Eucalyptus Honey Research Articles

Evaluation of Polyphenols, Antioxidant Activity, and Mineral Content in Honey Produced by <i>Apis mellifera</i> L. According to Floral Origin

Background/Objectives: Honey is in high demand because of its nutritional value, therapeutic properties, and sensory characteristics. Honey varieties were evaluated according to their floral origin and physicochemical composition, and total polyphenols, antioxidants, and minerals were analyzed for conformity and preference. Methods: Seven honey samples were analyzed for physicochemical composition using the Official Methods of Analysis method, total polyphenols using the Folin–Ciocalteu method, flavonoids using the ferric trichloride method, antioxidant activity and inhibitory concentration using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, and ferric reducing capacity using the ferric-reducing antioxidant power (FRAP) method. Inductively coupled plasma optical emission spectroscopy was used to determine the mineral composition of the honey varieties. Results: The physicochemical compositions of the honey samples did not show significant differences and complied with national regulations. Total phenolic compound content was 336.9–1064.9 μg EAG/g, whereas flavonoids were between 0–151.9 μg EQ/g, with eucalyptus honey having the highest concentration. The antioxidant capacity measured using DPPH and FRAP was 0.095–0.186 and 0.168–0.654 mM TEAC/g, respectively. Variability was observed in the calcium (161.55 mg/kg in eucalyptus), magnesium (35.20 mg/kg in eucalyptus), potassium (901.17 mg/kg in eucalyptus), and sodium (172.18 mg/kg in pecan aroma) levels. Heavy metals did not exhibit significant values. The correlation between total flavonoid content and antioxidant capacity was weak; a strong correlation was observed between total phenolic compounds and antioxidant activity. Conclusions: The antioxidant activity, bioactive compounds, and minerals in honey vary according to its floral origin, which could be helpful in the pharmaceutical industry and gastronomy.

HS-SPME-GC-MS Analysis of the Volatile Composition of Italian Honey for Its Characterization and Authentication Using the Genetic Algorithm

Honey’s chemical and sensory characteristics depend on several factors, including its botanical and geographic origins. The consumers’ increasing interest in monofloral honey and honey with a clear indication of geographic origin make these types of honey susceptible to fraud. The aim was to propose an original chemometric approach for honey’s botanical and geographic authentication purposes. The volatile fraction of almost 100 Italian honey samples (4 out of which are from Greece) from different regions and botanical origins was characterized using HS-SPME-GC-MS; the obtained data were combined for the first time with a genetic algorithm to provide a model for the simultaneous authentication of the botanical and geographic origins of the honey samples. A total of 212 volatile compounds were tentatively identified; strawberry tree honeys were those with the greatest total content (i.e., 4829.2 ng/g). A greater variability in the VOCs’ content was pointed out for botanical than for geographic origin. The genetic algorithm obtained a 100% correct classification for acacia and eucalyptus honeys, while worst results were achieved for honeydew (75%) and wildflower (60%) honeys; concerning geographic authentication, the best results were for Tuscany (92.7%). The original combination of HS-SPME-GC-MS analysis and a genetic algorithm is therefore proposed as a promising tool for honey authentication purposes.

Identifying Key Markers for Monofloral (Eucalyptus, Rosemary, and Orange Blossom) and Multifloral Honey Differentiation in the Spanish Market by UHPLC-Q-Orbitrap-High-Resolution Mass Spectrometry Fingerprinting and Chemometrics.

Honey differentiation based on the botanical origin is crucial to guarantee product authenticity, especially considering the increasing number of fraud cases. This study assessed the metabolomic differences arising from various botanical origins in honey products sold in Spanish markets, focusing on two goals: (1) discrimination within monofloral samples (eucalyptus, rosemary, and orange blossom honey) and (2) differentiation between multifloral vs. monofloral honey samples. An omics strategy based on ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap-high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS) was applied for the reliable identification of specific honey markers selected by orthogonal partial least squares discriminant analysis (OPLS-DA) (R2Y = 0.929-0.981 and Q2 = 0.868-0.952), followed by the variable importance in projection (VIP) approach. Key amino acid, alkaloid, and trisaccharide markers were identified to distinguish between honey samples. Some Amadori compounds were highlighted as eucalyptus honey markers, suggesting their potential use for honey aging and botanical origin differentiation. L-phenylalanine and raffinose were markers of rosemary honey. Four markers (e.g., trigonelline, L-isoleucine, and N-(1-deoxy-1-fructosyl)isoleucine) were found in higher levels in multifloral samples, indicating a greater availability of amino acids, potentially increasing the Maillard reaction. This research is the first to address the botanical origin's impact on honey by identifying novel markers not previously described.

Effect of Honey Intake on Some Hematological Parameters and Testosterone, Luteinizing Hormone in Sample of Iraqi Men

Introduction and Aim: Natural honey has many biological activities including increase Hematology (Red Blood Cell (RBC), Packed Cell Volume (PCV), Hemoglobin (Hb), Platelets (PLT) and Prothrombin time (PT)) and serum of testosterone and Luteinizing hormone. The aim of these study to know the effect of honey intake on some blood profile and to know the extent of honey impact on testosterone level. Material and Methods: About 20 healthy men were selected aged 45-60 years in Baghdad, given 50 gram Eucalyptus honey daily orally for 30 days and tested blood samples were collecting to measure the previous parameters before and after treatment. Results: The study found that there was a significant increase in all hematology parameters and testosterone hormone after eat the honey.

The Antioxidant Capacity of Monofloral Eucalyptus Flower Honey and Weed Honey Obtained from Jerash and Al-Zarqa Jordanian Governorates

Honey contains natural antioxidants that can help to get rid of free radicals and improve our health. The antioxidant capacity of honey is determined by its chemical makeup. The antioxidant capacity of Monofloral honey, including Eucalyptus flower honey and Weed honey obtained from different Jordanian governorates (Jerash and al-Zarqa) were examined using the phenolic contents (GAE), DPPH free radical scavenging test (%), and Ferric reducing/antioxidant power assay (FRAP). The Folin–Ciocalteu assay was used to assess the total phenol components in terms of the Gallic acid equivalent (GAE) in mg/g. Results showed that the Eucalyptus flower honey, and weeds honey both obtained from Jerash governorate followed by weeds honey obtained from Al-Zarqa governorate have the highest phenolic contents among the honey samples with the values of (10.6734 + 0.006) mg/g, (10.43889 + 0.012) mg/g and (10.1345+ 0.004) mg/g; respectively. The DPPH scavenging assay as compared to BHT scavenging (reference control) 59.61%, has demonstrated that the eucalyptus flower honey obtained from Al-Zarqa governorate and weeds honey obtained from Jerash governorate have exhibited the highest DPPH scavenging among honey samples with the values (12.8734+ 0.008)% and (11.5635+ 0.006)% respectively. Moreover, the reducing power tests of the reference compound ascorbic acid (0.751 mg/ml) have demonstrated that the weeds honey and eucalyptus honey both obtained from Jerash governorate have exhibited the highest reducing power with values of (15.8857+ 0.002) mg/ml and (16.8787+ 0.004) mg/ml respectively. It is important to note that honey has varying levels of antioxidant activity depending on its source and content.&nbsp

Multivariate Statistical Approach for the Discrimination of Honey Samples from Galicia (NW Spain) Using Physicochemical and Pollen Parameters.

Raw honey is a food with a close relation to the territory in which it is produced because of factors such as soil conditions, weather patterns, and plant communities living in the area together. Furthermore, beekeeping management affects the properties of honey. Protected Geographical Indication Miel de Galicia protects the honey produced in Galicia (Northwest Spain). Various types of honeys (362 samples) from this geographical area were analyzed using chemometric techniques. Principal component analysis was favorable to analyzing the physicochemical and pollen variables with the greatest weight in the differentiation of honey. The linear discriminant analysis correctly classified 89.8% of the samples according to the botanical origin using main pollen spectra and physicochemical attributes (moisture, pH, electrical conductivity, diastase content, phenols, flavonoids, and color). Regarding unifloral honey, blackberry, eucalyptus, and heather honeys were correctly grouped, while five chestnut honeys and fourteen samples of honeydew honeys were misclassified. The chestnut and honeydew honeys have similar physicochemical properties and frequently similar pollen spectra profiles complicating the differentiation. Experimental evidence suggests the potential of multivariate statistics in the characterization of honey of the same geographical origin. Therefore, the classification results were good, with electrical conductivity, total phenol content, total flavonoid content and dominant pollens Eucalyptus, Erica, Rubus and Castanea sativa as the variables of higher importance in the differentiation of botanical origin of honeys.

Etude physicochimique de miels des régions du Sud du Sénégal (la Casamance)

Honey is a highly complex biological compound that sits somewhere between the animal and plant worlds. With its wide diversity, honey offers a multitude of properties, both nutritional and therapeutic. In order to determine its physicochemical characteristics, five types of samples were collected from the southern region of Senegal. These are Eucalyptus honey, Diallium honey, Mangrove honey, Anacardia honey and Daniellia honey. These honeys are analyzed for pH, water content, electrical conductivity, ash content, acidity, hydroxymethylfurfural content and reducing sugars. The results of the physicochemical analyzes informed us that the samples have on average an acidic pH of 3.78 ± 0.29, a water content of 16.34 ± 0.81%, an electrical conductivity of 0.36 ± 0.07 ms/cm, an ash content of 0.29 ± 0.15%, a free acidity of 20.77 ± 4.72 meq/kg, an HMF content of 12.97 ± 6.01 mg/kg and a content in reducing sugars of 52.40 ± 3.33%. The results showed that there were differences from one honey sample to another, and that they all met international standards. The physicochemical parameters studied are the most frequently used as indicators of honey quality and stability, and have a major influence on its organoleptic properties.

Qualitative characteristics of four Sicilian monofloral honeys from Apis mellifera ssp. sicula

Four monofloral honeys, obtained from the Sicilian black bee by foraging on thistle, sulla, chestnut and eucalyptus, were studied. Results showed that the phenolic composition of chestnut honey was the highest (316 mg gallic acid equivalent GAE/kg), while that of sulla honey was the lowest (122 mg GAE/kg). Data confirmed a correlation between the total phenol content and colour intensity in chestnut honey, which was the darkest of the four samples. Sulla honey showed the highest antioxidant activity, while eucalyptus honey had the highest mineral content (K, Ca, Mg, and Na). Thistle honey showed the most intense floral and fruity aromas, as well as an intense -yellow colour. Principal component analysis showed the potential to discriminate different honeys in three different quadrants.

Polysucrose hydrogel loaded with natural molecules/extracts for multiphase-directed sustainable wound healing.

Natural molecules/extracts have numerous beneficial effects on wound healing processes which are challenged by appropriate use and non-toxic dosage. Polysucrose-based (PSucMA) hydrogels have been synthesized with in situ loading of one or more natural molecules/extracts namely Manuka honey (MH), Eucalyptus honey (EH1, EH2), Ginkgo biloba (GK), thymol (THY) and metformin (MET). EH1 presented low amounts of hydroxymethylfurfural and methylglyoxal compared to MH indicating that EH1 was not temperature-abused. It also showed high diastase activity and conductivity. GK was added to PSucMA solution along with other additives including MH, EH1 and MET and crosslinked to form dual loaded hydrogels. The in vitro release profiles of EH1, MH, GK and THY from the hydrogels followed the exponential Korsmeyer-Peppas equation, with a release exponent value of less than 0.5 indicating a quasi-Fickian diffusion mechanism. The IC50 values of these natural products using L929 fibroblasts and RAW 264.7 macrophages indicated that EH1, MH and GK were cytocompatible at relatively high concentrations compared to MET, THY and curcumin used as a control. MH and EH1 induced high IL6 concentration compared to GK. In vitro studies were modelled to mimic the overlapping wound healing phases using human dermal fibroblasts (HDFs), macrophages and human umbilical endothelial cells (HUVECs) in dual culture. HDFs showed a highly interconnected cellular network on GK loaded scaffolds. EH1 loaded scaffolds were seen to induce formation of spheroids which increased in number and size in co-culture studies. The SEM images of HDF/HUVEC seeded GK, GKMH and GKEH1 loaded hydrogels indicated formation of vacuoles and lumen structures. These results indicated that a combination of GK and EH1 in the hydrogel scaffold would accelerate tissue regeneration by acting on the four overlapping phases of wound healing.

Secretion of IL-6 by fibroblasts exposed to Australian honeys involves lipopolysaccharide and is independent of floral source

Honey stimulates cellular secretion of cytokines, which has been attributed to activation of lipopolysaccharide (LPS)-dependent and LPS-independent pathways. The objective of this study was to identify whether LPS is present in Australian honey samples at levels that can stimulate interleukin-6 (IL-6) secretion by fibroblasts and whether it can transduce cell signalling by activating toll-like receptor 4 (TLR4). IL-6 was measured in culture media of fibroblasts exposed to honey for 24 h. LPS was detected in a 0.125 mg/mL solution of grey ironbark honey (0.61 ± 0.05 ng/g honey). TLR4 signalling was observed in RAW264.7 macrophages that were exposed to honey and this was prevented by preincubating the honey with the LPS-neutralising agent, polymyxin B. Australian Eucalyptus, Leptospermum and Cyathode honeys stimulated IL-6 secretion in cultured human dermal fibroblasts. To examine whether the response was dependent on floral source, fibroblasts were exposed to four different samples of grey ironbark honey obtained from Queensland and New South Wales, Australia. The magnitude of the cytokine response to these honeys was highly varied. We conclude that Australian honeys contain endotoxin at levels that can stimulate IL-6 secretion by fibroblasts and that signalling in macrophages involves TLR4 activation. The IL-6 secretory response was independent of floral source.

Italian Consumer Preferences for Eucalyptus Honey: An Exploratory Study

The growing concern for environmental issues has underlined the need to promote sustainable consumption and production. Taking into consideration the three pillars of sustainability, honey should be seen as an important food from a sustainability perspective. Among honey varieties, the eucalyptus one is becoming increasingly popular with people for its aroma and the plant’s therapeutic properties. However, the beekeeping sector in Italy does not yet have sufficient knowledge and understanding of consumer needs with a view to increasing earnings. This paper aimed to analyze the drivers that make people pick eucalyptus honey and tries to investigate which extrinsic and intrinsic quality attributes affect consumer behavior. Data came from an online survey of 403 Italian honey consumers. An ordered Probit model was applied. The results show that consumers consider the taste, viscosity, therapeutic properties, brand reputation, variety, geographical indication, Italian origin, and organic certification of honey as the most important factors that drive the consumption of eucalyptus honey. The findings of the study should help the beekeepers and provide them with the right tools of communication, such as quality or sustainability labeling, thereby increasing their competitiveness.

Quality assessment of Portuguese monofloral honeys. Physicochemical parameters as tools in botanical source differentiation

The quality evaluation and physicochemical parameters assessment of Portuguese monofloral honeys were performed. Fifty-one monofloral honeys were collected from several regions from mainland Portugal, and from the Azores islands, producer labelled as carob tree (n = 5), chestnut (n = 2), eucalyptus (n = 5), bell heather (n = 6), incense (n = 4), lavender (n = 8), orange (n = 9), rape (n = 2), raspberry (n = 2), rosemary (n = 1), sunflower (n = 3), and strawberry tree (n = 4). Pollen analysis and microbiological safety were evaluated, and the parameters such as colour index, moisture content, electrical conductivity, hydroxymethylfurfural, pH, free and total acidity, diastase activity, proline, and sugar profile were assessed for physicochemical characterization, in all 51 monofloral honeys. After melissopalynological examination, the honeys were either confirmed as monofloral, or classified as multifloral with predominance of a specific pollen type or multifloral. Microbiological analysis showed that honeys were safe for human consumption. Pairwise comparisons of physicochemical parameters, using only honey types with n ≥ 3, revealed significant differences between honey types. Despite some homogeneity in sugar profile among honeys, eucalyptus honey was significantly different in glucose, maltose and maltulose content compared to incense, orange and sunflower honeys, and also exhibited a higher isomaltose amount compared to all analyzed honeys. Electrical conductivity, colour index, free and total acidity, and diastase activity showed significant differences between the analyzed honeys, indicating that these parameters may provide an additional tool in monofloral honey identification.

Caracterização de méis de duas paisagens da região nordeste do Uruguai

The world honey market values ​​organic and natural honeys. Forest activity in the northeast of Uruguay, free of agricultural activities and with the presence of a protected area, is an opportunity for local beekeepers and transhumant people. The characterization of these honeys through melissopalynology and physical-chemical parameters could generate new valorization strategies. The objective of this study was to characterize honeys (n=27) from the protected area and from afforestation with Eucalyptus grandis under two production systems (transhumance and non-transhumance beekeepers). Botanical composition was analyzed by palynology, mineral profile, moisture, conductivity, pH, color (CIEL*a*b*), sugar profile and presence of glyphosate. The palynological analysis determined two types of honeys (monofloral from Eucalyptus sp. in the forestation and honeydew honeys with the presence of diverse pollens from native species in the protected area. No significant differences (p<0.05) were found between the honeys from eucalyptus for both beekeeping production systems in all the parameters evaluated. The honeydew honeys have an unknown origin and were statistically different from the previous ones. The average values ​​of pH and conductivity for these honeys were 6.37 ± 0.14 and 1113 ± 25.6 µS/cm respectively. The concentration of minerals K (2536.1 ± 382.1 mg/kg honey) and Fe (4.15 ± 0.27 mg/kg honey) was higher than those found in eucalyptus honey. The percentages of Isomaltulose (1.18 ± 0.62) and Trehalose (0.23 ± 0.05) sugars were higher in the honeys from the protected area while Maltose (0.46 ± 0.07) was lower. Glyphosate residues were not detected in all the samples analyzed. Should insist on good management practices carried out by beekeepers when they arrive from agricultural areas (transhumance beekeepers). Research should continue to determine the origin of the myelates in the protected area. Although the volumes produced are smaller, their valuation could increase due to the originality of these honeys. The northeast region of Uruguay has the potential to produce quality honey properly identified by geographic and botanical origin.

Antifungal, antibiofilm and anti-resistance activities of Brazilian monofloral honeys against Candida spp.

Candida is a fungus commonly involved in diseases of the skin and mucous membranes and has a high resistance to antifungal drugs. Moreover, there are few therapeutic options to treat these infections. Honey is a popular product that is easily accessible and has a diverse chemical composition, such as phenolic compounds that can have an antimicrobial effect in various metabolic pathways. Therefore, in this study, we aimed to characterize the antifungal activity of tree popular Brazilians honey against Candida species. Aroeira, Eucalyptus and Assa-Peixe honey was characterized by total phenolics and its antifungal activity on Candida species was tested by the microdilution method, antibiofilm activity, yeast to hypha (Y–H) transition, combination assays, multistage resistance study, and antibi-scanning electron microscopy of the fungi. Aroeira honey showh potent antifungal activity in vitro against planktonic cells of C. albicans (MIC 20–30% w/v) and non-albicans (MIC 30–40% w/v) and also breaks down mature biofilms formed by these yeasts at 40% w/v. Urethral catheters sensitized with 30% Aroeira honey reduced adhesion and biofilm formation by C. albicans. Aroeira honey did not induce resistance in C. albicans during the 21-day exposure. Its ability to alter fungal membrane structure contributes to the synergistic effects of Aroeira honey with commercial antifungal agents (miconazole, ketoconazole, itraconazole). Aroeira honey inhibits yeast-to-alpha transition in C. albicans, and its prior exposure for 1 h reverses the azole resistance profile of a highly resistant strain of C. albicans. Taken together, these results indicate that Aroeira honey is a promising therapeutic agent against superficial candidiasis.

Multi-Elemental Analysis as a Tool to Ascertain the Safety and the Origin of Beehive Products: Development, Validation, and Application of an ICP-MS Method on Four Unifloral Honeys Produced in Sardinia, Italy.

Despite unifloral honeys from Sardinia, Italy, being appreciated worldwide for their peculiar organoleptic features, their elemental signature has only partly been investigated. Hence, the principal aim of this study was to measure the concentration of trace and toxic elements (i.e., Ag, As, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Te, Tl, V, and Zn) in four unifloral honeys produced in Sardinia. For this purpose, an original ICP-MS method was developed, fully validated, and applied on unifloral honeys from asphodel, eucalyptus, strawberry tree, and thistle. Particular attention was paid to the method’s development: factorial design was applied for the optimization of the acid microwave digestion, whereas the instrumental parameters were tuned to minimize the polyatomic interferences. Most of the analytes’ concentration ranged between the relevant LoDs and few mg kg−1, while toxic elements were present in negligible amounts. The elemental signatures of asphodel and thistle honeys were measured for the first time, whereas those of eucalyptus and strawberry tree honeys suggested a geographical differentiation if compared with the literature. Chemometric analysis allowed for the botanical discrimination of honeys through their elemental signature, whereas linear discriminant analysis provided an accuracy level of 87.1%.

Tunisian consumer preferences for local forest honey attributes: A market segmentation analysis

Aim of study: This study focuses on the segmentation of local forest honey market based on consumer preferences for its origin and other sensory attributes. Area of study: Tunisia Material and methods: The empirical analysis relies on a face-to-face questionnaire survey of 200 respondents, conducted in 2019 among Tunisian consumers. A cluster analysis was used to identify the market segments and multinomial logit analysis was used to determine segment membership characteristics. Main results: Three distinct market segments were identified. The first segment of consumers (44% of the sample) prefer eucalyptus and multifloral honey from the Northwest origin; the second segment (39%) is composed of consumers that tend to buy honey mainly produced in the eastern region of the country; in the third (17%), consumers prefer thyme-rosemary' honey. Research highlights: Consumer preferences for local forest honey mainly depend on its geographical origin, flower type, flavor and color. Findings suggest that gender, income, and grocery shopping task are the main determinants of the importance of these attributes.

Finding the optimum treatment procedure to delay honey crystallization without reducing its quality

The current study investigated the effect of different thermal and non-thermal procedures for the estimation of the optimum conditions of treatment of different honey types (erica, cotton, thyme, eucalyptus and pine honey) to avoid or delay crystallization without losing the nutritional benefits of honey. Different physicochemical parameters, such as pollen analysis, hydroxymethylfurfural (HMF), diastase activity, acidity, and total phenolic compounds were used as quality indicators. The different treatment procedures were evaluated in different honey types and in different time periods. It was proved that to achieve a non-crystallised product that lasts over a year, samples must be heated at 72 oC or stored at −18 °C. However, only by storing samples at −18 °C kept the nutritional benefits of honey and provide similar results with the fresh unheated samples. All procedures were examined in a long-term period (one year) in order to have a complete and accurate result.

Anti-inflammatory activities of Italian Chestnut and Eucalyptus honeys on murine RAW 264.7 macrophages

The aim of this study was to evaluate for the first time the anti-inflammatory effects of chestnut (Castanea sativa) and Eucalyptus (Eucalyptus occidentalis) honeys collected in Italy on murine RAW 264.7 macrophages stressed with the bacterial endotoxin lipopolysaccharide (LPS). Pre-treatment with the two honeys markedly decreased apoptosis and stimulated wound healing in macrophages stressed with LPS, where they also reduced the intracellular levels of ROS and nitrite. Additionally, treatment with LPS decreased the levels of glutathione and suppressed the antioxidant enzyme activities, which were significantly (p < 0.05) increased in the presence of the two honeys, through the modulation of Nrf2 expression; in LPS-stressed macrophages, Chestnut or Eucalyptus honeys protected against inflammation by regulating the main inflammatory biomarkers, including TNF-α, IL-10 and iNOS, through the decrease of NF-кB expression. Finally, they improved mitochondrial respiration and the main related parameters.

Chemometric evaluation of antioxidant activity and α-amylase inhibition of selected monofloral honeys from Algeria

This study was conducted on 34 honey samples produced in Algeria from different botanical and geographical origins. The main objective was to compare some biological properties like the antioxidant capacity and the α-amylase inhibition of different honey types and their relationship with physicochemical properties. The botanical origin of the samples was confirmed by pollen analysis. The samples were collected directly from beekeepers during the 2018 and 2019 harvest seasons and were analyzed for physicochemical parameters, color, total phenolic and flavonoid content, antioxidant capacities (DPPH, ABTS .+), and α-amylase inhibition as a preliminary study in order to estimate the antidiabetic activity. Some of the most marketed honey types as polyfloral or Eucalyptus honey were included, but highlights the information obtained for poorly studied honey types as Lenj honey (Arbutus), Mimouza honey (Acacia), Retem honey (Retama sphaerocarpa), El Kebbar honey (Capparis), or unknown honey types as those from El Sorr (Atractytlis serratuloides), El Harra (Eruca sativa) and El Merkh (Genista saharae). According to the results, the darker samples were those of Retama, Eucalyptus, Acacia, Arbutus, and polyfloral honey types and had higher electrical conductivity, higher phenolic, and flavonoid content together with an important antioxidant activity compared to Genista, Atractylis, and Eruca honey types. Arbutus honey had the highest α-amylase inhibition but Eruca sativa and Retama samples can be distinguished also by this property.

Effect of thermal liquefaction on quality, chemical composition and antibiofilm activity against multiresistant human pathogens of crystallized eucalyptus honey

Thermal liquefaction is a conventional method used by beekeepers to liquefy crystallized honey. However, an abusive use of heat may affect its quality, chemical composition and bioactivity. The purpose of this study was to investigate the effect of thermal liquefaction on the quality, chemical composition and antibiofilm properties of eucalyptus honey. Thermal liquefaction (at 45 and 60 °C) did not affect the honey’s quality; however, a significant reduction in the reducing capacity, total phenolic content and hydrogen peroxide content was observed. At 60 °C, a significant reduction in the honey’s ability to inhibit biofilm formation was observed in Pseudomonas aeruginosa, as well as a reduction in its ability to remove preformed biofilms in both Staphylococcus aureus and Pseudomonas aeruginosa. Structural changes in biofilm architecture caused by honey were not affected by thermal treatment. Therefore, we recommend liquefaction at 45 °C as the most convenient for honey liquefaction without affecting its characteristics.