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Although blossom and honeydew honeys are produced from different nectar sources, it is very difficult to distinguish them. In this study, physicochemical and biochemical properties were compared to distinguish honeydew and blossom honeys obtained from different botanical sources. The honeys of pine (Pinus spp.) and oak (Quercus, spp.) were used as honeydew honey, and chestnut (Castania sativa L.) and highland honey were used as blossom honey. Turbidity, specific optical rotation (SOR) [α]20, electrical conductivity (EC), CIEL* a*b color parameters, and moisture and pH were assessed as physical parameters. Proline, invertase activity, sugar composition, total phenolic and flavonoid contents, and antioxidant capacity were used as biochemical properties. It was determined that SOR values were the most important parameters in distinguishing honeydew and blossom honeys. Turbidity stands out as a crucial factor in differentiating between pine and oak honeys. Except for chestnut honey, electrical conductivity, CIE color Lab values, and sugar profiles were identified as additional distinguishing factors among the tested honeys. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the characteristic properties of Turkish pine honey, which is an important honeydew honey. The geographical classification of the honey was determined by applying carbon isotope, melissopalynological, and physicochemical analyses to 373 samples collected from 47 regions between 2015 and 2017 under controlled conditions. δ13C protein-δ13Choney, C4%, electrical conductivity, moisture, ash, free acidity, color CIEL* a*b attributes, optical rotation [α]20, proline, diastases activities, and sugars (fructose, glucose, sucrose, and maltose) were used as physicochemical properties. Number of honeydew elements /number of total pollen (NHE/NTP) ratios were studied at melissopalynological analyses. The results showed that all samples exhibited honeydew properties, and that all physicochemical parameters met the criteria set by regulatory standards for honeydew. However, C4% sugar and δ13C protein-δ13C honey values did not meet the regulatory criteria and exhibited quite wide standard deviations. [ABSTRACT FROM AUTHOR]

Bumblebees are opportunistic resource consumers and have been known to visit extrafloral nectaries and harvest aphid and scale honeydew. We report the first observation of bumblebees foraging psyllid honeydew in a tritrophic system in the boreal forest of Yukon Territory, Canada.In this system, a willow (Salix alaxensis) develops bizarrely enlarged petiole bases which act as nursery cavities for large numbers of psyllid immatures of Cacopsylla macleani (Homoptera: Psyllidae), with later instars dispersing over the underside of the leaf.These immatures produced abundant honeydew which was vigorously and persistently foraged by several bumblebees of multiple species (we identified Bombus vancouverensis, Bombus melanopygus and Bombus mckayi). Ants and vespid wasps were also present but in lower numbers.Salix alaxensis and Salix‐feeding psyllids are common throughout arctic and boreal regions, so honeydew production is potentially a supplementary food source for Bombus when floral nectar flows are limited due to low temperatures or drought. [ABSTRACT FROM AUTHOR]

The paper describes the determination of riboflavin and thiamine in the best-selling types of 13 raw and 8 commercial monofloral and multifloral honeys originating from Serbia. It was found that there is a difference in average riboflavin and thiamine content between raw and commercial honey, as well as between different honey floral varieties. The results showed that forest, meadow and oregano honey had a significantly higher content of both B vitamins compared to acacia, linden and lavender honey. On the other hand, a very low content of riboflavin and thiamine was found in honeydew honey. Among the commercial products, royal jelly was the richest in thiamine and riboflavin, followed by forest honey. In general, the quality of all of the commercial honey samples regarding these vitamins was lower than that of the raw domestic honeys. [ABSTRACT FROM AUTHOR]

Abstract Due to the increasing demand and interest of the consumers of bracatinga honeydew honey, it becomes important to know its characteristics in order to guarantee the quality of this dark honey. It is also necessary to investigate possible parameters that easily determine their differentiation from other honeys, thus guaranteeing their authenticity. Therefore, in the present study, the physicochemical characteristics and the reducing/scavenging proprieties of 16 bracatinga (Mimosa scabrella Bentham) honeydew honey samples and 25 blossom honey (different botanical origin) samples from Santa Catarina, Brazil, were investigated. Bracatinga honeydew honeys were defined by its high free acidity, electrical conductivity and reducing/scavenging capacity, and low glucose content.Still, these specific parameters allowed the differentiation between bracatinga honeydew honeys and blossom honeys, from the of principal component analysis, contributing to the differentiation of these honeys. Graphical abstract Unlabelled Image Highlights • Physicochemical characteristics of bracatinga honeydew honey were evaluated. • Only six parameters were sufficient to differentiate bracatinga honeydew honey. • Bracatinga honeydew honey seems to present high acidity as a characteristic. [ABSTRACT FROM AUTHOR]

The emergent market for honeydew honey mostly in Europe has prompted increasing requirements by consumers and the honey industry for the characterisation of this type of honey. This work is a contribution to the limited knowledge of honeydew honeys in Spain. Botanical characterisation was performed on 59 honeydew honey samples from professional beekeepers hives distributed within Spain. The quantitative analysis reveals more than 75% of the samples belong to Maurizio Classes II and III, and that, in general, the Spanish Quercus honeydew honeys are characterised by medium high pollen grain content (Pn; mean = 285 197) and honeydew elements (HDEs; mean = 15 850). The analysis also resulted in the identification of spores of several fungal genera (Alternaria, Cladosporium, Drechslera, Geotrichum, Phithomyces, Stemhylium, Torula, Ulocladium and Venturia). All honey samples had a smaller ratio of honeydew elements to pollen grain content (mean HDE/Pn = 0.12), and for the majority of samples (93%) the ratio HDE/Pn was very low (< 0.3), suggesting that this traditional ratio value should not be considered as an indicator of honeydew honeys. The qualitative analysis of the samples showed the presence of 73 taxa belonging to 38 families. Pollen grains of Quercus f., Rubus ulmifloius f., Campanula erinus gr., Capsella f., Cytisus scoparius f., Echium plantagineum gr., Cistus ladanifer f. or Castanea sativa, and, to a lesser extent, those of Crepis f.,Eucalyptus f., Senecio f., Halimium f., Erica australis, Plantago f., Salix triandra gr. and Centaurea calcitrapa gr. are representative of Spanish oak honeydew honeys. [ABSTRACT FROM AUTHOR]

Abstract: In honeys, several molecules have been known for their antibacterial or wound healing properties. Corsican honeys just began to be tested for their antimicrobial activity with promising results on Pseudomonas aeruginosa. So, identification of active molecules and their mode of action was determined. Hydrogen peroxide concentrations were evaluated and, in parallel, the minimal inhibitory concentrations (MIC) values were performed with and without catalase. More, the quantity of phenolic compounds and ORAC assay were measured. Observation of antibacterial action was done using scanning electron microscopy (SEM) followed by plasmidic DNA extraction. MIC values of chestnut grove and honeydew maquis honeys vary between 7 and 8%, showing a strong antimicrobial capacity, associated with a plasmidic DNA degradation. When catalase is added, MIC values significatively increase (25%) without damaging DNA, proving the importance of H2O2. This hypothesis is confirmed by SEM micrographies which did not show any morphological damages but a depletion in bacterial population. Although, such low concentrations of H2O2 (between 23 μmol l−1 and 54 μmol l−1) cannot explain antimicrobial activity and might be correlated with phenolic compounds concentration. Thus, Corsican honeys seem to induce DNA damage when H2O2 and phenolic compounds act in synergy by a putative pro‐oxidant effect. Significance and Impact of the Study:: We started to determine the antibacterial efficiency of Corsican chestnut grove and honeydew maquis honeys on Pseudomonas aeruginosa. No morphological alteration of the bacterial surface was observed. Antimicrobial action seems to be related to the synergy between hydrogen peroxide and phenolic compounds. The exerted pro‐oxidant activity leads to a degradation of P. aeruginosa plasmidic DNA. This is the first study that investigate the primary antibacterial mechanism of Corsican honeys. [ABSTRACT FROM AUTHOR]

BACKGROUND Due to the increasing valuation and appreciation of honeydew honey in many European countries and also to existing contamination among different types of honeys, authentication is an important aspect of quality control with regard to guaranteeing the origin in terms of source (honeydew or floral) and needs to be determined. Furthermore, proteins are minor components of the honey, despite the importance of their physiological effects, and can differ according to the source of the honey. In this context, the aims of this study were to carry out protein extraction from honeydew and floral honeys and to discriminate these honeys from the same botanical species, Mimosa scabrella Bentham, through proteome comparison using two-dimensional gel electrophoresis and principal component analysis. RESULTS The results showed that the proteome profile and principal component analysis can be a useful tool for discrimination between these types of honey using matched proteins (45 matched spots). Also, the proteome profile showed 160 protein spots in honeydew honey and 84 spots in the floral honey. CONCLUSION The protein profile can be a differential characteristic of this type of honey, in view of the importance of proteins as bioactive compounds in honey. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Honey is a product traditionally consumed due to its possible health benefits promoted by natural antioxidants. However, few studies have evaluated the effect of in vitro gastrointestinal digestion on these compounds in honeys. To improve the knowledge of this subject, the present study aimed to investigate the influence of simulated digestion on the stability of antioxidant capacity (FRAP, DPPH, and Folin-Ciocalteu assays), phenolic compounds (LC-ESI-MS/MS), and minerals (CE-DAD) in Mimosa scabrella Bentham honeydew honeys. The results show that the digestive system, mainly after duodenal digestion, significantly decreased the antioxidant capacity assessed by FRAP (410.3 ± 18.3 to 564.7 ± 8.4 μmol Fe + 2 100 g − 1 ), DPPH (30.1 ± 0.8 to 33.9 ± 1.4 mg AAE 100 g − 1 ), and Folin-Ciocalteu assays (58.3 ± 2.6 to 142.0 ± 1.6 mg GAE 100 g − 1 ) of this honey. However, phenolic compounds and minerals showed high stability and in some cases, significantly increased after the simulated digestion, presenting a bioaccessible fraction that ranged from 78.2 ± 6.4 to 174.38 ± 6.82% and 94.0 ± 4.3 to 220.5 ± 3.4%, respectively. Therefore, these honey constituents may be considered highly bioaccessible and potentially bioavailable. Additionally, the correlation between the investigated parameters suggests that other honey constituents could also possibly affect antioxidant capacity of this honey. In conclusion, the bracatinga ( Mimosa scabrella Benth.) honeydew honey can be highlighted as an important natural source of bioaccessible polyphenols, besides presenting highly bioaccessible minerals in its composition, maintaining a satisfactory antioxidant capacity. [ABSTRACT FROM AUTHOR]

This research intends to reveal the effects of different storage temperatures on the HMF amounts and diastase activities of strained flower honey and honeydew honey samples produced by different companies in Turkey. In this context, the initial HMF values and diastase activities of the strained flower honey and honeydew honey samples belonging to five different companies, collected at the date of filling, were examined with defined quality criteria (moisture, sugar, pH, acidity, electrical conductivity and ash). Samples were stored at certain temperatures (10±2 °C, 22±2 °C, 35±2 °C), and were analyzed at the end of each of the threemonth periods (3rd, 6th, 9th and 12th months) regarding HMF and diastase activity. According to the results, average HMF values of the flower honey and honeydew honey samples stored at 10±2 °C and 22±2 °C for one year did not exceed 40 mg/kg, which is given as the limit HMF value in the Turkish Food Codex (TFC) Directive on honey, while it rapidly increased in the samples stored at 35±2 °C, and was determined to be over 40 mg/kg as of 6th month onwards. In addition, average diastase activities of the samples at 10±2 °C and 22±2 °C did not drop below the limit value of 8 in TFC, though it was determined to be below 8 as of 6th month onwards, for the flower honey stored at 35±2 °C. To conclude, decrease in diastase activity shortens the shelf lives set by the firms. By providing proper production and storage conditions, all quality criteria should be ensured to remain consistent with the TFC Directive on honey. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the usefulness of the e-tongue and physico-chemical analyses (pH, electrical conductivity (EC), colour parameters (L*, a*, b*, chroma and hue angle)) for honeydew honey adulteration detection. For this purpose the honeydew honeys have been adulterated with inverted sugar and malt wort in different percentages (5, 10%, 20%, 30%, 40% and 50% respectively). The e-tongue used consisted of three electrodes: the reference electrode (Ag/AgCl), counter electrode (Glassy Carbon Electrode Rod - GC) and working electrodes (Ag and Au). The measurement has been made using the cyclic voltammetry. The addition of malt wort and inverted sugar influenced all the physico-chemical and e-tongue parameters. The addition of malt wort decreased the magnitude of the colour parameters (L*, a* and b*) and pH, and increased free acidity and electrical conductivity. The addition of inverted sugar increased the colour parameters' values and free acidity and decreased the electrical conductivity and pH. According to the principal component analysis (PCA) the samples with 5% and 10% inverted sugar and 5% malt wort are placed near to the authentic samples, so we can conclude that the samples have physico-chemical and etongue parameters closed to the authentic honeydew honey. [ABSTRACT FROM AUTHOR]

Honey bees, Apis species, obtain carbohydrates from nectar and honeydew. These resources are ripened into honey in wax cells that are capped for long-term storage. These stores are used to overcome dearth periods when foraging is not possible. Despite the economic and ecological importance of honey, little is known about the processes of its production by workers. Here, we monitored the usage of storage cells and the ripening process of honey in free-flying A. mellifera colonies. We provided the colonies with solutions of different sugar concentrations to reflect the natural influx of nectar with varying quality. Since the amount of carbohydrates in a solution affects its density, we used computer tomography to measure the sugar concentration of cell content over time. The data show the occurrence of two cohorts of cells with different provisioning and ripening dynamics. The relocation of the content of many cells before final storage was part of the ripening process, because sugar concentration of the content removed was lower than that of content deposited. The results confirm the mixing of solutions of different concentrations in cells and show that honey is an inhomogeneous matrix. The last stage of ripening occurred when cell capping had already started, indicating a race against water absorption. The storage and ripening processes as well as resource use were context dependent because their dynamics changed with sugar concentration of the food. Our results support hypotheses regarding honey production proposed in earlier studies and provide new insights into the mechanisms involved. [ABSTRACT FROM AUTHOR]

In honey, the content of proteins, including the enzymes, is relatively low and has a minor nutritive significance. On the other hand, the proteins, including the enzymes, are usually used as honey quality evaluation parameters. This is because protein content and enzyme activities vary regarding the botanical origin of the honey. Since the results of protein content, glucose-oxidase, and acid phosphatase, for honeys produced in Croatia, are not available, four of the most abundant honey types produced in Croatia (black locust, sage, chestnut, and honeydew honey) are characterised according to the protein and proline content and enzyme activities. The characterisation was done to determine specificities and contribute to the characterisation of unifloral honeys. Dark honey types (honeydew and chestnut honey) had a higher proline content, and diastase, invertase, and glucose-oxidase activity than lighter sage and black locust honey. Black locust honey has a naturally low enzyme activity and showed the highest acid phosphatase activity among the analysed honey types, while honeydew honey, otherwise known to possess high proline content and enzyme activity, had a low protein content comparable to black locust honey. Statistically significant correlations were obtained between all analysed parameters, with the exception of acid phosphatase activity. [ABSTRACT FROM AUTHOR]

Our aim is the characterization of Anatolian monofloral and honeydew honeys according to their mineral, vitamin B2, total phenolic contents and antioxidant activities. Five main elements (Ca, K, Fe, Cu, and Mn) were determined in 20 honey samples by inductively coupled plasma – optical emission spectrometry (ICP-OES). The vitamin B2 contents of honey samples were determined by the capillary electrophoresis method coupled with a sensitive laser induced fluorescence (LIF) detector. The total phenolic contents were analyzed with Folin–Ciocalteu's method. Two comparative antioxidant assays, namely cupric reducing antioxidant capacity assay (CUPRAC) and ABTS radical scavenging assay, were applied to detect the antioxidant power of honeys. Heather honeys were distinguished from others with significantly high vitamin B2 and iron contents. Considerably higher antioxidant capacities and Mn contents were observed for oak and chestnut honeys. Principal components analysis was applied to the analysis result in order to classify the honeys from different botanical origins. [ABSTRACT FROM AUTHOR]

This study investigated some physico-chemical and biochemical characteristics of different honey types belonging to Turkish flora. Sixty-two honey samples were examined on the basis of pollen analyses, including 11 unifloral honeys (chestnut, heather, chaste tree, rhododendron, common eryngo, lavender, Jerusalem tea, astragalus, clover and acacia), two different honeydew honeys (lime and oak), and 7 different multifloral honeys. Electrical conductivity, moisture, Hunter color values, HMF, proline, diastase number, and sugar analyses of the honey samples were assessed for chemical characterization. Some phenolic components were analyzed by reverse phase high performance liquid chromatography (RP-HPLC) to determine honeys’ phenolic profiles. Total phenolic compounds, total flavonoids, ferric reducing antioxidant capacity (FRAP) and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity were measured as antioxidant determinants. The study results confirm that physico-chemical and biological characteristics of honeys are closely related to their floral sources, and that dark-colored honeys such as oak, chestnut and heather, have a high therapeutic potential. [ABSTRACT FROM AUTHOR]

In purpose to examine the antioxidant activity of 15 natural honeys of different origin ABTS method was used, total phenol content and dry matter content of honey samples were determined. Honeys were collected from different locations of Slovakia, Poland and Serbia and were represented as monofloral and multifloral samples (10) which originated from Poland and Slovakia, forest samples (4) originated from Serbia and honeydew honey. Average values of antioxidant activity observed in samples of honeys ranged from 0.62 to 4.63 mmol/kg. The highest antioxidant activity was detected in buckwheat honey and the lowest was shown in acacia honey. By observing the impact of individual honey samples on antioxidant activity it was found that the sample had a highly statistically significant effect. 10 homogeneous groups which varied in the antioxidant activity among each other were established by all 15 samples. Antioxidant activity of honeys could be a positive influence factor in terms of honey differentiation, especially in the case of the forest honeys collected from different places. Monofloral and multifloral honeys (10) established 5 homogenous groups, but in the case of several multifloral honeys which originated from different places of Poland and Slovakia no statistically significant differences were found. [ABSTRACT FROM AUTHOR]

The present study was undertaken to determine the physico-chemical properties (moisture content, reducing sugars, proline content, electrical conductivity, ash content, pH, titrable acidity, HMF, water activity, total soluble solids and total solids), enzymatic activity (diastase and invertase), colour characteristics (mmpfund, ABS450 and CIE L*a* b*) and mineral content (Cu, Mn, Fe, Zn, Pb and Cd) of three different varieties of honeys from Kashmir valley of India (acacia honey, pine honeydew and multifloral honey). Of the honey samples analysed, only pine honeydew were grouped in dark category of honey (L*<50) while acacia honey and multifloral honey were confirmed as light coloured honeys (L*>50) and possessed both red and yellow components. The concentrations of mineral content were found highest in pine honeydew followed by multi floral and least in acacia honey. All the physico-chemical properties and enzymatic activity indicated that all the three analysed varieties of honey met the criteria set by the International Honey Commission and revised codex standards for honey. The source of honey had a significant effect (p<0.05) on physico-chemical characteristics, enzymatic activity, mineral content and colour properties. Strong and positive correlations exhibited among minerals, colour (mmpfund) and L* value indicated that dark coloured honey contained high mineral content. Multivariate analysis proved to be an effective tool in classifying the three varieties of honey based on physico-chemical characteristics, enzymatic activity, mineral content and colour properties. [ABSTRACT FROM AUTHOR]

Pollen was analysed in 30 unifloralEuphorbiahoney samples from the Ifni Massif Region (Anti Atlas, Morocco). The honey samples were directly provided by beekeepers. The quantitative analyis showed that nectar is the main honey source in the samples studied. The qualitative analysis of the samples showed the presence of 35 taxa belonging to 17 families. The MoroccanEuphorbiahoneys of the studied region are characterized by their low–medium number of pollen grains (NGP; mean = 5700), 76% of the honeys belong to Class I and II of Maurizio, and by their low honeydew indicator (HDE/NGPn < 0.28), wich indicates their floral origin. For theEuphorbia officinarumsubsp.echinushoneys, the most characteristic accompanying species areEryngium ilicifolium, present in > 90% of the samples, followed byBellissp.,Capsellaf. andResedasp. (85%). However, for theE. regis-jubaehoneys, the most characteristic accompanying species areCrepisf., present in 100% of the samples. [ABSTRACT FROM AUTHOR]

As several analytical methods have to be used together for a reliable authentication of the botanical origin of honey, such work is time consuming and costly. Thus, there is a real need for new methods that allow a rapid and reproducible authentication of the botanical origin of honey at low cost. Compared to spectroscopic techniques based on absorption, fluorescence spectroscopy offers a 100-1000-fold higher sensitivity and it was used to investigate authentication of the botanical origin of honey. Excitation spectra of acacia, meadow and honeydew honeys were scanned from 220 to 400 nm with the emission measured at 420 nm. All honey types showed significant fluorescence maxima of intensity between 220 nm and 257 nm. Samples of meadow honey had higher intensity of fluorescence when compared to acacia honey (3-fold), while honeydew honey showed different intensities of fluorescence. Acacia honey exhibits second maximum between 325 nm and 385 nm while honeydew and meadow honeys did not show significant fluorescence intensity in this range. Emission spectra at 420 nm with an excitation from 220 to 400 nm on Spectrofluorimeter may be used for the identification of acacia honey. [ABSTRACT FROM AUTHOR]

The objective of the present study is to examine samples of bee honey of different origin and create models for their classification through spectral analysis in the nearinfrared spectrum. Representative samples unifloral (sunflower, acacia, lime and coriander), multifloral and honeydew honey are used. The origin of the above honey samples has been determined in advance by pollen analysis. The spectral measurement (NIR spectroscopy) of each sample was done non-destructively, by measuring the diffuse reflection of the honey samples using the spectral device NIRQuest512 within the range 900-1700 nm. The spectral differences between the different types of bee honey have been studied. For classification of the samples based on their spectra the SIMCA method (Soft Independent Modeling of Class Analogy) was used. Models for distinguishing different types of bee honey- unifloral, multifloral and honeydew - have been obtained. The results show 100% accuracy of classification of the samples from the three groups based on the received spectral information. The most compact is the group of honeydew honey. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinase-9 (MMP-9) appears to be a major protease responsible for the degradation of matrix and growth-promoting agents in chronic wounds. Honey has been successfully used for treating non-healing wounds associated with infections. However, the mechanisms of its action at the cellular level have remained poorly understood. The aim of this study was to investigate the effect of fir honeydew honey on TNF-α-induced MMP-9 expression and secretion from human keratinocytes (HaCaT) and to identify the honey component(s) responsible for a discovered effect. A C18 solid-phase column was used for preparation of honey aqueous extract (HAE). Expression and production of MMP-9 by HaCaT cells were determined by reverse transcription-PCR, gelatine zymography and Western blot analysis using a polyclonal antibody against MMP-9. We found that HAE inhibited TNF-α-induced production of MMP-9 in keratinocytes in a dose-dependent manner at both the mRNA and protein levels. Apigenin and kaempferol, identified flavonoids in HAE, markedly inhibited MMP-9 production from HaCaT and epidermal keratinocytes. Taken together, fir honeydew honey, which contains certain flavonoids, prevents TNF-α-induced proteolytic activity in cutaneous inflammation. Thus, our findings provide clear evidence that honey may serve as a natural treatment for dermatological problems associated with a persistent inflammation. [ABSTRACT FROM AUTHOR]

The objectives of the study on the perceptions of different honey varieties produced in Transylvania originate in the assumption that in the region under study there is a great diversity of honey varieties, but there are not significantly promoted so that they are known and purchased by consumers. The research was conducted using the sociological survey and a number of 1449 questionnaires was applied, both in urban and rural areas. The results show that the most popular honey among consumers in the North West Region is the acacia honey, followed by polyfloral honey and linden honey. The least purchased varieties (and hence less consumed) are honeydew and calluna vulgaris honey. A deeper analysis of the most purchased types of honey leads to the following conclusion: honey is bought by persons with higher education or by those with high occupational status, and also by the median age category (26-50 years old). The quantitative results of the study were completed by a sensory analysis based on the use of the certain varieties of honey (acacia, linden, sunflower, honeydew and mountain flowers). The results show that the more rare varieties (honeydew and mountain flowers) are actually very pleasant for consumers, but are little known. [ABSTRACT FROM AUTHOR]

The aim of study was to characterize 52 samples of Slovak honeys of six types (multifloral, acacia, rape, honeydew, forest and mixed). Physico-chemical analysis of honey included the water content, free acidity, pH, water activity, electrical conductivity, and hydroxymethylfurfural (HMF) content. In addition, the colour of honeys was measured using spectrophotometer and Commission Internationale de I'Eclairage method (CIE L*a*b*); four types of honey were used for identification: multifloral, acacia, rape, and honeydew. Mean values of physico-chemical indicators were as follows: water content 16-21%, acidity 6-42 mekv⋅kg-1;, pH 3.68-5.15, water activity 0.505-0.667, electrical conductivity 0.155-1.585 mS⋅ cm-1 and HMF content 0.17-78.5 mg⋅kg-1;. The highest HMF content was found in forest honey with one sample above the limit established by Council Directive 2001/110/EC. The colour of Slovak honeys analysed in this study was very variable and ranged from pale yellow to dark brown. Differences of physico-chemical indicators and colour of honey samples were found to be significant (P < 0.05). The CIE L*a*b* methods can be used for identification of selected honey samples. This is the first similar study on Slovak honey. [ABSTRACT FROM AUTHOR]

Abstract: In this study the mineral content of 140 honey samples, which represent three different types of honey, namely: honeydew, buckwheat and rape honey from 16 areas of Poland, were evaluated. The method is described for determination of 15 elements (Al, B, Ba, Ca, Cd, Cr, Cu, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn) in honey from Poland using ICP-MS. The data were subjected to chemometric assessment to understand the association between the elements and classify honey samples. Mainly supervised pattern recognition techniques, such as LDA and C&RT were performed for the whole data set in order to discriminate and classify honey samples according to their origin and detect corresponding markers. Analyzes revealed an excellent separation between honey samples according to their type with the efficiency of LDA model as 100%. On the other hand, a variable classification for rape, buckwheat and honeydew honeys in regards to their geographical origin could be achieved. [Copyright &y& Elsevier]

The quantity and chemical composition of honeydew produced by scale insects may influence wider community structure, but little is known about the detailed chemical composition of the honeydew found in forest ecosystems. We used gas chromatography-mass spectrometry to examine the amino acid and carbohydrate composition of honeydew from three New Zealand communities. Low molecular weight carbohydrates (mono-, di-, and tri-saccharides) were derivatized using a modified trimethylsilyl (TMS) method, and amino and non-amino organic acids were derivatized using methylchloroformate (MCF). These recently developed derivatization methods allowed us to detect atypical compounds such as sugar alcohols, fatty acids, and non-amino organic acids, in addition to the more routinely studied compounds such as sugars and amino acids. Some compounds could not be identified and may be novel. Multivariate analysis showed that honeydew from each scale insect species had a distinctive amino acid and carbohydrate signature. We suggest these chemical signatures may influence the types of consumers that are attracted to different honeydews and may explain the characteristic communities associated with these honeydews. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a commercial electronic tongue (αAstree, Alpha M.O.S.) was applied for botanical classification and physicochemical characterization of honey samples. The electronic tongue was comprised of seven potentiometric sensors coupled with an Ag/AgCl reference electrode. Botanical classification was performed by PCA, CCA and ANN modeling on 12 samples of acacia, chestnut and honeydew honey. The physicochemical characterization of honey was obtained by ANN modeling and the parameters included were electrical conductivity, acidity, water content, invert sugar and total sugar. The initial reference values for the physicochemical parameters observed were determined by traditional methods. Botanical classification of honey samples obtained by ANN was 100% accurate while the highest correlation between observed and predicted values was obtained for electrical conductivity (0.999), followed by acidity (0.997), water content (0.994), invert sugar content (0.988) and total sugar content (0.979). All developed ANN models for rapid honey characterization and botanical classification performed excellently showing the potential of the electronic tongue as a tool in rapid honey analysis and characterization. The advantage of using such a technique is a simple sample preparation procedure, there are no chemicals involved and there are no additional costs except the initial measurements required for ANN model development. [Copyright &y& Elsevier]

Abstract: In the present work we report on the compounds characteristic of larval food (royal jelly, RJ) of the honeybee (Apis mellifera L.) that were identified in 34 different samples of genuine honey and in 3 sugar-adulterated “herbal honeys” by using solid-phase extraction and gas chromatography–mass spectrometry (SPE/GC–MS). The unique feature of RJ is a set of C8, C10 and C12 hydroxy fatty acids. In all, ten acids characteristic of this bee product were identified in different combinations in the analysed honey samples, namely: 7- and 8-hydroxyoctanoic, 3-hydroxydecanoic, 9-hydroxydecanoic, 9-hydroxy-2-decenoic, 10-hydroxydecanoic, 10-hydroxy-2-decenoic (10-HDA), 3,10-dihydroxydecanoic, 2-octene-1,8-dioic and 2-decene-1,10-dioic acids. The higher relative abundance of these compounds was determined in genuine honeydew and heather honeys, and in “herbal honeys” (23.8–40.8, 18.2–48.5, and 27.0–48.4μg/g, respectively). Since RJ is known to have strong antibiotic efficacy, our results suggest that a part of the non-peroxide antibacterial activity of honey might be of bee origin. [ABSTRACT FROM AUTHOR]

From 10 administrative districts (Centre, Milas, Ortaca, Köyceğiz, Marmaris, Fethiye, Yatağan, Bodrum, Via and Datça) of Muğla province to the west of Turkey 73 honey samples were collected in October and November in the period of 2004 - 2006. Collected honey samples were analyzed under light microscope in terms of the number of honeydew elements (HDE), total pollen numbers (TPN) and electrical conductivity. For 73 honey samples, electrical conductivity and HDE/TPN ratios were examined through the Fisher's exact test to find out whether there was any parallel relationship between the two criteria. Looking at the electrical conductivity values of 50 samples identified as highly dense-superior quality pine honey in terms of HDE/TPN, it was found that all the samples had the value ≥ 0.8 mS/cm; that 8 out of 14 low density floral honey samples satisfied the criterion ≤ 0.8 mS/cm for floral honey and that 7 medium density pine + floral honey samples did not satisfy the criterion ≤ 0.8 mS/cm. Finally 2 samples of dense pine honey had a valued ≥ 0.8 mS/cm and hence satisfied the criterion. Eventually differences were found in electrical conductivity and microscopic analysis methods that distinguish pine honey from floral honey. Thus, in identifying the origin of a honeydew honey, it was statistically established that using both methods would yield more reliable results instead of engaging to a single method. [ABSTRACT FROM AUTHOR]

Toxic honey is produced in New Zealand when honey bees (Apis mellifera) forage on honeydew containing the phytotoxin tutin that is produced by the passion vine hopper (Scolypopa australis) when feeding on the poisonous plant tutu (Coriaria arborea). Observational studies suggest that there are a set of conditions required for the production of toxic honey, but these factors have not been well studied. This research aims to investigate the importance of altitude and weather conditions for the production of toxic honey in New Zealand and makes some recommendations for a review of the New Zealand Food Safety Authority (NZFSA) Food (tutin in honey) Standard 2008 that was introduced after a toxic honey outbreak in 2008. Transects were established in parts of the North Island during the summer of 2009 and were visited weekly for 6 consecutive weeks. Variables recorded were elevation, S. australis density, honeydew abundance, honey bee and wasp (Vespula spp.) presence and temperature and rainfall data. Weather conditions present during the 2008 outbreak were compared with those from 1999 to 2009. S. australis were not present at altitudes of 375 m and above; with more research, some higher areas of New Zealand may be able to be reclassified as 'low risk'. Honeydew was available in a wide range of temperature and rainfall conditions. Rainfall appeared to wash honeydew from tutu bushes; however, it quickly reappeared in densely populated sites. Honey bee and wasp presence was positively affected by the presence of honeydew, nevertheless 30-50% of the time they were observed foraging in the absence of honeydew, indicating they may feed on small amounts of dew. As the absence of honeydew is an option given by the NZFSA to demonstrate honey safety, this requires investigation. Weather conditions leading up to the 2008 toxic honey outbreak were warm and dry but were not significantly different from other years. Therefore, inadequate management practices, rather than more favourable environmental conditions were probably responsible for the 2008 toxic honey outbreak. Future research should focus on determining the conditions required for toxic levels of honeydew to be incorporated into hives, and regions that have not produced toxic honey historically should be closely studied to determine whether any fit the low-risk criteria. [ABSTRACT FROM AUTHOR]

Abstract: In our study the mineral content of 55 honey samples, which represented three different types of honey: honeydew, buckwheat and rape honey from different areas in Poland, was evaluated. Determination of 13 elements (Al, B, Ba, Ca, Cd, Cu, K, Mg, Mn, Na, Ni, Pb, Zn) was performed using inductively coupled plasma-mass spectrometry. We tried to prove that the analysis of quality and quantity of honey elements could be used to define honey origin by using ICP-MS as a technique for simultaneous determination of elements. Chemometric methods, such as CA and PCA, were applied to classify honey according to mineral content. CA showed three clusters corresponding to the three botanical origins of honey. PCA permitted the reduction of 13 variables to four principal components explaining 77.19% of the total variance. The first most important principal component was strongly associated with the value of K, Al, Ni and Cd. This study revealed that CA and PCA analysis appear useful tools for differentiation of honey samples authenticity using the profile of mineral content and they highlighted the relationship between the elements distribution and honey type. [Copyright &y& Elsevier]

Abstract: Purge and Trap (P&T) has been evaluated as a fractionation technique for the GC–MS analysis of the most volatile compounds in honey. The volatile fraction of twenty-two commercial honeys of eight different botanical sources (eucalyptus, thyme, citrus, rosemary, heather, lavender, multiflower and honeydew) was characterized by P&T–GC–MS. Hundred volatile compounds were characterized, 18 of them being determined for the first time in honey. Compounds detected included volatiles derived from the floral nectar or honeydew source such as terpenes, furan derivatives from honey processing and storage and other compounds whose origin could be related to microbial or environmental contamination. This method has also been validated with regard to data reproducibility; with relative data (percentage of total volatile composition) showing a better precision over quantitative results calculated using an internal standard. Application of multivariate statistical analysis to P&T–GC–MS data has shown to be very promising to classify samples according to their botanical origin. [Copyright &y& Elsevier]

Abstract: The majority of predators and parasitoids require non-prey food as part of their diet. The availability of suitable non-prey food can impact predator–prey and parasitoid–host dynamics and may be critical to the efficacy of biological pest control. A growing body of work addresses the role of floral nectar in conservation biological control programs. In comparison, we know relatively little about the role of honeydew as a sugar source for predators and parasitoids, in spite of the fact that honeydew is often the predominant sugar source in agroecosystems. Here we test the hypothesis that honeydew is a less suitable food source when compared with other sugar sources, using data from parasitoid literature. We also explore whether parasitoids of honeydew-producing insects show particular adaptations allowing them to optimize the exploitation of this suboptimal food source. A review of available literature supports the general hypothesis that honeydew is inferior to other sugar sources, although there is considerable variation in the quality of honeydew depending on the honeydew producer and its host plant. The accrued dataset is not consistent with our second hypothesis that parasitoids of honeydew-producing hosts fare better on this nutritionally inferior food source as compared with parasitoid species which exploit hosts that do not produce honeydew. Finally we review evidence on the use of honeydew by predators and parasitoids under field conditions and explore implications for biological pest control programs. [Copyright &y& Elsevier]

Abstract: The concentrations of 23 chemical elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Th, Tl, U, Zn) were determined in 51 honey samples of different botanical origin produced in Siena County (Italy). K, Ca, Na and Mg were the most abundant elements, with mean contents of 1195, 257, 96.6 and 56.7mg/kg, respectively. The Fe, Zn and Sr contents generally ranged from 1 to 5mg/kg. Except for Ba, Cu, Mn and Ni, the trace element contents were below 100μg/kg. The analytical data indicated a good level of quality of the honeys, especially with regard to the concentrations of toxic trace elements, such as As, Cd, Pb and Sb, and suggested a significant influence of the botanical origin on the element composition. Some local geological and geochemical features also seemed to affect the chemistry of the honey. [Copyright &y& Elsevier]

α-Amylase was extracted from honeydew honey and purified by CM-Toyopearl 650M and Toyopearl HW-55F column chromatographies. The molecular weight of the enzyme was estimated to be about 58 kDa by Toyopearl HW-55F gel chromatography and SDS-PAGE, respectively. The optimum pH was 4.0 and optimum temperature 50°C. Inactivation of the enzyme occured when the pH was higher than 8.0 or lower than 3.0. This enzyme activated by Ca2+ and Mn2+, but inhibited by Fe3+, Hg2+, Zn2+, and EDTA. TLC analysis also suggested that the purified enzyme was of the α-type. The relative rate of hydrolysis of the polymeric substance decreased with decreasing percentage of α-1,4-linkages and with increasing percentage of α-1,6-linkages in substrate. [ABSTRACT FROM AUTHOR]

The article presents information about the chemical composition of honey. It is stated that all honey get derived from nectar which is a liquid solution of sugars, amino and other acids, proteins, lipids, minerals, and other components. It is further stated that the composition of nectar--which depends on the plant species and the environmental conditions--has an absolute impact on the flavor and quality of the finished honey. It is stated that honey will not spoil because of its low moisture content. It is further stated that honey bees have a biology that is used in collecting nectar from plants, and collecting honeydew.

Feeding on sugar-rich foods such as nectar and honeydew is important for survival of many adult parasitoids. Especially in agricultural systems, honeydew is often the most prevalent carbohydrate source. However, relative to plant nectar, honeydew may be relatively unsuitable, as a result of an unfavourable sugar composition or the presence of secondary plant compounds. We studied survival of the aphid parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) on honeydew collected from various aphid species feeding on potato ( Solanum tuberosum L., cv. Desiree) (Solanaceae), wheat ( Triticum aestivum L., cv. Bobwhite) (Poaceae), or artificial diet, as well as the sugar composition of the different honeydews. Honeydews from the tested aphid species on potato, wheat, or artificial diet were found to be relatively suitable food sources for adult A. ervi, although not always as suitable as a 2 M sucrose solution. There were differences in honeydew sugar composition among the different aphid species on the various host plants. Multivariate statistics showed that the factor ‘aphid species’ had a significant influence on the sugar composition of the honeydew, explaining 27% of the variation in the potato system and 89% in the wheat system. When exploring the relationship between carbohydrate composition of the honeydews from aphids on potato and wheat plants, and their nutritional value for A. ervi, data revealed that differences in parasitoid longevity can to some extent be explained by carbohydrate composition. Furthermore, our results confirm that sucrose and its hexose components glucose and fructose are very suitable carbohydrate sources for hymenopteran parasitoids and show that parasitoid survival on an equimolar solution of the two monosaccharides glucose and fructose does not exceed performance on the disaccharide sucrose. [ABSTRACT FROM AUTHOR]

Based on the melissopalynology 38 honey samples collected in the central region of the Argentine province of Entre Ríos were classified by botanical and geographical origin. According to qualitative analysis, 20 honey samples were monofloral and 18 were multifloral. Dominant pollen types were Scutia buxifolia Reissek (Rhamnaceae) in six samples, Baccharis spp. (Asteraceae) in five, Lotus spp. (Fabaceae) in three, Eucalyptus spp. (Myrtaceae) and Eryngium spp. (Apiaceae) in two, Ammi visnaga (L.) Lam. (Apiaceae) and Trithrinax campestris (Burmeist.) Drude & Griseb. (Arecaceae) in one sample. One hundred and nineteen pollen types were identified belonging to 52 families; 75% of which were native species. The families best represented in number of species were Asteraceae and Fabaceae. Pollen types such as Scutia buxifolia, Trithrinax campestris, Schinus spp. (Anacardiaceae), Mimosoideae from Prosopis spp., Acacia spp., Mimosa ostenii Speg. ex Burkart, and M. strigillosa Torr. & A. Gray are considered the indicators for this geographical origin. The studied honeys were also characterized by a high frequency of Apiaceae, Brassicaceae, Astereae, Echium plantagineum L. and cultivated Papilionoideae forage species such as Melilotus albus Desr., Lotus spp. and Trifolium spp. Honeydew elements were scarce. [ABSTRACT FROM AUTHOR]

Abstract: The rheological properties of seven varieties of Polish honeys, among them five nectar varieties (acacia, buckwheat, linden, multifloral and rape), a nectar-honeydew and a honeydew variety, were investigated over a temperature range of 10–40°C. The honeys had a water content of 14.7–18.0g/100g. The viscosity curves of the samples were obtained using a rotational rheometer. All the honeys exhibited Newtonian behaviour. Their viscosity varied between 1.76 and 252.6Pas according to the kind of honey and the temperature of measurement. The temperature dependence of viscosity was described using the Arrhenius equation and the Williams–Landel–Ferry (WLF) equation. The values of flow activation energy varied between 92.34 and 105.25kJ/mol, those of glass viscosity (η G) ranged from 1.88×1011 to 2.86×1011, and the values of glass transition temperature (T G) were of 220.34–228.39K. [Copyright &y& Elsevier]

Abstract: Viscosity of honey was measured in two honeydew honeys (pine and fir) and four unifloral nectar honeys (thymus, orange, helianthus and cotton) at their initial moisture content as well as at 17%, 19% and 21% water content at 25, 30, 35, 40 and 45°C. It was found that viscosity varied between 0.421 and 23.405Pas. Shear stress varied linearly with shear rate for all the samples indicating Newtonian behaviour. Shear stress was also measured at a constant shear rate as a function of time. Viscosity was time independent. Arrhenius equation was used to express the variation of viscosity with temperature. The activation energy and the constant μ o of the Arrhenius equation were determined as a function of moisture content from regression analysis of the experimental results. Activation energy decreased linearly as the moisture content increased varying between 70.8 and 96.3kJ/mol. The constant μ o increased exponentially as the moisture content increased. [Copyright &y& Elsevier]

The first samples of recently produced fir honeydew honey, obtained from Marchalina hellenica (Gennadius) (Homoptera, coccoidea, Margarodidae), originating from Mount Helmos in Greece were analysed and examined on the basis of physical and chemical parameters including humidity, acidity, sugar profile, hydroxymethylfurfural (HMF) and diastase activity. These data were compared with five other Mediterranean honeydew honeys of different origin obtained from the literature. Analytical data of the Greek fir honey from M. hellenica honeydew complied with the E.U. legal limits. The sensorial analysis indicated that the organoleptic characteristics of this type of honeydew honey were very similar to the Greek fir honey derived from other coccids with respect to colour, taste and smell. The statistical analysis of the physico-chemical parameters of the six honey types revealed two major groups. One group consisted of three Greek honeys and the other included one Spanish and two Italian honeys. it also showed a marked similarity between the two Greek honeys that came from M. hellenica honeydew on either fir or pine trees. [ABSTRACT FROM AUTHOR]

Host feeding is the consumption of host tissue by the adult female parasitoid. We studied the function of destructive host feeding and its advantage over non-destructive feeding on host-derived honeydew in the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae). We allowed parasitoids to oviposit until they attempted to host feed. We either prevented or allowed host feeding. Parasitoids had access to sucrose solution, with or without additional access to honeydew. Parasitoids that were allowed to host feed did not have a higher egg load 20 or 48 h after host feeding than parasitoids prevented from host feeding. Host feeding did not increase the number of eggs matured within these periods, nor did the time spent host feeding positively affect any of these response variables. On the other hand, the presence of honeydew did have a positive effect on egg load 20 and 48 h after host feeding compared with parasitoids deprived of honeydew. Parasitoids with access to honeydew matured more eggs within these periods than honeydew-deprived parasitoids. Host feeding increased life expectancy, but this effect was nullified when honeydew was supplied after the host-feeding attempt. In conclusion, feeding on honeydew could be an advantageous alternative to host feeding in terms of egg quantity and longevity. This applies especially to parasitoids exploiting Homoptera, because these parasitoids can obtain honeydew from the host itself. It is possible that destructive host feeding has evolved to enable females to sustain the production of high-quality anhydropic eggs, which may be important in the parasitoid's natural environment. We argue that future studies should take natural alternative food sources into more consideration. [ABSTRACT FROM AUTHOR]

The efficacy of hydrogen peroxide treatment on the inactivation of Salmonella spp. inoculated on the external surface of cantaloupe and honeydew melon was investigated. Salmonella was inoculated onto whole cantaloupe and honeydew melon to a final concentration of 4.65 log10 CFU/cm2 and 3.13 log10 CFU/g, respectively. Inoculated whole melons stored at 5°C for up to 7 days were washed with water, 2.5% and 5% hydrogen peroxide at day 0 and 5. Hydrogen peroxide (2.5% and 5%) treatments of whole melon for 5 min caused a 3 log10 CFU/cm2 reduction of the indigenous surface microflora and a 3.0 log10 CFU/cm2 reduction in Salmonella spp. on all melon surfaces. The efficacy of the hydrogen peroxide treatments was less when the interval between inoculation and treatment of cantaloupe exceeded 24 h. Unlike cantaloupe fresh-cut pieces, Salmonella was not recovered from fresh-cut pieces prepared from treated whole honeydew melon. Growth of Salmonella occurred in cantaloupe fresh-cut pieces stored at 10 or 20 °C, and by 2 weeks, levels reached approximately 1 log CFU/g. A rapid decline in appearance and overall acceptability was observed in fresh-cut pieces prepared from untreated whole cantaloupe. While Salmonella was recovered from fresh-cut pieces from and whole treated cantaloupe, sanitizing the surface of contaminated whole melons with hydrogen peroxide before and after cutting and storage of the fresh-cut pieces at 5 °C can enhance the microbial safety and acceptability rating for about 2 weeks after processing. [Copyright &y& Elsevier]

Honey adulteration is a common practice that deceives consumers and devalues the unique curative and food properties of honey. For marketing, each honey must satisfy an internationally valid Codex standard. One of the quality parameters is diastase/amylase activity, which, if lowered, may be compensated for by the addition of foreign amylases. However, the estimation of enzyme activity does not enable identification of artificially added amylases. 45 honey samples were analyzed using label-free nanoLC-MS/MS proteomics. Four honeys were found to contain the foreign amylases from Aspergillus niger, Bacillus amyloliquefaciens and/or Bacillus licheniformis. This result was confirmed via proof of specificity at multiple levels. Furthermore, we identified a series of plant-related protein groups. Despite plant-related proteins constituting a significant portion of honey proteins, they were minor components compared to the major honey bee-derived proteins. Bioinformatic analysis also provided evidence for aphid and catalase proteins in honey, but the limited specificity of the MS/MS identified peptides must be considered. Overall, we demonstrate a proteomics approach employing LC-MS/MS that is useful for proving adulteration and assessing honey quality. As an resource useful for reference, we provide curated sequence databases. In addition, we provide many markers that are naturally found in honey for future studies. Honey is unique natural product used since ancient times as a food and natural medicine. Humans strive to understand honey components because they can characterize different types of honey and be used for authentication and origin assessment. One of the important honey components are proteins. The proteins present in honey can naturally occur in honey, but some of them can be used to mask deficiencies in some honey quality properties. Diastases/amylases are such proteins, and their activity, a measure of honey freshness, can decrease in time or due to processing. To our knowledge, we for the first time specifically identify foreign amylases in honey. However, this study provided new information on other non-honey bee proteins in honey. Thus, this study is also of importance due to its identification of plant and aphid proteins and catalase-related proteins. This study provides a clue explaining the controversial presence of catalase in honey, since catalases can be identified and their origin determined via proteomics. [Display omitted] • Label-free proteomics enables comprehensive identification of markers in honey. • Proteomics accurately identifies artificially added amylases to adulterated honey. • We found that three different amylases were used to adulterate investigated honeys. • The approach we present can meet the need for accurate honey authentication. • An array of plant-, aphid- and catalase-related protein hits were found. [ABSTRACT FROM AUTHOR]

Aphid honeydew can reduce fungicide effectiveness against necrotrophic pathogens of wheat under controlled conditions. In 1988 and 1989, field experiments were carried out at different locations in The Netherlands, to assess the interference of honeydew with fungicide effectiveness under field conditions, and to establish whether honeydew consumption by naturally occurring saprophytes could prevent this effect. Different combinations of chemicals were used to create differences in saprophytic population densities and aphid populations, which were expected to result in differences in the amount of honeydew and other nutrients on the leaves. In two of the experiments, Septoria nodorum was the only necrotrophic pathogen present; in the other two the only necrotroph was S. tritici. On several sampling dates, the effect of the fungicides was significantly enhanced by addition of insecticide, most often when the saprophytes were reduced by maneb/anilazine. This effect of insecticide is ascribed to prevention of interference of honeydew with fungicide activity, and not to a direct effect of insecticide, as insecticide alone had no effect on necrosis. On the basis of the fact that interference of honeydew with fungicide activity was most apparent when saprophytic population densities were reduced, it is concluded that the naturally occurring saprophytes can generally prevent the effect of honeydew. The same interactions are likely to occur between other nutrients and fungicides, and it is therefore argued that the naturally occurring saprophytes should be protected by elimination of harmful chemicals. [ABSTRACT FROM AUTHOR]

• Differentiation between honeydew and chestnut honey using multivariate analysis. • Castanea , Cytisus , color, RSA, Mg and trehalose variables dominated grouping by PCA. • Honeydew and chestnut (97.6%) honey were correctly classified by LDA. Oak honeydew and chestnut honeys often share the same production area in Atlantic landscapes. Consequently these honeys have common physicochemical properties and pollen composition, making their differentiation by routine methods, a difficult task. The increase in the demands of consumers for clear honey labelling, identifying floral make-ups and the substantial health properties of both honey types, make it necessary to improve methods to differentiate the honeys. Statistical multivariate techniques were used to study the differences in the physicochemical composition and pollen spectra between chestnut honey and oak honeydew honey. Palynological analysis, moisture, pH, electrical conductivity, hydroxymethylfurfural, diastase number, colour, phenolic content, minerals and sugars were used for this purpose. The variables that had more weight in the differentiation by principal component analysis were Castanea , Cytisus type, CIELab coordinates (a* and L), RSA, Mg and trehalose; 97.6% of the honey samples were correctly classified by linear discriminant analysis. [ABSTRACT FROM AUTHOR]