Linden Honey Research Articles

New method for risk assessment in environmental health: The paradigm of heavy metals in honey

The release of heavy metals into the natural environment creates problems due to their persistence. They can accumulate in the food chain presenting a dangerous sign for ecosystems and human health. The metals in honey could be of agrochemical or industrial origin. Regular consumption of honey and bee products contaminated with various pollutants in high concentrations can cause serious health problems due accumulation of toxic substances in the body. In the current study, we aimed to determine the concentrations of chromium, cadmium, zinc, copper, lead and nickel in four types of honey (linden, acacia, rapeseed and polyfloral honey) and soil collected from three regions with different degrees of pollution. For the risk characterization, we used a new methodology that calculated the corrected estimated daily intake and the source hazard quotient for each metal and the adversity-specific hazard index. There was a strong influence of the degree of environmental pollution on the level of contaminants in the honey samples. In the case of a single chemical assessment, an HQ above 10 was obtained for Cd in linden, rapeseed and polyfloral honey from area 1 and an HQ above 1 was obtained for Cd in the other honey samples from the 3 areas, for Cu in all honey samples from all the 3 areas, for Pb in linden, rapeseed and polyfloral honey from area 1 and for Cr in linden honey for area 2. HIA calculated as a sum of all HQS of heavy metals in food reveals an increase and moderate risk for nephrotoxicity, bone demineralisation, cardiotoxicity, developmental toxicity, small decrease in body weight or body weight gain after consumption of honey impurified with heavy metals. A strict monitorization of heavy metals in honey samples from farmers should be done in order to protect the consumers.

Исследование реологических свойств майонеза с нетрадиционным сырьем

Rheological measurements are used in the food industry to determine physical characteristics of raw materials, as well as semi-finished and finished products. We aimed to study the effects of ingredients and homogenization parameters on the rheological properties of mayonnaise prepared with pumpkin and rice oils, as well as various honeys.
 Mayonnaise samples were prepared with non-traditional ingredients, namely cold-pressed pumpkin seed oil, refined rice oil, and four varieties of honey (acacia, linden, forest, and spring). The samples were made in the traditional way on an Ultra Turrax T25 IKA homogenizer (3500–24 000 rpm). The rheological properties of honey and mayonnaise were determined on a Brookfield rotational viscometer.
 Forest honey had the highest viscosity, while linden honey had the lowest viscosity, compared to the other honeys. The sample of mayonnaise with forest honey had the highest effective viscosity (3.427 Pa·s) and consistency (101.26 Pa·sn). The use of whey powder provided mayonnaise with the most optimal rheological parameters. Of all carbohydrates, inulin HD had the best effect on the consistency of mayonnaise, with effective viscosity of 2.801 ± 0.001 Pa·s and a flow index of 0.2630 ± 0.0020. Disaccharides provided mayonnaise with higher viscosity and consistency than monosaccharides. Mayonnaise with fresh egg yolk had higher viscosity (2.656 ± 0.002 Pa·s) and consistency (65.640 ± 0.004 Pa·s) than the samples with other egg products. The rheological characteristics of mayonnaise were also determined by the homogenization time and rotor speed. Increasing the time from 2 to 4 min at 10 000 rpm raised the emulsion’s viscosity and consistency from 6.253 to 8.736 Pa·s and from 77.42 to 134.24 Pa·sn, respectively, as well as reduced the flow index from 0.2628 to 0.1995. The rotor speed of 10 000–12 000 rpm was optimal for mayonnaise with pumpkin and rice oils and honey.
 The studied samples of mayonnaise with pumpkin and rice oils, as well as honey, belong to non-Newtonian systems and pseudoplastic fluids. The empirical flow curves can be adequately described by the Herschel-Bulkley model. Our results can significantly increase the efficiency of mayonnaise production, improve its quality, and reduce production costs.

The Antioxidant Activity of Monofloral Honey and Its Awareness Among Urban Consumers in Slovakia

The main objective of this paper was to determine antioxidant activity in various types of monofloral honey produced in Slovakia and to identify consumer behaviour and awareness of biological activity of honey among urban consumers. Research is based on primary data obtained by conducting analytical research (DPPH and TPC) involving 37 samples of monofloral honey and consumer research (n =1940 Slovak honey consumers living in urban areas). Results showed that the highest antioxidant activity was detected in buckwheat honey and honeydew honey, while the lowest was indicated in acacia honey. Consumer research showed that 57.5% of respondents are aware of antioxidant activity in honey and 12,9% indicated that they are not aware of any biological activity. Urban consumers tend to consume honey few times per month or week. Higher annual consumption is typical for consumers older than 42 years. The most preferred honey is acacia honey followed by honeydew and linden honey. The majority of respondents seeks on the honey label information about honey type, producer and origin while the information about nutrition or additional information (website, social media etc.) are not so important.

Determination of volatile compound profiles and physico-chemical analysis of linden and acacia Czech honey

In this study 12 acacia and 12 linden honey samples from the Czech Republic were analyzed with a chemometric and volatile compound profiles approach. The results of electrical conductivity (17.4 and 65.1 mS/m), free acidity (12.5 and 24.5 meq/kg), diastase activity (12.6 and 18.8 DN), colour (21.5 and 47.8 mm Pfund), hydroxymethylfurfural (HMF) (11.5 and 3.5 mg/kg), fructose (45.1 and 36.3 g/100g), fructose + glucose (F + G) (76.7 and 69.3 g/100g) content and fructose/glucose ratio (1.4 and 1.1) showed statistically significant differences (p < 0.05) between acacia and linden honey, respectively. The physico-chemical properties and pollen profiles were in compliance with the description of European monofloral honey, except for acacia honey due to the low proportion of acacia pollen (2.8 − 10.3%). According to volatile compounds analysis by head-space solid phase micro-extraction coupled with gas chromatography − mass spectrometry (HS-SPME/GC-MS), nine key volatile substances were selected from more than 100 volatile compounds present in the analysed samples for evaluation as markers of botanical origin typical of the most common plant nectar sources in the Czech Republic. Further, the non-targeted analysis combined with Principal Component Analysis (PCA) revealed trends and outliers within all chromatography data obtained for 24 honey samples. Cis-linalool oxide and β-linalool have been confirmed as markers of acacia honey, while carvacrol and p-cymenene were found almost exclusively in linden honey. The results demonstrated that the chemometrics with the non-targeted and targeted volatile compounds analysis approach is reliable and accurate for the classification of honey of various botanical origins.

TRAKYA YÖRESİ BALLARININ MİNERAL İÇERİĞİ VE BAZI TİPİK KALİTE PARAMETRELERİ AÇISINDAN DEĞERLENDİRİLMESİ

Çalışmanın amacı, Trakya bölgesi çiçek ve salgı ballarının mineral içeriği ve bazı kalite parametrelerinin belirlenmesidir. Bu amaçla Trakya Bölgesi'nde yerel olarak üretilen 16 adet ayçiçeği, 2 adet karaçalı, 3 adet kanola, 3 adet meşe ve 1 adet ıhlamur balı olmak üzere toplam 25 adet bal örneğinde 8 farklı mineral (Ca, Fe, K, Mg, Na, Zn, P, Se) düzeyi ve bazı tipik kalite parametreleri (çözünür kuru madde, pH, elektriksel iletkenlik, serbest asitlik, HMF ve şeker içeriği) analiz edilmiştir. Bal örneklerinin mineral içerikleri İndüktif Eşleşmiş Plazma Optik Emisyon Spektrometresi (ICP-OES) ile analiz edilmiştir. Ballarda en çok bulunan mineraller sırasıyla potasyum, fosfor ve kalsiyum olup 18.91–1018.74, 244.40–429.98 ve 8.50–140.82 mg/kg arasında belirlenmiştir. Kalite parametreleri ortalama olarak pH 4.42 (3.86-6.54), çözünür kuru madde 81.4°Bx (79.3-83.0), serbest asitlik 15.66 mEq/kg (9.00-28.00), HMF 13.00 mg/kg (0.16-33.45), elektriksel iletkenlik 595 μS/cm (207-1376), glukoz %33.66 (25.51-38.58), fruktoz %38.17 (33.32-47.91), sakkaroz %0.17 (0.01-0.67) olarak tespit edilmiştir.

Establishment and application of quantitative method for 22 organic acids in honey based on SPE-GC–MS

Honey, a natural healthy liquid bee product, is rich in amino acids, vitamins, and other essential nutrients. Different origin honeys also varied in organic acids. The objective of this study is to establish an efficient solid-phase extraction-gas chromatography–mass spectrometry (SPE-GC–MS) method to eliminate interference of sugar and other impurities for accurately estimating 22 organic acids in honey by optimizing extraction, purification, derivatization, and gas chromatography–mass spectrometry (GC–MS) analytical conditions. After being extracted, purified and derivatized, organic acids in honey were qualified and quantified by GC–MS. This method was evaluated experimentally, and the results showed that, within a certain concentration range, the standard curve linear relationship was satisfactory (R2 > 0.9942), and the target organic acid recovery rate was 86.74% ~ 118.68%. Besides, precision (relative standard deviation, RSD = 2.98% ~ 13.42%), detection limit (LOD = 0.002 ~ 0.2 mg kg−1), and quantification limit (LOQ = 0.008 ~ 0.5 mg kg−1) met the target requirements. Also, based on this analytical method, the organic acids in five types of honey (acacia, jujube, vitex, canola and linden honey) were estimated. Notably, they all contained 22 different kinds of organic acids, and significant differences (p < 0.05) in the organic acid content and composition among different honey varieties were observed. PCA analysis showed that the five honeys could be differentiated based on the content of 22 organic acids.

Botanical origin identification and adulteration quantification of honey based on Raman spectroscopy combined with convolutional neural network

A non-destructive and reliable spectroscopic analysis method was proposed for detecting honey fraud based on Raman spectroscopy and convolutional neural network (CNN). Acacia, litchi and linden honey were adulterated with high fructose corn syrup (HFCS), rice syrup (RS), maltose syrup (MS) and commercial blended syrup (BS) at different concentrations, respectively. Spectra were collected from 60 authentic honeys and 360 adulterated honeys. Dimensionality reduction algorithms provided an overview and visualization of the spectral dataset. The strategy of this study was that the botanical origins and adulteration concentrations of unknown samples were obtained through a combination of qualitative and quantitative models, regardless of the types of honey and contaminant. The CNN classification model and chemometric algorithms achieved more than 99.76% accuracy for honey matrix identification, while the CNN quantitative models kept the coefficients of determination (R2p) and root mean square errors of prediction (RMSEP) above 0.95 and below 4.25, respectively. CNN achieved significantly better performance than chemometric algorithms and met the routine detection requirements of honey. The proposed method provides a promising alternative to combat honey fraud.

Antibacterial and Biofilm Degradation Effects of Hungarian Honeys Linked With Botanical Origin, Antioxidant Capacity and Mineral Content.

The aim of the study was to assess the impact of four unifloral honeys on the food-borne pathogens Pseudomonas aeruginosa and Staphylococcus aureus, by analyzing the honeys’ antibacterial and biofilm degradation effects, as well as their antioxidant activity and element content. Linden and milkweed honeys represented light colored honeys, while goldenrod and chestnut honeys the darker ones. The botanical origin of the honeys and the relative frequency of their pollen types were established with melissopalynological analysis. The antioxidant capacities were calculated by two single electron transfer based methods (TRC – Total Reducing Capacity and TEAC – Trolox Equivalent Antioxidant Capacity) and a hydrogen atom transfer based assay (ORAC – Oxygen Radical Absorbance). The amount of four main macro- and two microelements was quantified. The antibacterial activity was determined by minimum inhibitory concentration (MIC) and membrane degradation assays. Furthermore, the biofilm degradation power of the samples was studied as well. The light colored linden honey with the lowest TRC and TEAC, but with the highest ORAC antioxidant activity and high element content showed the best antibacterial and biofilm degradation effects. Meanwhile, the dark colored chestnut honey with significantly higher single electron transfer based antioxidant capacities, with high element content, but lower ORAC showed significantly higher MIC and lower membrane degradation activity than linden honey. In case of biofilm degradation, both honey types gave similarly high inhibitory effect. Goldenrod honey was similarly effective regarding its MIC properties like chestnut honey, but had significantly lower antioxidant potential and ability to disrupt bacterial membranes and biofilms. Milkweed honey was the honey type with the lowest bioactivity and element content. The honeys, unequivocally characterized by their antioxidant characters and element content, displayed different antibacterial and biofilm degradation effects. In addition, some honey traits were found to be good predictors of the antimicrobial potential of honeys: ORAC assay showed correlation with the MIC values of both bacteria, and strict correlation was found between the mineral content and the antibiofilm activity of the studied honeys. Our studies indicate that unifloral honeys, such as linden and chestnut honeys, are plant-derived products with great potential as antimicrobial agents in food preservation, exhibiting remarkable antibacterial activity against food-borne pathogens.

Kaempferol-3-O-galactoside as a marker for authenticating Lespedeza bicolor Turcz. monofloral honey

Honey produced from Lespedeza bicolor Turcz. (L. bicolor) is highly valued and relatively rare, leading to adulterated or ersatz substitutes in the marketplace, with no reliable authentication methods available for enforcement of regulations. Here, we characterize the physicochemical parameters (water content, pH, sugar content, amylase activity, and 5-hydroxymethylfurfural content) in L. bicolor honey and palynological characteristics of L. bicolor pollen as reference for assessment of quality and monoflorality. Mass spectrometry with Orthogonal Partial Least Square Discriminant Analysis of chemical constituent data from L. bicolor, chaste, acacia, jujube, and linden honeys, all commonly sold in China, identified kaempferol-3-O-galactoside as a candidate chemical marker of L. bicolor honey. We validated this screening method and quantified kaempferol-3-O-galactoside in L. bicolor, but not other honeys, at concentrations between 90.2 and 430.1 µg/kg, with high sensitivity (LOD = 0.002 mg/kg), linearity (R2 ≥ 0.99), and recovery (90.2%–110.6%), supporting its use in authenticating L. bicolor honey.

Chemical Composition, Antioxidant and Antimicrobial Activity of Some Types of Honey from Banat Region, Romania.

Honey is a natural product with multiple health benefits. The paper presents the chemical characterization and the antioxidant and antimicrobial potential of ten types of honey (knotweed, linden, wild cherry, acacia, honeydew, oilseed rape, sunflower, phacelia, plain polyflora and hill polyflora) from the Banat region, Romania. We studied the water content, dry matter, impurities, acidity and pH of honey. We also determined the content of reducing sugar, minerals and flavonoids and the total phenolic content. All honey samples analysed showed good nutritional characteristics according to the standard codex for honey. From the analysis of the mineral content of the honey samples, we observed a variability in the macro and microminerals, influenced by the botanical origin, ranging between 0.25% (wild cherry honey) and 0.54% (honeydew). The toxic metals’ (Cd and Pb) levels met the standard for almost all samples analysed except for knotweed. The flavonoid content of the samples ranged from 9.29 mg QE/100 g for wild cherry honey to 263.86 mg QE/100 g for linden honey, and for polyphenols between 177.6 mgGAE/100 g for acacia honey and 1159.3 mgGAE/100 g for honeydew. The best antioxidant capacity was registered in the case of linden honey (79.89%) and honeydew (79.20%) and the weakest in acacia (41.88%) and wild cherries (50.4%). All studied honey samples showed antimicrobial activity, depending on the type of honey, concentration and strain analysed. The novelty of this study is given by the complex approach of the study of honey quality, both from the perspective of chemical attributes and the evaluation of the antimicrobial potential on specific strains in correlation with the botanical and geographical origin of the analyzed area.

Antioxidative, Antibacterial and Antiproliferative Properties of Honey Types from the Western Balkans.

This paper presents the physicochemical characteristics and antioxidative, antibacterial and antiproliferative effects of nineteen samples of different honey types (acacia, linden, heather, sunflower, phacelia, basil, anise, sage, chestnut, hawthorn, lavender and meadow) collected from different locations in the Western Balkans (Republic of Serbia, Kosovo, Bosnia and Herzegovina, and Northern Macedonia). Physicochemical parameters (moisture, pH, electrical conductivity, free acidity, and hydroxymethylfurfural [HMF]) were analysed. Based on the obtained results, all tested honey samples were in agreement with EU regulation. The antioxidant potential of honey samples was assessed by determination of total phenolic content (TPC) and evaluation of scavenging activity towards diphenilpicrylhydrazyl radicals (DPPH·). The highest phenolic content was found in basil honey (101 ± 2.72 mg GAE/100 g), while the lowest was registered in rapeseed honey (11.5 ± 0.70 mg GAE/100 g). Heather, anise, phacelia, sage, chestnut and lavender honey samples were also rich in TP, containing 80–100 mg GAE/100 g. DPPH scavenging activity varied among the samples being the highest for lavender honey (IC50 = 88.2 ± 2.11 mg/mL) and the lowest for rapeseed honey (IC50 = 646 ± 8.72 mg/mL). Antibacterial activity was estimated in vitro using agar diffusion tests and measuring minimal inhibitory concentration (MIC). Among investigated bacterial strains following resistant potencies were determined: Escherichia coli > Escherichia coli ATCC 8739 > Enterococcus faecalis > Proteus mirabilis > Staphylococcus aureus > Staphylococcus epidermidis. The linden honey from Fruška Gora (MIC values of 3.12% and 6.25% against Staphylococcus aureus and Staphylococcus epidermidis, respectively) and phacelia honey (MIC values of 6.25% and 3.12% against S. Staphylococcus aureus and Staphylococcus epidermidis, respectively) showed the strongest antibacterial activity. Antiproliferative activity was evaluated using the colorimetric sulforhodamine B (SRB) assay. The highest antiproliferative activity was obtained from linden honey sample 1 (IC50MCF7 = 7.46 ± 1.18 mg/mL and IC50HeLa =12.4 ± 2.00 mg/mL) and meadow sample 2 (IC50MCF7 = 12.0 ± 0.57 mg/mL, IC50HeLa = 16.9 ± 1.54 mg/mL and IC50HT−29 = 23.7 ± 1.33 mg/mL) towards breast (MCF7), cervix (HeLa) and colon (HT-29) cancer cells. Active components other than sugars contributed to cell growth activity.

Diversity of Monofloral Honey Based on the Antimicrobial and Antioxidant Potential.

This study aimed to investigate the antioxidant profile and the antimicrobial activity of four different types of monofloral honey (manuka (MH), brassica rapeseed (BH), acacia (AH), and linden honey (LH)) against some bacterial/fungal ATCC strains and some multidrug-resistant strains isolated from chronic otitis in dogs. For the characterisation of the antioxidant profile of each honey, we extracted the honey samples by hydroalcoholic extraction and analysed them in terms of total polyphenols (TPC), total flavonoids (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) using the spectrophotometric method. The antimicrobial activity was determined using the microdilution method at concentrations of 10%, 15%, and 20%, with the results expressed in OD (optical density) calculated as BIR% (bacterial inhibition rate)/MIR% (mycelial inhibition rate). The antioxidant characterisation of the analysed honey samples showed the highest antioxidant activity and concentrations of TPC and TFC in MH, followed by LH. MH was proven to be the most effective on most clinical isolates concerning the antimicrobial activity in comparison with BH, AH, and LH. Except for B. cepacia and P. vulgaris, all the clinical isolates were sensitive to the antibacterial activity of honey. Regarding the ATCC strains, MH 10% was the most effective in inhibiting all the strains tested except for P. aeruginosa. In conclusion, the efficacy classification in our study was MH > BH > AH > LH.

Characterization of antioxidant activity and analysis of phenolic acids and flavonoids in linden honey

Ten linden honey samples from China and Russia were analyzed in this study. Based on the determination of total polyphenol content (TPC) and total flavonoid content (TFC), the antioxidant activities of ten linden honey samples were analyzed. The results showed that the TPC and TFC in linden honey were ranged from 17.57 to 31.95 mg GAE 100 g-1 and 0.81 to 1.77 mg RE 100 g-1. The TPC and TFC of linden honey were strongly correlated with the antioxidant capacity, and the pearson’s correlation values (p≤0.01) were 0.828 and 0.770 respectively. In this work, the phenolic acids and flavonoids of linden honey were analyzed by high performance liquid chromatography (HPLC). It was found that there were a lot of lindenin and abscisic acid in linden honey. Principal component analysis (PCA) and differential characteristic analysis were used to analyze the composition differences among linden honey samples. The results obtained for TPC, TFC and antioxidant capacities of linden honeys indicate linden honey had good quality as a healthy food.

INVESTIGATION OF PESTICIDES AND HEAVY METALS FROM DIFFERENT VARIETIES OF HONEY

Bee products are essential natural resources in promoting a healthy diet with very important therapeutic properties, therefore they are used in medicine and cosmetics. That is why we set out to determine the degree of contamination with organic and inorganic pollutants in various bee products. For this purpose, different samples of honey were investigated, as follows: linden honey from Romanian accredited beekeepers (1); linden honey from H Company (2); linden honey from A Company (3) and acacia honey from accredited beekeepers (4). The concentrations of eight pesticides and five heavy metals were analyzed in the four honey samples taken. According to experimental data, there have been identified honey varieties in which the maximum permissible limits for pesticides (A Company) and heavy metals (H Company) were exceeded. As a result, a more rigorous control is required regarding the honey assortments sold on the market for consumer safety.

Determination of Floral Origin Markers of Latvian Honey by Using IRMS, UHPLC-HRMS, and 1H-NMR.

The economic significance of honey production is crucial; therefore, modern and efficient methods of authentication are needed. During the last decade, various data processing methods and a combination of several instrumental methods have been increasingly used in food analysis. In this study, the chemical composition of monofloral buckwheat (Fagopyrum esculentum), clover (Trifolium repens), heather (Calluna vulgaris), linden (Tilia cordata), rapeseed (Brassica napus), willow (Salix cinerea), and polyfloral honey samples of Latvian origin were investigated using several instrumental analysis methods. The data from light stable isotope ratio mass spectrometry (IRMS), ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS), and nuclear magnetic resonance (NMR) analysis methods were used in combination with multivariate analysis to characterize honey samples originating from Latvia. Results were processed using the principal component analysis (PCA) to study the potential possibilities of evaluating the differences between honey of different floral origins. The results indicate the possibility of strong differentiation of heather and buckwheat honeys, and minor differentiation of linden honey from polyfloral honey types. The main indicators include depleted δ15N values for heather honey protein, elevated concentration levels of rutin for buckwheat honey, and qualitative presence of specific biomarkers within NMR for linden honey.

Viable fructophilic lactic acid bacteria present in honeybee-based food products.

Fructophilic lactic acid bacteria (FLAB) are a group of lactic acid bacteria (LAB) with unique growth characteristics and are regarded as promising candidates for foods or food ingredients. The present study characterized levels of viable FLAB cells in honeybee-based food products, especially focusing on fresh honey. FLAB were recovered from 88% of fresh honey samples (harvested within a week) tested, and 29% of the fresh honey samples contained FLAB with levels of over 105 CFU/g. FLAB species found in the tested fresh honeys were mostly Apilactobacillus kunkeei and Fructobacillus fructosus. FLAB were not recovered from aged honey samples (aged over 2 weeks after harvest). Fresh comb honey and bee pollen samples occasionally contained low levels of FLAB. When FLAB were inoculated into honeys (linden honey and clover honey), their viability markedly reduced during a week. One of the reasons for this decrease was the presence of H2O2 in the honeys, and supplementation of catalase significantly improved their survivability in linden honey. The long history of human consumption of fresh honey suggests that viable FLAB cells do not present health concerns.

Screening of the Honey Aroma as a Potential Essence for the Aromachology

The aim of the study was to determine the aroma profiles of four kinds of Slovak honey (sunflower, honeydew, acacia, and linden) by a qualitative and quantitative screening of their volatile compounds and by gas chromatography for the potential use in the aromachology and the business sphere. The results showed that several unique volatiles were identified in one kind of honey, while they were not identified in the remaining ones. The acacia honey had the unique volatile linalool oxide (1.13–3.9%); linden honey had the unique volatiles nerol oxide (0.6–1.6%), ethyl esters (0.41–8.78%), lilac aldehyde D (6.6%), and acetophenone (0.37%). The honeydew honey had the unique volatiles santene (0.28%) and cyclofenchene (0.59–1.39%), whereas 2-bornene (0.43–0.81%) was typical for sunflower honey. While linden honey was characterized by fruity ethyl esters, honeydew honey had more monoterpenoid compounds. In the principal component analysis model, the four kinds of honey could not be differentiated by aroma volatiles. However, it was possible to classify the linden and sunflower honey using the LDA. In conclusion, the current study provided experimental evidence that the marker compounds from different kinds of honey might be promising candidates for production of inhaling aromas.

In Vitro Antibacterial and Antibiofilm Activity of Hungarian Honeys against Respiratory Tract Bacteria.

Honey is a rich source of carbohydrates, while minor compounds such as amino acids and polyphenols contribute to its health-promoting effects. Honey is one of the oldest traditional remedies applied for microbial infections, due to its antibacterial, anti-inflammatory, and antioxidant properties. The aim of this study was to investigate the antibacterial and antibiofilm effects of Hungarian black locust, linden, and sunflower honeys against the most common biofilm-forming respiratory tract pathogens Haemophilus spp., Pseudomonas aeruginosa, and Streptococcus pneumoniae. The unifloral character of all three honey types was confirmed by melissopalynological analysis. The antibacterial activity of each honey sample against each bacterium strain was proven with agar well diffusion assay and thin layer chromatography—direct bioautography. Kinetics and mechanisms of antibacterial action were clarified with time-kill assay and membrane degradation study. The anti-biofilm activity was evidenced using crystal violet assay. In each assay, linden honey was the most effective, followed by sunflower and black locust honey. In addition, each honey sample had greater potential to suppress respiratory tract bacteria, compared to major sugar components. In conclusion, honey in general and linden honey in particular, can have a role in the treatment of respiratory tract infections caused by biofilm-forming bacteria.

Quality Evaluation of Light- and Dark-Colored Hungarian Honeys, Focusing on Botanical Origin, Antioxidant Capacity and Mineral Content.

Melissopalynology, antioxidant capacity and mineral and toxic element contents were analyzed in eight types of Hungarian honeys. Based on color, two groups were distinguished: light honeys comprised acacia, amorpha, phacelia and linden honeys; while dark honeys included sunflower, chestnut, fennel and sage honeys, with 100 to 300 and 700 to 1500 mAU, respectively. The unifloral origin of each sample was supported using pollen analysis. The absorbance of honey correlated positively with antioxidant capacity determined by three different methods (TRC, DPPH, ORAC), and also with mineral content. The exception was the light amber linden honey with significantly higher K content and antiradical activity than other light honeys. The Mn, Zn and Fe contents were the highest in chestnut, sunflower and fennel honeys, respectively. The black meadow sage honey performed best regarding the content of other elements and antioxidant activity. The concentrations of several toxic elements were below the detection limit in the samples, indicating their good quality. The principal component analysis (PCA) revealed correlations between different antioxidant assays and minerals, and furthermore, confirmed the botanical authentication of the honeys based on the studied parameters. To our best knowledge, the present study is the first to provide a complex analysis of quality parameters of eight unifloral Hungarian honeys.

Antioxidant capacity of honey from the urban apiary: a comparison with honey from the rural apiary

Honey is a source of natural antioxidant compounds exerting several health-beneficial effects. Since urban beekeeping is quite common, the fear among potential consumers about the quality and the safety of honey produced exclusively in the cities is observed. However, the antioxidant properties of urban honey have not yet been tested. We described the antioxidant properties of linden honey from urban and rural areas. We analyzed the total phenolic content, DPPH• radical scavenging activity, Trolox equivalent antioxidant activity assay, the protein content, and catalase activity. The analysis showed that all tested parameters were significantly higher in honey from rural areas than in urban samples. The differences in the obtained results are certainly not the effect of the floral composition of honey, but rather due to the location of the honeybee colonies. It seems that the consumption of honey from urban areas for health purposes should be considered.