Search Results (93)

Second-harmonic generation microscopy is applied to mesquite honey samples with different fructose adulteration concentrations. As a proof of principle, mesquite honey is selected for this test, as it has a monofloral and spreadable-like-butter consistency, besides its economic relevance in the central region of Mexico. Second-harmonic generation microscopy is an optical method that images microstructures, such as sugar crystals in bee honey, without the interference of the liquid phase. Each recorded image is spectrally registered using the photomultiplier detector of the microscope, resulting in several gray-level histograms that are numerically analyzed using signal and image processing techniques. Several samples are prepared, adulterated, and analyzed for this purpose. The inspection requires only a microscopic amount of honey, making it a suitable technique for rare and exotic honey samples that are harvested in limited quantities. The analysis of the experimental results reveals that the second-harmonic generation microscopy signal is sensitive to liquid fructose adulteration in honey, with its signal decreasing as the amount of added fructose increases. Full article

Honey quality and authenticity are influenced by floral origin, processing, and storage, with implications for composition and sensory appeal. This study offers a comparative assessment of eight monofloral honey samples, representing five botanical varieties: acacia, linden, rapeseed, lavender, and thyme. For acacia, linden, and rapeseed, both producer-sourced and commercial honeys were analyzed, while lavender and thyme samples were available only from local beekeepers. The botanical origin of each sample was confirmed using morphological markers of pollen grains. Physicochemical characterization included acidity, pH, moisture content, refractive index, hydroxymethyl furfural (HMF), proline concentration, and carbohydrate profiling by HPLC-RID. Acacia honey exhibited the lowest acidity and HMF levels, alongside the highest fructose/glucose (F/G) ratios, indicating superior freshness, lower crystallization risk, and a sweeter flavor profile. In contrast, rapeseed honey showed elevated glucose levels and the lowest F/G ratio, confirming its tendency to crystallize rapidly. All samples recorded proline concentrations well above the quality threshold (180 mg/kg), supporting their authenticity and proper maturation. The estimated glycemic index (eGI) varied between 43.91 and 62.68 and was strongly inversely correlated with the F/G ratio (r = −0.98, p < 0.001). Sensory evaluation highlighted acacia honey from producers as the most appreciated across visual, tactile, and flavor attributes. Correlation analyses further revealed consistent links between sugar composition and both physical and sensory properties. Overall, the findings reinforce the value of integrated analytical and sensory profiling in assessing honey quality and authenticity. Full article

The increasing scarcity of traditional nectar sources due to climate change has led beekeepers to explore alternative floral sources. This study investigates the volatile profile, sensory characteristics, and consumer acceptability of monofloral honey derived from Capparis spinosa L., a drought-resistant Mediterranean plant. Honey samples produced by Apis mellifera ssp. sicula on Aeolian Islands (Sicily, Italy) were analyzed. Volatile organic compounds (VOCs) were extracted using headspace solid–phase microextraction (HS-SPME) and identified by gas chromatography–mass spectrometry (GC–MS), revealing 59 compounds, with dimethyl sulfide being the predominant one. Sensory evaluation using quantitative descriptive analysis (QDA) and Time Intensity (TI) analysis identified distinctive descriptors such as sweet-caramel, cabbage/cauliflower, and pungent notes. Statistical analyses confirmed correlations between specific VOCs and sensory perceptions. A consumer acceptability test involving 80 participants showed lower preference scores for caper honey in terms of aroma and overall acceptability compared to commercial multifloral honey, with differences observed across age groups. The unique aromatic profile and consumer feedback suggest that caper honey has strong potential as a niche, high-quality product, particularly within the context of climate-resilient beekeeping, offering valuable opportunities for innovation and diversification in sustainable apiculture. Full article

The quality and stability of honeys are strongly influenced by their chemical composition and physicochemical properties, which vary with botanical origin. This study examined the physicochemical and compositional properties of cotton, heather, orange, thyme, Christ’s thorn, and chestnut monofloral honey samples, as well as the kinetics of the creaming–crystallization process by monitoring rheological and color parameters. All samples had moisture content lower than the legislation limit (<20%) and a_w ≤ 0.60. Chestnut and heather honeys exhibited the highest electrical conductivity and darkest color. Fructose was the predominant sugar in all samples, with thyme having the highest content. Viscosity decreased exponentially with increasing moisture, with thyme honey being the most viscous. Principal component analysis showed distinct clustering of samples based on their compositional–physicochemical characteristics. Calorimetry revealed the water’s plasticization effect on honey solids, lowering their glass transition temperature, with the data fitting well to the Gordon–Taylor model. Rheometry indicated a Newtonian-like behavior for liquid honeys, evolving towards a pseudoplastic response upon creaming–crystallization. Cotton honey crystallized rapidly, thyme honey showed moderate crystallization propensity, while samples of heather honey gave a diverse response depending on composition. Overall, high glucose content and/or low fructose/glucose ratio promoted honey crystallization, leading to the formation of highly viscous-creamed honey preparations. Full article

Strawberry tree honey (Arbutus unedo L.) is a rare monofloral honey type with unique characteristics, mainly produced in the Mediterranean region. Despite its distinct qualities, limited research on its physicochemical and biological properties, coupled with the absence of specific legislative standards, hinder its market potential. For this reason, in the present study, we analyzed strawberry tree honey samples collected from beekeepers in Western Greece, focusing on physicochemical properties (moisture, electrical conductivity, HMF, diastase activity, color, pH, acidity), total phenolic content, antioxidant activity, carbohydrate composition, and phenolic compounds profile. The results revealed high moisture content (19.2 ± 1.9%) and electrical conductivity (0.784 ± 0.132 mS cm⁻¹), low diastase activity (9.6 ± 3.8 DN), and a strong crystallization tendency (1.01). Additionally, the honey exhibited elevated levels of total phenolic content (1169.9 ± 323.8 mg GAE kg⁻¹ honey) and total antioxidant activity (10.98 ± 2.42 mmol Fe²⁺ kg⁻¹ honey), compared to other blossom honeys, with homogentisic acid emerging as the dominant phenolic compound. These findings highlight the potential of strawberry tree honey as a high-value product, contributing to its enhanced market promotion. Full article

Honey is a multifaceted substance whose composition is intricately affected by various biotic and abiotic elements generated in the bee colony’s surroundings, including botanical and geographical origins, climatic conditions, soil characteristics, and beekeeping techniques. Monofloral honeys are identified by pollen analysis and are derived from the nectar of a predominant plant species, exhibiting rich sensory and nutritional profiles, making them food matrices with unique characteristics and excellent qualities. To explore the monofloral honey potential harvested in different regions of Portugal, a comprehensive study was conducted including the determination of phenolic composition and the assessment of biological activities. In addition to this evaluation, the inter simple sequence repeat (ISSR) was used to help differentiate honeys by botanical origin. The phenolic content and the antioxidant capacity were evaluated by spectrophotometric methods, observing, in general, differences between monofloral honeys. The honey from Citrus sinensis (Silves) exhibited the lowest phenolic content, including total phenols, ortho-diphenols, and flavonoids, whereas honeydew (Vinhais) showed the highest values. Regarding the antioxidant capacity, honey from Lavandula stoechas (Almodôvar) presented the lowest values, while honeydew (Vinhais) displayed the highest values for both DPPH and FRAP assays. In relation to the ABTS assay, the honey from Metrosideros excelsa (Aveiro) exhibited the lowest values, whereas the honey from Eucalyptus spp. (Arouca) showed the highest. The ISSR marker analysis allows the distribution of the samples based on the honey’s botanical origin, suggesting its potential role in honey authentication. Full article

Honey has long been valued for its medicinal properties, yet the therapeutic potential of Irish monofloral honey remains largely unexplored. This study investigates the antioxidant and immunomodulatory effects of Irish ivy (Hedera helix) and heather (Calluna vulgaris) honey samples on PMA-differentiated THP-1 macrophages, a well-characterised immune model. Antioxidant capacity was assessed through free radical scavenging assays, DPPH and ORAC, while qPCR analysis examined the key inflammatory markers. Both the heather and ivy honey varieties demonstrated antioxidant activity, with heather honey exhibiting the highest total phenolic content (TPC), and ivy honey stimulating Nrf2 activation. Manuka honey showed the strongest radical scavenging capacity, as reflected in its higher ORAC and DPPH values. These findings suggest that the different honey varieties may exert antioxidant effects through distinct mechanisms. Exposure to honey reduced oxidative stress and upregulated the expression of a key antioxidant transcription regulator (Nrf2) and an associated downstream antioxidant defence enzyme, superoxide dismutase (SOD). Additionally, both the honey types exhibited immunomodulatory effects, upregulating pro-inflammatory cytokines, such as TNF-α and IL-1β, while increasing the expression of the anti-inflammatory cytokine IL-10. These findings suggest potential bioactive properties that warrant further investigation. Given the growing interest in alternative treatments for inflammation-related conditions, further research is warranted to determine whether the observed in vitro effects translate into clinically relevant outcomes. This study expands the current understanding of Irish monofloral honey, reinforcing its potential as a functional bioactive compound with relevance in antioxidant therapies, immune modulation, and wound healing. Full article

Honeybees are of economic importance not only for honey production, but also for crop pollination, which amounts to USD 20 billion per year in the United States. However, the number of honeybee colonies has declined more than 40% during the last few decades. Although this decline is attributed to a combination of factors (parasites, diseases, pesticides, and nutrition), unlike other factors, the effect of nutrition on honeybee health is not well documented. In this study, we assessed the differential expression of seven genes linked to honeybee health under three different diets. These included immune function genes [Cactus, immune deficiency (IMD), Spaetzle)], genes involved in nutrition, cellular defense, longevity, and behavior (Vitellogenin, Malvolio), a gene involved in energy metabolism (Maltase), and a gene associated with locomotory behavior (Single-minded). The diets included (a) commercial pollen patties and sugar syrup, (b) monofloral (anise hyssop), and (c) polyfloral (marigold, anise hyssop, sweet alyssum, and basil). Over the 2.7-month experimental periods, adult bees in controls fed pollen patties and sugar syrup showed upregulated Cactus (involved in Toll pathway) and IMD (signaling pathway controls antibacterial defense) expression, while their counterparts fed monofloral and polyfloral diets downregulated the expression of these genes. Unlike Cactus and IMD, the gene expression profile of Spaetzle (involved in Toll pathway) did not differ across treatments during the experimental period except that it was significantly downregulated on day 63 and day 84 in bees fed polyfloral diets. The Vitellogenin gene indicated that monofloral and polyfloral diets significantly upregulated this gene and enhanced lifespan, foraging behavior, and immunity in adult bees fed with monofloral diets. The expression of Malvolio (involved in sucrose responsiveness and foraging behavior) was upregulated when food reserves (pollen and nectar) were limited in adult bees fed polyfloral diets. Adult bees fed with monofloral diets significantly upregulated the expression of Maltase (involved in energy metabolisms) compared to their counterparts in control diets to the end of the experimental period. Single-Minded Homolog 2 (involved in locomotory behavior) was also upregulated in adult bees fed pollen patties and sugar syrup compared to their counterparts fed monofloral and polyfloral diets. Thus, the food source significantly affected honeybee health and triggered an up- and downregulation of these genes, which correlated with the health and activities of the honeybee colonies. Overall, we found that the companion crops (monofloral and polyfloral) provided higher nutritional benefits to enhance honeybee health than the pollen patty and sugar syrup used currently by beekeepers. Furthermore, while it has been reported that bees require pollen from diverse sources to maintain a healthy physiology and hive, our data on nuclear colonies indicated that a single-species diet (such as anise hyssop) is nutritionally adequate and better or comparable to polyfloral diets. To the best of our knowledge, this is the first report indicating better nutritional benefits from monofloral diets (anise hyssop) over polyfloral diets for honeybee colonies (nucs) in semi-large-scale experimental runs. Thus, we recommend that the landscape of any apiary include highly nutritious food sources, such as anise hyssop, throughout the season to enhance honeybee health. Full article

This study aimed to characterize the metabolomic profile of monofloral honey from Eucryphia cordifolia (ulmo) and evaluate the potential transfer of bioactive compounds from the plant parts, including the leaves and flowers, to the honey. Using UHPLC/Q-TOF-MS analysis, various flavonoids and phenolic acids were identified and quantified in extracts from the leaves, flowers, and honey from E. cordifolia. Given their rich polyphenolic composition, E. cordifolia leaves were included in this study to assess their potential contribution to the antioxidant properties and chemical markers of ulmo honey. Additionally, the polyphenolic compounds in honey samples were quantified. Chromatographic analysis via UHPLC-MS/MS revealed that ulmo honey contains phenolic acids such as gallic, syringic, ferulic, chlorogenic, caffeic, and coumaric acid, as well as flavonoids including pinocembrin, quercetin, luteolin, kaempferol, epicatechin, apigenin, and isorhamnetin. The results indicate that pinocembrin and gallic acid are the main chemical markers of ulmo honey, while isorhamnetin could complement its characterization as a complementary marker. UHPLC/Q-TOF-MS analysis was also utilized to compare the compounds present in the honey with those found in the plant parts (leaves and flowers), respectively. A total of 10 shared compounds were identified, 9 of which were preliminarily identified, while 1 remains unknown. Notably, dihydroquercetin 3-O-rhamnoside, quercetin 3-O-rhamnoside, cyanidin 3-(p-coumaroyl)-glucoside, and eupatorin were detected in ulmo honey for the first time. Along with gallic acid, pinocembrin, and isorhamnetin, these compounds could contribute to a characteristic fingerprint for identifying the botanical origin of the honey. Overall, these findings provide valuable insights into the chemical composition of ulmo honey and its potential application as a functional product with antioxidant properties. Full article

The increasing prevalence of monocultures has reduced floral diversity, diminishing pollen diet variety for bees. This study examines the impact of monofloral pollen diets (hazel, rapeseed, pine, buckwheat, Phacelia, goldenrod) on the antioxidant enzyme activities in the fat body from tergite 3, tergite 5, sternite, and hemolymph of honey bees. We show that pollen from plants such as rapeseed, Phacelia, buckwheat, and goldenrod (rich in phenolic compounds and flavonoids) increases the activities of SOD, CAT, GST, and GPx in the fat body and hemolymph compared to the control group. Although it is commonly known that a monodiet is one of the stress factors for bees, the increase in the activities of these enzymes in the hemolymph and fat body of workers fed with pollen candy compared to those fed only sugar candy has a positive (although inconclusive) effect. These activities in the hemolymph and fat body of bees fed with pollen from anemophilous plants are usually lower compared to those in bees fed with candy containing 10% pollen from rapeseed, Phacelia, buckwheat, or goldenrod. Further research is needed to fully understand the complex interactions among monofloral pollen diets, antioxidant enzyme activities, and the overall physiology of honey bees. Full article

The present study aims to evaluate and compare some of the main indicators characterizing Bulgarian linden honey depending on the geographical origin. A total of 18 samples were collected from the six regions of Bulgaria, with 3 samples from each region taken from different producers during the 2023 harvest. The physicochemical indicators: hydroxymethylfurfural content, diastase activity, pH, color, water content and electrical conductivity, as well as organoleptic and pollen characteristics, were analyzed. Antioxidant activity was also investigated by several methods: total phenolic content (TPC), phenolic compounds by the Glories method, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical activity, CUPRAC (Cupric Reducing Antioxidant Capacity), iron-reducing antioxidant capacity (FRAP) assay, and radical scavenging capacity in terms of ABTS•+, ORAC (oxygen radical antioxidant capacity). Differences were found depending on the region. All the studied honeys from the Northern Central Region contained higher Tilia sp. pollen. In the Southwestern Region, Tilia sp. pollen was not detected in any of the honey samples. The highest sensory score was awarded to linden honey from the Northern Central Region. An overall assessment ranks linden honey from the Northern Central region, the richest in linden forests, as the highest quality among the six studied regions. Another key finding was that 39% of linden honey labeled or declared as monofloral linden honey on the Bulgarian market does not meet the established criteria for monofloral honey. Full article

Any change in the composition or physicochemical parameters of honey outside the standardized intervals may be deemed fraud, irrespective of direct introduction of certain substances or feeding honeybees with syrups. Simple and rapid tools along with more sophisticated ones are required to monitor fraudulent practices in the honey trade. In this work, UV–Vis spectroscopy was used to identify and quantify six Romanian honey types (five monofloral and one polyfloral) mixed with commercially available corn syrup, corn syrup with plant extracts, inverted syrup, and fruit syrup at different concentrations (5%, 10%, 20%, 30%, 40%, and 50%). Relevant spectral features were used to develop a neural model, which was able to pinpoint adulteration, regardless of the honey and adulterant type. The proposed model was able to detect adulteration levels higher than 10%, thereby serving as a cost-effective and reliable tool to monitor honey quality. Full article

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. Full article

Although the EU is a major producer of honey, commercial production is often insufficient to meet market demand and, as a result, honey is often imported into the EU from extra-EU countries that lack regulatory standards for food safety and quality. Since honey is a matrix highly susceptible to contamination, monitoring the quality and safety of extra-EU honey is of significant importance to show potential safety gaps. Hence, aim of the study was to monitor the mineral profile of monofloral and multifloral honeys from different regions of North (provinces of Tiaret and Laghouat) and South Algeria (province of Tindouf). In almost all the samples, Mg, Fe, Zn, Cd and Pb were found at levels exceeding the limits set for honey by the Codex Alimentarius and European Regulation 915/2023. In addition, a PCA analysis pointed out that the analysis of the element profile was useful to discriminate Algerian honeys more on the basis of geographical than botanical origin. The dietary exposure assessment indicates that the investigated honeys can be safely consumed in quantities comparable to those considered in Europe (1.8 g/day) and North Africa (0.3 g/day). Hopefully, data from this study may solicit the Algerian government to set regulatory limits on inorganic elements in honey and align with other international standards, to create a harmonized network able to improve the safety of this food. Full article

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. Full article