Dark Honey Research Articles

Effect of honey on purified equine myeloperoxidase activity and superoxide radical production in activated Polymorphonuclear neutrophils

Three Algerian honey samples (nectar honey, mixed honey and honeydew honey) were analysed for their total phenolic content (TPC) using the Folin–Ciocalteu reagent and total flavonoid content (TFC) by the aluminium chloride method. The antioxidant activity was tested both against reactive oxygen species (ROS) produced by phorbol 12-myristate 13-acetate (PMA)-stimulated equine polymorphonuclear neutrophils (PMNs) and on purified equine myeloperoxidase (MPO) enzyme activity. The ROS production by stimulated PMNs was measured by lucigenin-enhanced chemiluminescence. Specific immunological extraction followed by enzymatic detection (SIEFED) was used to measure specifically the activity of equine MPO. Nectar honey, mixed honey and honeydew honey had TPCs of 59.52 ± 1.31, 68.36 ± 1.20 and 122.76 ± 4.20 mg gallic acid equivalents (GAE)/100 g honey, respectively (mean ± SD). As for the TPC, the highest TFC was observed for honeydew honey [20.55 ± 0.72 mg catechine equivalents (CE)/100 mg honey], followed by mixed honey (7.47 ± 0.07 CE/100 mg honey) and nectar honey (4.80 ± 0.08 CE/100 mg honey). All the tested honeys displayed a dose-dependent inhibitory effect on the oxidant activities of PMNs. By the SIEFED technique, it was shown that most of the honeys interact directly with MPO: the light honeys (nectar honey and mixed honey) were inhibitors of MPO activity, while the dark honey had less inhibiting effect and even behaved as an enhancer of MPO activity at high concentrations.

Phenolic Profile and Antioxidant Activity of Polish Meads

The purpose of this study was to evaluate phenolic profile and antioxidant activity of ten different meads of 1:1 and 1:2 types, produced with addition of fruit juices, root spices, and herbs. The total phenolic content in meads varied from 15.27 to 70.80 mg/dm3. The meads originated from dark honeys exhibited the highest antioxidant activity. The predominant phenolic compounds in meads were hydroxybenzoic acids, especially gallic and protocatechuic acid, originated mainly from honeys. Whereas, among the hydroxycinnamic acids, the major phenolic was chlorogenic acid, derived mainly from plant additives used in meads production. A principal component analysis was applied in order to differentiate the investigated meads. The 1:2 meads type could be best described by chlorogenic acid. Among the 1:1 meads type, those made from the dark honeys could be best described by gallic, p-coumaric, and protocatechuic acid while those made with addition of blackcurrant and raspberry juice could be described by caffeic and ferulic acid.

Reduced SNP panels for genetic identification and introgression analysis in the dark honey bee (Apis mellifera mellifera).

Beekeeping activities, especially queen trading, have shaped the distribution of honey bee (Apis mellifera) subspecies in Europe, and have resulted in extensive introductions of two eastern European C-lineage subspecies (A. m. ligustica and A. m. carnica) into the native range of the M-lineage A. m. mellifera subspecies in Western Europe. As a consequence, replacement and gene flow between native and commercial populations have occurred at varying levels across western European populations. Genetic identification and introgression analysis using molecular markers is an important tool for management and conservation of honey bee subspecies. Previous studies have monitored introgression by using microsatellite, PCR-RFLP markers and most recently, high density assays using single nucleotide polymorphism (SNP) markers. While the latter are almost prohibitively expensive, the information gained to date can be exploited to create a reduced panel containing the most ancestry-informative markers (AIMs) for those purposes with very little loss of information. The objective of this study was to design reduced panels of AIMs to verify the origin of A. m. mellifera individuals and to provide accurate estimates of the level of C-lineage introgression into their genome. The discriminant power of the SNPs using a variety of metrics and approaches including the Weir & Cockerham’s FST, an FST-based outlier test, Delta, informativeness (In), and PCA was evaluated. This study shows that reduced AIMs panels assign individuals to the correct origin and calculates the admixture level with a high degree of accuracy. These panels provide an essential tool in Europe for genetic stock identification and estimation of admixture levels which can assist management strategies and monitor honey bee conservation programs.

English

The effect of physicochemical properties (moisture content, total acidity, total phenolic content and viscosity) of honey on the microbial shelf stability of cassava-wheat composite bread was investigated. The percentage weights of the sugar (sucrose) required in the formulated recipe was substituted with different types of honey at the same level (70% sucrose: 30% honey). Freshly baked and cooled cassava-wheat composite bread loaves were stored or shelf at ambient temperature and the total aerobic bacteria and mould counts were determined after 4 and 6 days. The physicochemical analyses revealed that the total acidity, total phenolic content, moisture and viscosity of the different types of honey used varied. The physicochemical properties of the various honey used influenced the microbial shelf stability of the cassava-wheat composite bread. Highest total aerobic bacteria counts of 0.25 × 104 cfu/g was recorded for the cassava-wheat composite bread baked with Hamba honey 2 which had significant (p ≤ 0.05) lowest total acidity (42.41 mEq/kg) and total phenolic contents (48.97 GAE/100 g) as well as significant (p ≤ 0.05) highest % moisture after 4 days of storage. However, the incorporation of dark and golden honey with higher total acidity and total phenolic contents compared with other types of honey used, resulted in the least mould counts of 0.42 × 104  and 0.45 × 104 cfu/g, respectively, after 6 days of storage. The physicochemical properties of honey could enhance the microbial shelf stability of baked bread if the minimum inhibitory concentration of the honey after baking is employed.    Key words: Honey, cassava-wheat composite bread, microbial shelf stability. &nbsp

A study of pollen from light honeys produced in Piauí State, Brazil

Colour is one of the features that differentiate the types of honeys, perhaps the attribute that has the most power of attractiveness to consumers, who tend to value light honeys. Nevertheless, there is no research to date showing the botanical origin of light honeys from Piauí, and neither separating them from the dark ones, using the pollen spectrum. Aiming to characterise botanical origin from pollen grains, samples of light honey produced in the state of Piauí, and also investigating the possibility of differentiation between light and dark honey through pollen spectrum analysis, 26 samples classified as light by spectrophotometry (≤50 mm Pfund), along with six dark samples, were acetolised with adaptation of solution/rinsing with ethanol. Following that, the pollen residue was analysed under an optical microscope. The obtained data were subjected to ordination through a principal coordinate analysis and a detrended correspondence analysis. A total of 151 pollen types were identified in samples of light honeys, representing 41 botanical families, three of which are noteworthy: Euphorbiaceae, Fabaceae and Rubiaceae. Among the types present in 50% or more of the samples, and the highest relative frequency, the following are significant: Mimosa caesalpiniifolia, Mimosa pudica, Mimosa tenuiflora/verrucosa, Pityrocarpa moniliformis and Syagrus. Of the 26 analyzed samples of light honey, 13 were considered monofloral: seven of P. moniliformes, five of M. caesalpiniifolia and one of M. pudica. The ordering analysis revealed the existence of groups between light honeys, two of which are unrelated to dark honeys. Plants of the Fabaceae family, especially the genera Mimosa and Pityrocarpa, contribute greatly to the production of light honeys in Piauí State, Brazil.

Physicochemical Characteristics of Saudi Arabian Locally Produced Raw and Diluted Honeys and Their Relations to Antimicrobial Activity

The physicochemical characteristics and antibacterial activity of Saudi Arabia honeys were studied for the first time. The levels of free and total acidity, pH, ash and moisture content were in the range 1.6 ±0.17 - 15.1 ±0.1 meq/kg, 2.77 ± 0.06 - 5.37 ±0.04, 1.1 ±0.02 – 1.7 ±0.03 % and < 18.0 %, respectively. Lovibond comparator color scale (P, mm) of samples was ranged from water white (P=0.0-1.3), extra light Amber (P=38.14-46.57), light Amber (P=60.39-75.54), Amber (P=86.72-110.08), dark (P=142.39-348.44) and very dark shade (P= 541.84). Dark honeys showed excellent inhibitory effects against bacterial growth. Excellent correlation between color of raw and diluted (>10.0%m/v) honey and antimicrobial activity was noticed. Honey species from different floral sources posses’ strong antioxidant and anti bacterial activities and are scavengers of active oxygen species.

Practical procedure for discriminating monofloral honey with a broad pollen profile variability using an electronic tongue

Colour and floral origin are key parameters that may influence the honey market. Monofloral light honey are more demanded by consumers, mainly due to their flavour, being more valuable for producers due to their higher price when compared to darker honey. The latter usually have a high anti-oxidant content that increases their healthy potential. This work showed that it is possible to correctly classify monofloral honey with a high variability in floral origin with a potentiometric electronic tongue after making a preliminary selection of honey according their colours: white, amber and dark honey. The results showed that the device had a very satisfactory sensitivity towards floral origin (Castanea sp., Echium sp., Erica sp., Lavandula sp., Prunus sp. and Rubus sp.), allowing a leave-one-out cross validation correct classification of 100%. Therefore, the E-tongue shows potential to be used at analytical laboratory level for honey samples classification according to market and quality parameters, as a practical tool for ensuring monofloral honey authenticity.

Evaluation of Heavy Metals and Polycyclic Aromatic Hydrocarbons in Honeys from Different Origins

A survey of honey samples from different geographical and botanical origins, including some samples collected from a fire-affected area in Spain, was conducted to assess their content of heavy metals and polycyclic aromatic hydrocarbons (PAHs). The levels of the determined toxic elements (Pb, Cd, As, and Sn) were low and were in the range of those reported by other studies. In our work the total amount of heavy metals and Pb was higher in dark honeys than in pale honeys. In the collected samples, no detectable levels of the 15 PAHs studied were found. The obtained data served to assess the levels of heavy metals and PAHs in honey samples from different geographical and environmental origins and to contribute to the scarce data about pollutant content of this matrix. In light of these results, the analyzed samples do not pose any serious concern to human health, and the data obtained in this study could serve to contribute to the establishment of specific maximum limits for honey.

Physicochemical characterization and antioxidant activity of 17 commercial Moroccan honeys

In this study, 17 commercial honey samples from Morocco were analyzed. Four samples did not meet the international physicochemical standards due to high hydroxymethylfurfural content and low diastase activity. Phenol content varied from 163.82 mg gallic acid equivalent (GAE)/kg in citrus honey to 923.70 mg (GAE)/kg in thyme honey from Rachidia; flavonoid content ranged from 4.26 mg quercetin equivalent (QE)/kg in citrus honey to 139.62 mg QE/kg in black cumin honey. Black cumin honey had the highest peroxyl scavenging activity; oregano (from Zaraphyt) and thyme honeys (from Rachidia) had the highest ABTS (2,2′-azino-bis[3-ethylbenzothiazoline-6-sulphonic acid]) scavenging activity; and thyme honey (Saouira) had the highest NO scavenging capacity. The antioxidant activity of Moroccan honeys was correlated with the phenol, flavonoid, and melanoidin contents. Dark honeys had higher antioxidant activity than light honeys. Samples with high sodium levels had lower free radical scavenging activity. On the other hand, calcium and magnesium increased the ABTS and peroxyl scavenging capacity, respectively, of honey samples. According to cluster and discriminant analyses, the honey samples were grouped in three clusters with respect to the phenol, flavonoid, melanoidin, proline, mineral and sugar contents, and free radical scavenging capacity.

Genetic integrity of the Dark European honey bee (Apis mellifera mellifera) from protected populations: a genome-wide assessment using SNPs and mtDNA sequence data

SummaryThe recognition that the Dark European honey bee, Apis mellifera mellifera, is increasingly threatened in its native range has led to the establishment of conservation programmes and protected areas throughout western Europe. Previous molecular surveys showed that, despite management strategies to preserve the genetic integrity of A. m. mellifera, protected populations had a measurable component of their gene pool derived from commercial C-lineage honey bees. Here we used both sequence data from the tRNAleu-cox2 intergenic mtDNA region and a genome-wide scan, with over 1183 single nucleotide polymorphisms (SNPs), to assess genetic diversity and introgression levels in several protected populations of A. m. mellifera, which were then compared with samples collected from unprotected populations. MtDNA analysis of the protected populations revealed a single colony bearing a foreign haplotype, whereas SNPs showed varying levels of introgression ranging from virtually zero in Norway to about 14% in Denmark. Introgression overall was higher in unprotected (30%) than in protected populations (8%), and is reflected in larger SNP diversity levels of the former, although opposite diversity levels were observed for mtDNA. These results suggest that, despite controlled breeding, some protected populations still require adjustments to the management strategies to further purge foreign alleles, which can be identified by SNPs.

Identifying suitable queen rearing sites of Apis mellifera mellifera at a regional scale using morphometrics

SummaryHoney bee decline in Europe has forced beekeepers to re-evaluate their management practices and breeding methods. Evidence suggests that the dark western honey bee (Apis mellifera mellifera) may be better adapted to the British climate, and consequently presents the potential for greater resistance to disease than other strains. Substantial hybridization of A. m. meliifera has taken place in Great Britain due to imports of subspecies from southern Europe (A. m. ligustica and A. m. carnica). This study evaluated the extent of hybridization at a regional scale in North Wales using morphometrics. By analysing honey bee wing venation and determining the cubital index (CI) and the discodial shift angle (DisA) the subspecies of each bee was determined. Analyses of 1830 wings from 61 colonies indicated a mean CI of 1.86 and a mean DisA of -0.37°. Most colonies consisted of hybrids of A. m. mellifera and A. m. ligustica with a slight predominance of A. m. mellifera traits. Across all 61 colonies, 43.2% of bee colonies presented A. m. mellifera traits, although this masked considerable variation between colonies (3% to 93%). Spatial analysis identified areas where queen release in breeding programmes would be expected to increase the predominance of A. m. mellifera traits.

Antioxidant activity, color characteristics, total phenol content and general HPLC fingerprints of six Polish unifloral honey types

Total phenolic content, antioxidant activity (two assays: 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and ferric reducing antioxidant power (FRAP)), and color coordinates (CIE (Commission Internationale de l'Eclairage) L*a*b*) for six Polish unifloral honeys (black locust, rapeseed, lime, goldenrod, heather and buckwheat) were assessed for several batches of the same honey type and statistically evaluated. Total phenolic content (121.6–1173.8 mg GAE/kg) was similar to the values previously reported for other European honeys and it was also correlated with the color parameters as well as antioxidant activity. The honeys' color ranged from pale yellow to dark amber. Dark buckwheat honey with much higher phenolic content (1113.0 mg GAE/kg) exhibited higher antioxidant activity (5.7 mmol Fe2+/kg and 1.2 mmol TEAC/kg). CIE L*a*b* color coordinates can be helpful for identifying and distinguishing between several honey types, such as heather and buckwheat, but almost no differences were found among very light honeys (rapeseed, goldenrod, black locust and lime). High-performance liquid chromatographic (HPLC) analysis revealed general characteristic fingerprints of Polish unifloral honeys with significant differences among the samples of other honey types.

Nutraceutical properties of Romanian heather honey

Purpose – The main purpose of this study is to create a complete physico‐chemical characterisation of Romanian heather honey.Design/methodology/approach – A total of 30 samples of heather honey were harvested from three different geographical areas (Fântânele, Calaţele, Marisel) from Transylvania region (Romania). This study contains a complete characterization of heather honey regarding its physico‐chemical composition, total phenols content, flavonoids content, antioxidant activity (expressed as radical scavenging activity – RSA) and micro‐ and macroelements content.Findings – The results obtained for the total phenols content and total flavonoids demonstrate that honey samples have good bioactive properties and the antioxidant activities are similar to those of dark honeys. Heather honeys normally have a high content of minerals, having their origin in soil. All quantified minerals in heather honey presented values higher that those reported for other types of honey.Practical implications – Heather hon...

Floral Origin Identification and Amino Acid Profiles of Chinese Unifloral Honeys

The aim of the current study was to investigate the properties of Chinese honeys. A total of 33 honeys were collected from various botanical and geographical sources in China. Nine unifloral honeys were identified as Acacia, Vetch, Linden, Coptidis, Red date, Astragalus, Codonopsis, Eriobotrya, and Eucalyptus according to their pollen granule characteristics. The chemical properties of free amino acids were further assessed; the total amino acid contents ranged from 240.7 mg/kg in light honey to 812.6 mg/kg in dark honey. Remarkable variations in proline and total amino acid contents were demonstrated in honeys from different botanical or geographical sources.

Effect of Honey a Natural Sweetener with Several Medicinal Properties on the Attributes of a Frozen Dessert Containing the Probiotic <i>Lactobacillus acidophilus</i>

Lactobacillus acidophilus has several health advantages. Honey has several medicinal properties and is also a natural sweetener which could be used in frozen desserts. There are various types of honey based on color namely, light, amber and dark. Influence of honey on attributes of a probiotic frozen dessert is not known. The objective was to study the effect of light, amber colored and dark honey on the Lactobacillus acidophilus counts and quality attributes of probiotic ice cream. Ice creams were manufactured with use of Lactobacillus acidophilus at 50 g of frozen culture concentrate per 7.75 liters of ice cream mix and with the use of light or amber or dark honey individually. Control had no honey and was sweetened with sugar. Use of honey increased Lactobacillus acidophilus counts and viscosity, while decreased pH and melt down volume. Light honey ice cream had flavor and appearance scores comparable to the control vanilla ice cream. Light honey can be recommended for the manufacturing Lactobacillus acidophilus probiotic ice creams thus having a frozen dessert with the health advantageous medicinal properties of honey.

Characterization Of Antioxidants And Antioxidative Properties Of Various Unifloral Honeys Procured From West Bengal, India.

The present study deals with the investigation of erstwhile undocumented fifty four samples of West Bengal honey from ten different floral origins sesame (Sesamum indicum), hizal (Barringtonia acutangula), mustard (Brassica spp.), drumstick (Moringa oleifera), litchi (Litchi chinensis), eucalyptus (Eucalyptus spp.), karanza (Pongamia glabra), khalsi (Aegiceras corniculatum), goran (Ceriops decandra) and bain (Avicennia officinalis) for its quantification and comparison of antioxidative capacity by chemometrics. The average total polyphenol and flavonoid content of honeys varied from 9.9 ± 0.6 (bain) to 44.7 ± 2 mg (hizal) gallic acid equivalent and 5.12 ± 0.23 (drumstick) to 19.4 ± 1.38 (bain) mg of quercetin per 100 g respectively. Dark brown hizal honey with ABS450 value of 2055.6 mAU exhibited the most potent DPPH (2, 2-diphenyl-1picrylhydrazyl) radical scavenger (IC50 = 23.92 ± 1.12 mg/mL) and a FRAP (ferric reducing ability of plasma) value of 381 ± 1.9μM Fe (II).

Mineral content and physical properties of local and imported honeys in Saudi Arabia

In addition to color, ash and electrical conductivity (EC), the levels of 14 minerals were investigated in 23 varieties of honey from Saudi Arabia and six other countries. The quantities of the macrominerals obtained were as follows (in ppm): K (298.60–491.40), Mg (80.70–199.30), Ca (60.75–99.95), P (21.10–33.29), and Na (15.69–26.93). The quantities of trace minerals were as follows (in ppm): Fe (67.18–98.13), I (12.61–94.68), Mn (4.15–6.04), Zn (3.44–5.72), Li (1.15–4.26), Co (1.00–1.32), and Ni (0.15–0.67). The quantities of the heavy metals Pb and Cd were found to be 0.06–0.23 and 0.00–0.16, respectively. The values of the tested elements—color, ash and EC—varied among the tested honeys according to their botanical origin. Dark honeys, especially acacia honeys, had higher elemental content and EC values than lighter ones. Saudi and Yemeni seder honeys exhibited no distinctive characteristics in their tested parameters. The levels of heavy metals indicated that the tested honeys were safe for human consumption.

Botanical Origin Causes Changes in Nutritional Profile and Antioxidant Activity of Fermented Products Obtained from Honey

Honey as rich source of enzymatic and nonenzymatic antioxidants serves as health-promoting nutrient in the human body. Here, we present the first time a comparative study of nutritional profiles (e.g., acidities, sugar, organic acid profile, total polyphenolic, flavonoid content) for different unifloral, multifloral honeys and their fermented products, in correlation with their antioxidant activity. Additionally, an optimized method for HPLC separation of organic acids from honey was established. The total phenolic content of honey samples varied widely among the honey types compared to fermented products. High amounts of total flavonoids were quantified in heather honey, followed by raspberry, multifloral, black locust, and linden honey. A positive correlation between the content of polyphenols, flavonoids, and antioxidant activity was observed in honey samples. After fermentation, the flavonoid content of dark honey fermented products decreased significantly. Black locust and linden honeys are more suitable for fermentation because the decrease in antioxidant substances is less pronounced.

Mercury in fruiting bodies of dark honey fungus (Armillaria solidipes) and beneath substratum soils collected from spatially distant areas

This paper reports data on bioconcentration potential and baseline mercury concentrations of fruiting bodies of dark honey fungus (Armillaria solidipes) Peck and soil substrate layer (0-10 cm) from 12 spatially distant sites across Poland. Mercury content of caps, stipes and soil samples were determined using validated analytical procedure including cold-vapor atomic absorption spectroscopy after thermal decomposition of the sample matrix and further amalgamation and desorption of mercury from gold wool. Mean mercury concentrations ranged from 20 ± 8 to 300 ± 70 ng g(-1) dry weight (dw) in caps, from 20 ± 6 to 160 ± 40 ng g(-1) dw in stipes, and in underlying soil were from 20 ± 2 to 100 ± 130 ng g(-1) dw. The results showed that stipes mercury concentrations were 1.1- to 1.7-fold lower than those of caps. All caps and the majority of stipes were characterized by bioconcentration factor values > 1, indicating that dark honey fungus can be characterized as a moderate mercury accumulator. Occasional or relatively frequent eating of meals including caps of dark honey fungus is considered safe in view of the low total mercury content, and the mercury intake rates are below the current reference dose and provisionally tolerable weekly intake limits for this hazardous metal.

Determination of the hydrophobic fraction of Ca, Fe, Mg and Zn in dark color honeys using solid phase extraction and flame atomic absorption spectrometry

In this study, the hydrophobic fraction of Ca, Fe, Mg and Zn in dark honeys was assessed by means of solid phase extraction using silica gel based material with monomerically bonded phenyl active groups (Discovery® DSC-Ph tubes). It was found that Fe is associated with this fraction, likely polyphenolic compounds, to the highest degree. The contribution of the hydrophobic fraction to the total content of this element in analyzed honeys accounted for 7-43%. The reliability of these results was verified using for solid phase extraction silica gel based material with polymerically bonded octadecyl active groups (SupercleanÔ ENVI DSC-18). Additionally, a strong positive correlation was established between the concentration of Fe in the hydrophobic fraction assessed and the optical density of dark honeys, indicating a possible contribution of blue complexes of this metal with phenolic substances to the overall color of honey.