Palynological,physico‐chemical and organoleptic characteristics of carob tree (Ceratonia siliqua L.) honey from Sicily

This study shows the results of melissopalynological and sensory evaluations on twenty‐five carob tree honey samples coming from Sicily and declared unifloral by the local beekeepers. This specific carob tree honey production is erratic and limited because of its cold weather spreading, depending on seasonal trends that influence both the final amount and quality of honey itself. According to the melissopalynological results on samples, a minimum of 15% carob tree pollen was considered sufficient to typify these honeys as unifloral. The physico‐chemical analysis was performed on the samples satisfying this percentage and determined the following parameters: moisture, pH, acidity, HMF, diastase activity, electrical conductivity, ash, sugar and colour. Physico‐chemical analyses showed medium to high values for diastase activity, electrical conductivity, free acidity and moisture.     

Pollen spectrum and physico‐chemical attributes of heather (Erica sp.) honeys of north Portugal

BACKGROUND: Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physico‐chemical properties may increase the commercial value of these products. The characteristics of 23 unifloral honeys of Erica sp., from Portugal, were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural content, apparent sucrose, reducing sugars and diastase activity) were determined. RESULTS: All honey samples can be classified as monofloral Erica sp., they gave a mean value of 56% of Erica pollen type. The families Fabaceae and Rosaceae provided the greatest number of pollen types with 8 and 4 pollen types each respectively. The second most important pollen type is Eucalyptus, present in 69.6% of the samples. All honey samples met the international physicochemical quality standards. The present study found a linear correlation (R = 0.996) between the ash content of honeys and their specific conductivity. CONCLUSION: All honey samples can be classified as monofloral Erica sp. Unifloral honeys are increasingly requested and appreciated, despite their higher prices. The samples were found to meet all major international honey specifications. Copyright © 2009 Society of Chemical Industry     

Estimation of the honeydew ratio in honey samples from their physicochemical data and from their volatile composition obtained by SPME and GC‐MS

Differentiation of nectar and honeydew honeys is difficult, not only because of the wide variability in composition and organoleptic properties among samples from the same source, but also because of the frequent existence of honeys resulting from a blend of nectar and honeydew. A mathematical expression to evaluate the relative presence of honeydew in a honey sample (HD) has been developed from relevant physicochemical properties of honey samples selected as highly representative of both honey types on the basis of their physico‐chemical and melissopalynological analysis. As honey aroma depends on its volatiles composition, GC‐MS analysis of the volatile fraction obtained by SPME has been carried out in order to evaluate its usefulness in honey source differentiation. Stepwise regression from multicomponent volatiles data was used for the estimation of HD and for determining which volatile compounds were related to the different honey sources. Copyright © 2004 Society of Chemical Industry     

Differentiation of blossom and honeydew honeys using multivariate analysis on the physicochemical parameters and sugar composition

Multivariate analysis was applied on physicochemical parameters (moisture, water activity, electric conductivity, colour, hydroxymethyl furfural, acidity, pH, proline, diastase and invertase), sugar composition (fructose, glucose, sucrose, maltose, isomaltose, trehalose, turanose and melezitose) and palinological parameters determined in blossom and suspected honeydew honeys in order to differentiate them. The majority of the physicochemical, sugar composition and palinological parameters evaluated presented significant differences in the mean values between the suspected honeydew and blossom honeys, with the exception of moisture, water activity, diastase, fructose and maltose. Blossom honey samples tend to differentiate from the suspected honeydew honeys after applying factor analysis on the physicochemical parameters and sugar composition. Stepwise linear discriminant analysis allows the correct classification of all blossom honeys, and only one honeydew honey was erroneously included as blossom honey. So, the use of multivariate analysis on physicochemical parameters and sugar composition can be a useful tool to differentiate these types of honeys.     

Characterisation of avocado (Persea americana Mill) honeys by their physicochemical characteristics

The quality of 12 avocado (Persea americana Mill) honeys from Spain was evaluated. Eight common physicochemical parameters were analysed, namely water content, pH, acidity (free, lactonic and total), sugar content, ash content and electrical conductivity. In addition, the honey samples were analysed using inductively coupled plasma optical emission spectrometry (ICP‐OES), and six minerals were quantified for each honey, namely potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), phosphorus (P) and sulphur (S). Most samples showed proper maturity considering the medium water content (mean 17.7%). The total acidity (below 50 meq kg^?1 except for one sample) indicated absence of undesirable fermentation; also, the mean pH of around 4.77 is usual in this kind of honey. The values for ash content and electrical conductivity were high (0.77% and 798 µS cm^?1 respectively) and typical of dark honeys. K was the predominant mineral (accounting for 73% of the total minerals quantified), followed by Na (10%). Copyright © 2004 Society of Chemical Industry     

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).     

Study on distribution pattern of stable carbon isotope ratio of Chinese honeys by isotope ratio mass spectrometry

The δ ¹³C values of 26 varieties of Chinese pure single‐flower honeys, 323 census samples of six varieties of single‐flower honeys and one multi‐flower honey as well as 20 888 commercial honey samples from 135 honey‐related enterprises in 25 provinces of China were analysed by stable carbon isotope ratio mass spectrometry between 1998 and 2004. It was found that the δ ¹³C values of different Chinese honeys fell within the ranges of values proposed by JW White. This shows that White's theory of the stable carbon isotope ratio of honeys is applicable to Chinese honeys and further demonstrates that the theory is universal to honeys from all over the world. The study also confirmed that the δ ¹³C values of honeys do not bear much relation to the environment in which the honey plants are grown, e.g. geographical area, water and soil, climate, etc., but do vary slightly with the honey plant species. Copyright © 2005 Society of Chemical Industry     

Comparative study of the physicochemical and palynological characteristics of honey from Melipona subnitida and Apis mellifera

Twenty‐four samples of Apis mellifera honey and twenty‐four samples of Melipona subnitida (Jandaira) honey were collected in the northeast of Brazil. Moisture, hydroxymethylfurfural, free acidity, insoluble solids in water, diastase activity, ashes, electrical conductivity, proteins, lipids, total carbohydrates, energy and sugars were the parameters analysed. The efficiency of the qualitative tests (Fiehe's test, Lugol's reaction, Lund's reaction) was tested. Pollen types and the corresponding plant species were identified in all samples (3 in Apis and 1 in Melipona). Apis mellifera honey samples demonstrated parameters in accordance with the Brazilian Legislation, while the Melipona subnitida honey samples displayed moisture (24.80%) and diastase activity (null) in discordance with the established by the regulation for Apis mellifera honeys. Apis honey samples presented higher values of electric conductivity (284.00 μS cm^?1) than the obtained from the Jandaira honey samples (102.77 μS cm^?1) as well as a darker colour (26.67 mmPfund) when compared with Jandaira honey (7.00 mmPfund). The concentration of the glucose, fructose and sucrose was higher in the Apis honeys than in the Jandaira honey. The characteristics of the two types of honey were very different, highlighting the need of developing specific legislation for stingless bees' honey.     

Palynological and physicochemical data characterisation of honeys produced in the Entre‐Douro e Minho region of Portugal

Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physicochemical properties may increase the commercial value of these products. The characteristics of thirty‐one honeys produced in the Entre‐Douro e Minho region in Portugal were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural contain, apparent sucrose, reducing sugars and diastase activity) were determined. The samples were found to meet international honey specifications. The present study found a linear regression between the ash content of honeys and their specific conductivity. Five samples are listed as Eucalyptus honey, one sample as Citrus honey, and twenty‐five samples as multifloral honeys. Of the total, 87.1% exceeded the quality parameters and should be labelled as ‘virgin’ honey.     

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.     

Characterization of monofloral honeys with multivariate analysis of their chemical profile and antioxidant activity

Abstract: Various bioactive chemical constituents were quantified for 21 honey samples obtained at Rio de Janeiro and Minas Gerais, Brazil. To evaluate their antioxidant activity, 3 different methods were used: the ferric reducing antioxidant power, the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activity, and the 2,2′‐azinobis (3‐ethylbenzothiazolin)‐6‐sulfonate (ABTS) assays. Correlations between the parameters were statistically significant (?0.6684 ≤ r ≤?0.8410, P < 0.05). Principal component analysis showed that honey samples from the same floral origins had more similar profiles, which made it possible to group the eucalyptus, morrão de candeia, and cambara honey samples in 3 distinct areas, while cluster analysis could separate the artificial honey from the floral honeys. Practical Application: This research might aid in the discrimination of honey floral origin, by using simple analytical methods in association with multivariate analysis, which could also show a great difference among floral honeys and artificial honey, indicating a possible way to help with the identification of artificial honeys.     

Floral classification of Yucatan Peninsula honeys by PCA & HS‐SPME/GC–MS of volatile compounds

In the current work, we focus on the application of principal component analysis (PCA) to differentiate the floral origin of three types of honeys of the Yucatan Peninsula, Mexico [Tahonal (Viguiera dentata Blake, var. heliantoides), Dzidzilché (Gymnopodium floribundum Rolfen) and Haabín (Piscidia piscipula L.)], by using the volatile compounds of the honey obtained by HS‐SPME/GC–MS with PDMS/DVB fibres. About 70 peaks were detected in each honey sample, many of them were found with similar retention times in the analysed honeys. The PCA with three factors (nearly 68% of the total variance) discriminates between the three types of honeys, which leads us to conclude that it is possible to successfully differentiate samples from different unifloral honeys according to their volatile composition.     

Antioxidant capacity of Spanish honeys and its correlation with polyphenol content and other physicochemical properties

Thirty‐six Spanish honeys of different floral origins (nectars and honeydews) were assessed to estimate their radical‐scavenging capacity against the stable free radical DPPH (1,1‐diphenyl‐2‐picrylhydrazyl), their ability to inhibit enzymatic browning in apple homogenate and their clarifying effect on apple juice. These capacities were evaluated spectrophotometrically. Physicochemical parameters such as pH, acidity, net absorbance, electrical conductivity and total polyphenol content of the samples were also evaluated. It was observed that all these parameters presented a strong correlation with radical‐scavenging capacity, whereas antibrowning capacity had a low correlation with conductivity and no correlation with honey pH. When data of nectar and honeydew honeys were evaluated separately, net absorbance and honey acidity seemed to be good parameters to evaluate the antioxidant activity of nectar honeys; however, in honeydew honeys there were only relationships between radical‐scavenging activity and honey conductivity and between browning inhibition of homogenates and total acidity. In general, honeydew honeys showed higher antioxidant capacities than nectar honeys. Copyright © 2007 Society of Chemical Industry     

Application of Selected Ion Flow Tube Mass Spectrometry Coupled with Chemometrics to Study the Effect of Location and Botanical Origin on Volatile Profile of Unifloral American Honeys

Abstract: Ten Ohio and Indiana honey samples from star thistle (Centaurea Americana), blueberry (Vaccinium spp.), clover (Trifolium spp.), cranberry (Vaccinium spp.), wildflower, and an unknown source were collected. The headspace of these honeys was analyzed by selected ion flow tube mass spectrometry and soft independent modeling of class analogy (SIMCA). SIMCA was utilized to statistically differentiate between honeys based on their composition. Ohio honeys from star thistle, blueberry, and clover were similar to each other in volatile composition, while Ohio wildflower honey was different. Indiana honeys from star thistle, blueberry, and wildflower were different from each other in volatile composition, while clover and cranberry honeys were similar. Honeys from Ohio and Indiana with the same floral origins were different in volatile composition. Furfural, 1‐octen‐3‐ol, butanoic, and pentanoic acids were the volatiles with the highest discriminating power between types of floral honey. Methanol and ethanol followed by acetic acid were at the highest levels in most honeys, though furfural was at the highest concentration in Indiana blueberry honey, while 1‐octen‐3‐ol was at the highest concentration in Indiana wildflower honey. The highest concentration of volatile compounds was in Indiana wildflower honey followed by Ohio wildflower honey, while the lowest concentration of volatile compounds was observed in Ohio clover honey followed by Indiana clover honey. Practical Application: Using chemometrics, concentrations of volatile compounds in different honeys can be used to determine the influence of botanical and geographical origins on aroma, which is important for the quality of honey. Characterization of volatile compounds can also be a useful tool for assessing honey quality.     

STUDIES ON LIBYAN HONEYS

Ten honey samples representing various floral types were obtained from different areas in Libya. Two other samples were obtained from hives, where bees were fed on sugar syrup and date syrup, respectively. The chemical composition and some characteristics of these samples were studied. The data obtained generally showed that the specifications of honeys produced in Libya conformed with those required for table honey. The application of thin-layer chromatography on cellulose-coated plates for the analysis of honey sugars yielded clear resolution and discrete spots. Some measures — such as high level of calcium, low level of potassium and UV-absorption spectra of honeys were suggested to be used for identifying the sugar-honeys and for ensuring the quality of blossom honeys. An attempt has been made to predict the granulation behavior of honeys and a derived regression formula was suggested.     

Phenolic profile and antioxidant properties of Polish honeys

The phenolic components of honeys have great participation in their nutritional value and antioxidant activity. Moreover, phenolic components are promising markers for the determination of botanical and geographical origin of honey. The purpose of the present work was to study the antioxidant activity and profiles of phenolic acids and flavonoids of honeys of various origins. The total phenolic content of honeys varied from 4.46 to 15.04 mg of gallic acid equivalents per 100 g of product and the total phenolic acid content determined chromatographically varied from 201.05 to 2089.08 μg per 100 g of product. Buckwheat honey exhibited the highest antioxidant activity and contained the highest total phenolic amount, whereas rape honey exhibited the lowest values in this respect. Moreover, the buckwheat honey contained the highest amount of phenolic acids. There were significant linear correlations between total phenolic content and antioxidant activity of honey extracts in the reaction with DPPH^? (1,1‐diphenyl‐2‐picrylhydrazyl) and ABTS^{? +} (2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid)) free radicals. In most samples, p‐coumaric acid was the dominant phenolic acid (39.1–677.2 μg per 100 g). The honeys also contained considerable amount of gallic acid (6.0–913.8 μg per 100 g). Among flavonoids naringenin was predominant in the most studied honey samples.     

Simplex lattice mixture design approach on the rheological behavior of glucomannan based salep-honey drink mixtures: An optimization study based on the sensory properties

The rheological properties of salep drink sweetened with different honeys were measured using a controlled-stress rheometer. Mixture design experiments were used to study the effect of interactions among pine, flower and highland honeys on the rheological properties of salep-honey drink mixture (SHDM) samples. In addition, product optimization was carried out using the ridge analysis to determine the optimum mixture proportions based on sensory properties of SHDM samples. Flower honey was the component showing the highest effect on the consistency coefficient values of SHDM samples. The preference of panelists was more prominent for the SHDM samples including the higher concentrations of highland honey with respect to odour and overall preference parameters. Optimum values of pine, flower and highland honeys in the mixture were found to be 0–85%, 0–40% and 15–100%, respectively, with respect to sensory properties. In addition, ridge analysis results revealed that the SHDM should include 65% highland honey, 35% pine honey and no flower honey to obtain the maximum overall preference score (7.24). The consistency coefficient and flow behavior index values of the sample to get maximum overall preference score (7.24) were predicted to be 3.650 Pa sⁿ and 0.435, respectively.     

Investigating the impact of botanical origin and harvesting period on carbon stable isotope ratio values (13C/12C) and different parameter analysis of Greek unifloral honeys: A chemometric approach for correct botanical discrimination

The aim of this study was to investigate the impact of botanical origin and harvesting period on carbon stable isotope ratio (¹³C/¹²C), colour intensity (CI), radical scavenging activity (%RSA), P and Sn content of Greek unifloral honeys. Thus, twenty‐four honey samples were collected during harvesting periods 2011–2012 and 2012–2013, from four different regions in Greece. ¹³C/¹²C ratios and minerals were determined using isotope ratio mass spectrometry (IRMS) and inductively coupled plasma optical–emission spectroscopy (ICP‐OES), respectively. CI and %RSA were measured using spectrophotometric assays. Results showed that only ¹³C/¹²C values and %RSA were affected by both botanical origin and harvesting period (P < 0.05). Applying then chemometric analyses to the collected data set, honeys were correctly classified according to honey type (correct classification rate 87.5% and 79.2% using the original and cross‐validation method, respectively). The use of different origin parameters has the potential to aid in honey authentication.     

Antioxidant properties and phenolic content of sulla (Hedysarum spp.) honeys from Southern Italy

The geographical origin greatly influences the qualitative and nutraceutical characteristics of honey. In this study, a total of twenty‐four sulla honeys from eight different geographical areas of Southern Italy have been examined for total phenolic content (Folin–Ciocalteu method), antioxidant activity (FRAP and DPPH assays), colour intensity (ABS₄₅₀), and identification and quantification of phenolic acids (RP‐HPLC/UV‐VIS method). The total phenolic content ranged from 47.9 (Potentino honeys) to 248.3 mg GAE per kg honey (Penisola Sorrentina honeys). The antioxidant activity ranged from 47.06% (Basso Pollino honeys) to 88.25% (Penisola Sorrentina honeys), and from 98.26 μM Fe (II) (Potentino honeys) to 786.53 μm Fe (II) (Tarantino honeys) for DPPH and FRAP assays, respectively. Major phenolic acids identified in analysed samples were gallic, caffeic and ferulic acids. Correlations between the parameters analysed were statistically significant (P < 0.05). The results of the study showed that the parameters studied are greatly affected by the peculiarities of their production area.     

Removing τ‐fluvalinate residues from press‐extracted honey

Honey is obtained from the hives of European honeybees. Honeybees can be infested by Varroa parasitism, which affects honey production. The acaricide τ‐fluvalinate used in beehives to control Varroa mites, can leave its residues in honey, pollen and wax. A monitoring study was undertaken to determine the τ‐fluvalinate residues in honey samples taken from treated hives. The τ‐fluvalinate residues were determined by gas chromatography using a short, non‐polar packed column with electron capture detection. Analysis of 50 samples showed an average residue level of 15 µg kg⁻¹. The same samples were filtered through Whatman filter paper to separate the honey from residual suspended particles. The filtered honeys showed no acaricide residues above the detection limit of 3 µg kg ⁻¹, while the average residue level determined in the sediments was 392 µg kg ⁻¹. Thus the residues of τ‐fluvalinate in honey can be eliminated by separating the honey from residual suspended particles that contain acaricide residues. Copyright © 2003 Society of Chemical Industry