 26.0%, H) in coffee HH, α-terpineol (up to 8.2%, E; 27.1%, H) and bornyl acetate (up to 3.1, E; 11.9%, H) in pine HH, thymol (up to 3.1%, E; 55.4%, H) in thyme HH. Hawthorn HH was characterised by the presence of herniarin (up to 13.4%, E) and lemon HH contained limonene (up to 1.6%, E; 33.2%, H). Other HHs (nettle and aloe) contained lower amounts of volatiles and their profiles were not specific. In all the HHs, methyl syringate was found and it was most abundant in thyme HH (up to 17.4%, E). The volatile fraction of HHs showed some substantial similarities and differences with the composition of herbs from which they derive. It confirms the selective bee-mediated transfer of phytochemicals, including known flavour-active volatiles into the final product, but also biotransformation of several compounds. Additionally, several similarities to the corresponding natural honeys were observed, but in general HHs exhibited less rich volatile profiles.     

Some physico‐chemical characteristics of honeys produced from sunflower plant (Helianthus annuus L.)

This study was conducted to determine the physico‐chemical characteristics of honeys (n = 52 samples) produced from sunflower in Trakya region of Turkey. We have evaluated the conformity of the honeys in accordance with the criteria specified by the Turkish Honey Standard (TS 3036), Turkish Food Codex and European Union Commission. According to the results of our analysis, the average values determined were in Tekirdag (n = 10 samples), Malkara (n = 22 samples), Hayrabolu (n = 13 samples) and Muratl? (n = 7samples) respectively: 6.67%, 6.06, 8.43, 7.89 for hydroxymethyl furfural (HMF); 15.02, 23.98, 18.61, 17.61 (Goethe unit) for diastase activity; 2.01%, 2.39, 2.36, 1.69 for saccharose; 75.26, 73.78, 75.50, 76.80 for invert sugar (%); 23.38, 34.92, 31.70, 26.38 for meq kg^?1 for acidity; 0.16, 0.25, 0.31, 0.13 for ash value (%); 18.13, 18.21, 17.52, 18.21 for water content (%).     

Unifloral honeys of the province of Buenos Aires,Argentine

Samples of 63 unifloral honeys of the province of Buenos Aires, Argentina, from Eucalyptus spp, Lotus spp, Helianthus annuus, Melilotus albus, Brassicaceae, clovers other than Lotus and Melilotus, and Sagittaria montevidensis, were obtained by cold extraction at the laboratory. The frequencies of occurrence of pollen types, and the moisture, hydroxymethylfurfural, ash, acidity and proline contents were determined. Electrical conductivity, pH and colour were also analysed. Honey presented a high percentage (about 40%) of unifloral honey. The most frequent unifloral honeys were from Eucalyptus spp, Lotus spp and Helianthus annuus. Samples had a low pollen diversity with six to 19 pollen types, the most important nectariferous taxa being those that characterized the unifloral honeys. All samples presented moisture, hydroxymethylfurfural, ash and free acidity contents according to international standards. The colour of the honey was from water white to light amber, and all samples had a very low ash content. Significant differences at the 5% level in the hydroxymethylfurfural content, electrical conductivity, colour and proline content were observed among honeys from different floral origins. However, a high variability between samples from the same floral origin was observed, indicating that other factors such as accompanying pollen and geographical origin affect the physicochemical characteristics of honey. Copyright © 2005 Society of Chemical Industry     

HPLC flavonoid profiles as markers for the botanical origin of European unifloral honeys

The HPLC phenolic profiles of 52 selected unifloral honey samples produced in Europe were analysed to detect possible markers for the floral origin of the different honeys. Lime‐tree (five markers), chestnut (five markers), rapeseed (one marker), eucalyptus (six markers) and heather (three markers) honeys had specific markers with characteristic UV spectra. In addition, the flavanone hesperetin was confirmed as a marker for citrus honey, as well as kaempferol for rosemary honey and quercetin for sunflower honey. Abscisic acid, which had been reported to be a possible marker for heather honey, was also detected in rapeseed, lime‐tree and acacia honeys. Ellagic acid in heather honey and the hydroxycinnamates caffeic, p‐coumaric and ferulic acids in chestnut, sunflower, lavender and acacia honeys were also detected. The characteristic propolis‐derived flavonoids pinocembrin, pinobanksin and chrysin were present in most samples in variable amounts. © 2001 Society of Chemical Industry     

Aroma profile and physico‐chemical properties of artisanal honey from Tabasco,Mexico

The aim of this work was to characterise, physico‐chemically, sugar composition and aroma profile of ten honey samples collected by small producers during two seasons and produced in different agricultural ecosystems from Tabasco State (Mexico). The mean values obtained for the physico‐chemical parameters were: pH 3.63; 19.25% moisture; 78.8°Brix sugar; 0.64% ash; 0.25 mS cm^?1 electrical conductivity and 0.58 water activity. Based on colour parameters, Tabasco honeys can be placed in the group of dark honeys. In the analysed samples; fructose was the major sugar (39.45%), followed by glucose (35.74%) while sucrose only represented 2.93%. The volatile profiles of the ten honey samples were obtained by gas chromatography‐mass spectrometry. All the honeys were characterised by their high contents of benzene and furan‐related compounds. As a result, artisanal honeys from Tabasco (Mexico) can be considered to present a good level of quality.     

Vitamin C and sugar levels as simple markers for discriminating Spanish honey sources

In this work, 7 Spanish honeys with different botanical origins were studied. The honey origins were rosemary, chestnut, lavender, echium, thyme, multifloral, and honeydew. The chemical compounds determined were ascorbic acid (vitamin C), hydroxymethylfurfural, and major sugar contents (glucose and fructose). The physicochemical parameters, pH, conductivity, moisture, free acidity, and color, were also measured. Vitamin C is an important antioxidant in food, and the possibility to use it as discriminate parameter among different honeys was studied. The determination of vitamin C in honey samples was carried out by 2 different methods, volumetric and chromatographic comparing the results by both statistically. Vitamin C content was higher in thyme honeys than in the other types; however a wide dispersion in the values was found. Through a linear discriminant analysis (LDA), conductivity, glucose, fructose, and vitamin C content were the most important discriminant parameters. PRACTICAL APPLICATION: Vitamin C content in different honey sources has been determined by a simple and rapid chromatographic method (less than 3 min) in honeys from 6 botanical origins. The results together with glucose and fructose content and some physicochemical parameters have been studied in order to discriminate the botanical origin of honeys and in the future certified their quality. A statistical LDA was applied to the data, and differentiation of honey sources was possible with very good agreement. The vitamin C content found in thymus honeys was significantly higher than in other types. This fact makes vitamin C a special marker for thymus honeys that have a higher antioxidant effect than the others giving it special properties. The identification of honey sources is essential for beekeepers in order to certify honeys for consumers.     

Determination of non-volatile compounds of different botanical origin Brazilian honeys

The levels of water, HMF, free proline, total acidity, diastase activity, fructose and glucose in 74 different floral type honeys from four Brazilian regions are reported. The majority of the samples showed adequate water and HMF contents indicating the use of good practices by beekeepers in Brazil. Large variation in the contents of proline (389–520 mg/kg) was found in the honeys from the four regions studied. These findings are presumably due to the more intensive labor of the bees on the collected nectar by adding gland secretions. The high amount of diastase (40–120°G) found in some honeys from the northeast region could be due to the visit of the bees to Manhiot sp. (cassava) flour factories to collect starch-rich food, consequently increasing the diastase activity in the honey. Xerotolerant yeasts may be responsible for higher total acidity and ratios below 1 for fructose/glucose found in some samples. The majority of the analysed honeys (82%) were within the limits of the European Codex Honey Standards and Brazilian legal regulations.     

Identification of components of Brazilian honey by 1H NMR and classification of its botanical origin by chemometric methods

The potential of NMR spectroscopy to differentiate honeys concerning to the nectar employed in its production was evaluated. The application of chemometric methods to ¹H NMR spectra has allowed to discriminate the honeys produced in the state of São Paulo, being identified the signals of responsible substances for the discrimination. Application of PCA and HCA methods to ¹H NMR data have resulted in the natural clustering of the samples. Wildflower honeys were characterized by higher concentration of phenylalanine and tyrosine. Citrus honeys showed higher amounts of sucrose than other compounds, while eucalyptus honeys had higher amount of lactic acid than the others. Assa-peixe honeys showed spectra similar to eucalyptus and citrus. Sugar-cane honeys showed some signals similar to eucalyptus and citrus honeys, but also showed the tyrosine and phenylalanine signals. Adulterated honeys showed 5-hydroxymethylfurfural, citric acid and ethanol signals. KNN, SIMCA and PLS-DA methods were used to build predictive models for honey classification. In the commercial honeys prediction KNN, SIMCA and PLS-DA models correctly classified 66.7; 22.2 and 72.2% of the samples, respectively.     

Carbohydrate composition and electrical conductivity of different origin honeys from Lithuania

The main task of this study was to characterize Lithuanian honeys obtained from various sources by their carbohydrate composition and electrical conductivity and to determine if there is any dependence between these characteristics and pollen content. Twenty six samples of honey collected in Lithuania in 2006 during flowering season were analyzed by gas chromatography. Botanical source of honey samples was established by the melissopalynological method: 15 of analyzed samples were unifloral rape (winter and spring), 7 willow and 4 polyfloral honeys. Fructose, glucose, sucrose, maltose, isomaltose, turanose, trehalose, palatinose, cellobiose, raffinose and panose were identified and quantified in all samples. Glucose was predominant in 22 out of 26 samples. The mean values of fructose and glucose varied from 329.2 to 400.0 and from 346.0 to 426.3 mg/g honey, respectively. The amount of sucrose was 0.7-2.5 mg/g. Some correlations between sugar concentration and the content of pollen were established. The ratios of fructose/glucose, maltose/isomaltose, maltose/turanose, sucrose/turanose, which may be used as indicators for honey authenticity, were calculated. In addition, electrical conductivity was measured and it was found that it varied from 0.27 to 0.89 mS/cm. Unifloral rape honeys had the lowest electrical conductivity. Data obtained was thoroughly compared with previously published results and it was found that the characteristics of Lithuanian honeys in most cases meet international requirements for natural honey. However, the information on honey sugar composition and electrical conductivity was not sufficient for the reliable determination of the botanical origin of honey.     

Characterisation of Slovenian honeys on the basis of sensory and physicochemical analysis with a chemometric approach

The purpose of this study was sensory and physicochemical characterisation of Slovenian honeys with a chemometric approach. Honey samples were obtained from the beekeepers in different natural geographical macroregions of Slovenia. The sensory characteristics of the seven main types of Slovenian honeys are described, together with the physicochemical analyses. The average results of electrical conductivity (0.19–1.61 mS cm^?1), pH (4.01–5.51), free acidity (13.3–30.9 meq kg^?1), proline content (317–558 mg kg^?1), protein content (1.70–3.53 g kg^?1), optical rotation (–19.6 to 12.6), phenolic content (44.9–232.5 mg GAE kg^?1) and antioxidant activity [69.6–456.4 μm Fe(II)] show wide variability among analysed honey types. Statistically significant differences were obtained among different honey types, generally lower values of the analysed parameters were determined in the light honeys, as the acacia, linden and multifloral honeys, while the higher values are characteristic for darker honeys, as the chestnut, fir, spruce and forest honeys. Linear discriminant analysis was performed to classify the honey samples according to their botanical origin and proved that physicochemical parameters analysed can provide enough information for the classification and distinction of acacia, linden, multifloral and chestnut honeys, and the group of honeydew honeys (fir, spruce and forest honeys).     

Traces of contamination–well preserved in honey Investigation of veterinary drugs and American foulbrood in honeys of global origin

In our study, honey samples of different global and local origins were tested for antibiotic residues as well as the presence of the bacterium Paenibacillus larvae, the causative agent of the honeybee disease American foulbrood (AFB). 30 German and 47 imported non-European honeys were analyzed for sulfonamides, trimethoprim, tetracyclines, macrolides, lincomycin and chloramphenicol. 22 of the imported honeys contained residues (in most cases more than one), whereas 29 of the 30 German samples were free of residues. Sulfamethoxazole was the most frequently found antibiotic (often combined with trimethoprim). Almost all of the analyzed honeys from Argentina, China and Canada were AFB-positive (category I and II), whereas only five German honeys were AFB-positive. A correlation of present antibiotics and AFB spores was not found. For investigating putative relations between imported honeys and AFB cases in the area of Hamburg, genomic fingerprinting by PCR-amplification of repetitive DNA elements of the bacterial isolates was performed. The study shows that distinct genotypes of P. larvae are prevalent in samples of different geographical origin. AFB isolates of imported honeys differ from the predominant genotype in the area of Hamburg. Furthermore, the prevalent genotype in Hamburg was characterized by the absence of the iC9-fragment which was shown to be linked to virulence of P. larvae strains.     

Traces of contamination–well preserved in honey

In our study, honey samples of different global and local origins were tested for antibiotic residues as well as the presence of the bacterium Paenibacillus larvae, the causative agent of the honeybee disease American foulbrood (AFB). 30 German and 47 imported non-European honeys were analyzed for sulfonamides, trimethoprim, tetracyclines, macrolides, lincomycin and chloramphenicol. 22 of the imported honeys contained residues (in most cases more than one), whereas 29 of the 30 German samples were free of residues. Sulfamethoxazole was the most frequently found antibiotic (often combined with trimethoprim). Almost all of the analyzed honeys from Argentina, China and Canada were AFB-positive (category I and II), whereas only five German honeys were AFB-positive. A correlation of present antibiotics and AFB spores was not found. For investigating putative relations between imported honeys and AFB cases in the area of Hamburg, genomic fingerprinting by PCR-amplification of repetitive DNA elements of the bacterial isolates was performed. The study shows that distinct genotypes of P. larvae are prevalent in samples of different geographical origin. AFB isolates of imported honeys differ from the predominant genotype in the area of Hamburg. Furthermore, the prevalent genotype in Hamburg was characterized by the absence of the iC9-fragment which was shown to be linked to virulence of P. larvae strains.     

Multi-elemental composition and physical properties of honey samples from Malaysia

The elemental profiles of six honey samples from Malaysia had been constructed using the data obtained from both ICP-AES and ICP-MS. Potassium and sodium were the most abundant minerals covering from 69.3-78.6% and 14.1-28.7%, respectively. The ratio of potassium to sodium was more than one. Even though the minerals and trace elements composition varied dependent on the type of honey samples, there was no statistically significant difference between the analysed honey samples, namely tualang, gelam, acacia and a few forest honeys based on two-factor ANOVA and cluster analysis. The total element content of honey samples were strongly correlated with the electrical conductivity, but only have moderate correlation with the ash content and honey colour based on the regression analysis. PCA result on the available elemental data from worldwide honeys, including honey samples from Malaysia revealed that potassium and sodium were the mineral markers to distinguish honey origin. Both tualang and gelam honey samples from Malaysia have close mineral profile with sesame honeys from Egypt and multifloral honeys from India, whereas forest honeys Malaysia were near to avocado honeys from Spain and multifloral honeys from India.     

Antioxidant activity of Portuguese honey samples: Different contributions of the entire honey and phenolic extract

The antioxidant activity of Portuguese honeys was evaluated considering the different contribution of entire samples and phenolic extracts. Several chemical and biochemical assays were used to screen the antioxidant properties of entire honeys with different colour intensity and phenolic extracts: reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity, and inhibition of lipid peroxidation using the β-carotene linoleate model system and the thiobarbituric acid reactive substances (TBARS) assay. The amounts of phenols, flavonoids, ascorbic acid, β-carotene, lycopene and sugars present in the samples were also determined. The highest antioxidant contents and the lowest EC₅₀ values for antioxidant activity were obtained in the dark honey. An analysis of variance was carried out to evaluate the influence of the colour intensity and extraction method in the antioxidant properties and phenolic contents. A discriminant analysis was also performed, giving satisfactory results once the six samples were clustered in six individual groups obtained through the definition of two discriminant analysis dimensions.     

PREDICTION OF HONEY SHELF LIFE

Fourteen commercial honey samples of different botanical origin (acacia, chestnut, citrus, eucalyptus, multifloral) were stored for up to 18 months at room temperature. Both 5-hydroxymethylfurfural (HMF) and diastase were evaluated and kinetics carried out. The highest HMF increase was in citrus and eucalyptus honeys at 3 mg/kg/month; the lowest in chestnut at 0.256 mg/kg/month. The highest diastase deactivation was in eucalyptus honey at 0.485 DU/kg/month; the lowest was in chestnut at 0.258 DU/kg/month. Honey shelf life was estimated for both indices, HMF and diastase, using a Bayesian approach. The results show that commercial honey shelf life depends on botanical origin as well as processing. Except chestnut, all other honeys showed shorter shelf lives than the declared one (usually 36 months). The shortest values, 15 months, were for citrus and eucalyptus honeys. The longest, 20 months, was for acacia and multifloral honeys.

PRACTICAL APPLICATIONS

Both kinetic equations and results of simulations can be used to estimate, for quality control purposes as well as regulation requirements, the most probable value of shelf life for a specific honey.