Characterisation of Serbian unifloral honeys according to their physicochemical parameters

Assessing the Impact of Botanical Origins, Harvest Years, and Geographical Variability on the Physicochemical Quality of Serbian Honey

This study summarized the physicochemical analysis of 609 honey samples originating from the Republic of Serbia. Variations among honey samples from different botanical origins, regions of collections, and harvest years were exposed to descriptive statistics and correlation analysis that differentiated honey samples. Furthermore, most of the observed physicochemical parameters (glucose, fructose, sucrose content, 5-hydroxymethylfurfural (5-HMF) levels, acidity, and electrical conductivity) varied significantly among different types of honey, years, and regions. At the same time, no noticeable difference was found in diastase activity, moisture content, and insoluble matter. Based on the obtained results, 22 honey samples could be considered adulterated, due to the irregular content of sucrose, 5-HMF, acidity, and diastase activity. In addition, 64 honey samples were suspected to be adulterated. Adulterated and non-compliant samples present a relatively low percentage (14.1%) of the total number of investigated samples. Consequently, a considerable number of honey samples met the required standards for honey quality. Overall, these findings provide insights into compositional and quality differences among various types of honey, aiding in understanding their characteristics and potential applications.

Physicochemical properties, multi-elemental composition, and antioxidant activity of five unifloral honeys from Apis cerana cerana

Honey quality is in relation to botanical origin, and physicochemical properties, elemental composition, and antioxidant activity have been used for assessment and identification of honeys. The goal of this study is to contribute to the general analysis of five unifloral honeys from Cocos nucifera L., Dalbergia benthami Prain, Bombax ceiba L., Castanea mollissima Bl., and mangrove in Hainan province, China. Our results revealed that B. ceiba honey had the highest pH (4.27), color (139.33 mm Pfund), ash content (1.03 g/100 g), and electrical conductivity (1312.00 μS/cm) in five unifloral honeys. Furthermore, B. ceiba honey also contained the highest levels of total phenolic content (75.54 mg GAE/100 g) and total flavonoid content (29.22 mg RE/100 g), as well as the strongest antioxidant activity (DPPH IC50 value, 3.97 mg/mL; FRAP value, 6527.43 µmol TE/kg). Moreover, we revealed a considerable variation in element contents in honeys using ICP-MS, with potassium being the most predominant element. B. ceiba honey had the highest contents of K, Ca, Mg, and P, whereas the highest amount of Na was found in mangrove honey. Overall, our data indicated that B. ceiba honey deserves further research as a potential antioxidant agent.

Sunflower Honey-Evaluation of Quality and Stability during Storage

Honey's unique qualities should last for several years when properly stored. Therefore, it is up to manufacturers to choose the right shelf life for their product while also considering the product's nature. Physicochemical parameters (water content, electrical conductivity, free acidity, pH, ash, water-insoluble matter, hydroxymethylfurfural (HMF), sugar content and composition, and diastase activity) were analyzed in 24 samples of sunflower honey collected from several localities in Vojvodina, Serbia. Crystallization indices were also calculated. Furthermore, the impact of eighteen months of room temperature storage (22 ± 2 °C) in a dark place on selected physicochemical parameters (water, HMF, diastase activity, pH value, and free acidity) was investigated. The results of the initial test indicated that the tested samples of sunflower honey from Vojvodina is of good quality because the parameters under examination revealed results that were within the legal bounds of both national and European legislations. Eighteen months of storage at room temperature reduced diastase activity by 2 times, increased HMF content by about 17 times, and decreased the pH value of honey from a mean value of 3.66 to 3.56. The water content was relatively stable at 17.01% before storage and 16.29% after storage. The storage of sunflower honey did not have an impact on the free acidity.

Chemical Analysis and Quality Assessment of Honey Obtained from Different Sources

The purpose of this paper was to evaluate the quality of bee honey from different sources: beekeeper, local market and organic honey. Sensory analysis was performed and the water content, pH, acidity, protein content and total metal content (Cu, Cr, Mn, Co, Ni, Pb, Cd, Fe) were determined. The sensory analysis was carried out by a group of untrained panelists for quality assessment of honey. The metal content was determined by graphite atomic absorption spectrometry (GTAAS). Mineralization was carried out in a microwave digestion system, in a high-pressure polytetrafluoroethylene (PTFE) vessel, using a standard acid-digestion protocol. The results regarding the physico-chemical parameters showed that the honey samples were in accordance with the quality regulations for honey as a commercial product. The concentration of metals in the investigated honey samples varied in the order Cu > Cr > Pb > Fe > Ni > Mn > Co > Cd, the values being within the limits established by the EU Commission (No. 1881/2006). The variations observed in the evaluated parameters can be caused by the difference in plant species from which the honey comes, the harvesting period and the level of environmental pollutants. The Pearson correlations between the physico-chemical parameters and the metals indicate that water content (wc) is strongly negatively correlated with Cd and Ni, while pH is strongly positively correlated with Mn and Fe. Moreover, EC is strongly negatively correlated with Ni and Fe, and the Brix degrees are strongly positively correlated with Cd and Ni. Statistically significant positive correlation was found between Brix–Cd, Ni–Cd and Cu–Cr and a statistically significant negative correlation was detected between wc and Cd.

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.

Polyphenolic and Chemical Profiles of Honey From the Tara Mountain in Serbia

This study presents a detailed characterization of 27 honey samples from the Tara Mountain region in Serbia using different comprehensive techniques and methods. The types of the honey samples were defined as monofloral (4 samples), honeydew (5 samples) and polyfloral (18 samples) honey based on determined polyphenol content, antioxidant activity, electrical conductivity and melissopalynological analyses. Physicochemical parameters such as pH (4.13–4.94), diastase activity (24.20–41.70 DN), acidity (14.60–29.70 meq/kg), content of 5-(hydroxymethyl)furfural (in range below 5, up to 16.90 mg/kg), sucrose (0.20–3.90 g/100 g), and moisture content (15.01–19.23%) confirmed the required quality of the honey samples. Sensory analysis revealed honey characteristics favorable to consumers. Analyses of 19 phenolic compounds using ultra-high-performance liquid chromatography with a diode-array detection and triple quadrupole mass spectrometry (UHPLC-DAD-MS/MS) revealed six phenolic acids and 13 other compounds from the group of flavonoids and their glycosides. In all the samples the highest content was determined for p-coumaric acid, followed by caffeic acid and pinocembrin. Besides total phenolic content and radical scavenging activity, antimicrobial activity was also examined. Most honey samples showed bactericidal activity against Staphylococcus aureus and bacteriostatic activity against Escherichia coli, while none of the honey samples inhibited the growth of Candida albicans. Chemometric analyses were applied for an in-depth study of the results to further evaluate the characteristics of the honey samples studied. Principal component analysis (PCA) was used for assessing the differences in physicochemical parameters, polyphenols content and antioxidant capacity between honey samples. The unrooted cluster tree was used to group the samples based on the melissopalynological analyses.

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.

The Natural Cryoprotectant Honey for Fertility Cryopreservation

Honey is a mixture of 25 sugars with other bioactive substances (i.e., organic acids, enzymes, antioxidants, and vitamins) and has been known as a highly nutritious functional food. Traditionally, it has been widely used in medicinal applications to cure various diseases. The effectiveness of honey in different applications has been used for its antimicrobial activity, absorption of hydrops, cleansing, removing odor, assisting granulation, recovery of nutrition, and formation of tissue and epithelium, which proved that honey has dehydrating and preserving properties to make it ideal for the cryopreservation of cells and tissues. Cryopreservation is an advanced preservation technique for tissue, cells, organelles, or other biological specimen storage, performed by cooling the sample at a very low temperature. It is the most common approach to improved preserving fertility (sperm, embryos, and oocytes) in different species that may undergo various life-threatening illnesses and allows for the genetic screening of these cells to test the sample for diseases before use. However, with toxic cryoprotectant (CPA), cryopreservation of fertility has been challenging because of their particular structure and sensitivity to chilling. Honey’s unique composition, as well as its dehydrating and preserving properties, qualify it to be used as a natural cryoprotectant. The aim of this study is to emphasize the ability of honey as a natural cryoprotectant in cryopreservation. The articles for this review were searched from Google Scholar, PubMed, Science Direct, Web of Science, and Scopus, using the keywords, honey, cryopreservation, natural cryoprotectant/CPAs, extenders, and fertility. Honey, as a natural cryoprotectant in fertility cryopreservation, yielded satisfactory results, with respect to improved post-thaw quality and viability. It is now proved as a non-toxic and highly efficient natural cryoprotectant in fertility preservation because its increasing viscosity at low temperature can provide a protective barrier to cells by reducing ice formation. Furthermore, its antioxidant property plays a vital role in protecting the cells from thermal damage by reducing the reactive oxygen species (ROS). This review provides a road map for future studies to investigate the potential of honey in the cryopreservation of other cells and tissue and contribute to the scientific research, regarding this remarkable natural product.

Levels of trace elements and rare earth elements in honey from Jordan

Honey is a common sweetener in the Jordanian diet with an annual consumption of approximately one thousand tons, two-thirds of which are imported. It is believed that the elemental profile of honey is an indicator of safety and botanical and geographic origin. In the literature, there are a lack of studies concerning the levels of major and trace elements in honey in Jordan. A total of 46 elements, including 15 rare earth elements (REEs), were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) in 18 monofloral and multifloral imported honey samples and 12 multifloral local samples. Regarding monofloral samples, Black Forest samples had the highest total metal content, while acacia samples had the lowest total metal content. Local multifloral honey had the largest Sr and total REE levels, while it had the lowest Mn levels. Very low levels of toxic elements were found in all samples, indicating the safety of honey in Jordan for human consumption. The results of this study showed that a large number of samples (> 100) and the application of advanced statistical models are required to discriminate between multifloral imported and local honey.

A chemometric approach for the differentiation of 15 monofloral honeys based on physicochemical parameters

BACKGROUND

Although the main method for authentication of monofloral honey is pollen analysis, other classification approaches have been also applied. However, the majority of the existing classification models so far have utilized a few honey types or a few honey samples of each honey type, which can lead to inaccurate results. Aiming at addressing this, the goal of the present study was to create a classification model by analysing in total 250 honey samples from 15 different monofloral honey types in ten physicochemical parameters and then, multivariate analysis [multivariate analysis of variance (MANOVA), principal component analysis (PCA) and multi-discriminant analysis (MDA)] was applied in an effort to distinguish and classify them.

RESULTS

Electrical conductivity and colour were found to have the highest discriminative power, allowing the classification of monofloral honey types, such as oak, knotgrass and chestnut honey, as well as the differentiation between honeydew and nectar honeys. The classification model had a high predictive power, as the 84.4% of the group cases was correctly classified, while for the cases of chestnut, strawberry tree and sunflower honeys the respective prediction was correct by 91.3%, 95% and 100%, allowing further determination of unknown honey samples.

CONCLUSION

It seems that the characterization of monofloral honeys based on their physicochemical parameters through the proposed model can be achieved and further applied on other honey types. The results could contribute to the development of methodologies for the determination of honey's botanical origin, based on simple techniques, so that these can be applied for routine analysis. © 2021 Society of Chemical Industry.

Thin-layer chromatography in the authenticity testing of bee-products

Quality control, nutritional value and the monitoring of hazardous residues in honey bee- products have become major topics for both producers and consumers. Due to its potential role in human health, bee-products rich in bioactive compounds are becoming increasingly popular. This review aims to provide an overview of thin-layer chromatography methods used in quality control,authenticity testing and chemical profiling of bee-products in order to help scientists engaged in the field of bee-products chemistry to utilize the advantages of this technique in the detection and elimination of fraudulent practices in bee-product manufacturing. Recently, hyphenation of thin-layer chromatography, image analysis and chemometrics support bee-products analysisbysimultaneousdeterminationofanalytes with different detection principles, identification of individual bioactive compounds as well as structure elucidation of compounds. Highlighted opportunities of thin-layer chromatography could encourage further investigations that would lead to improvements in the detection and elimination of marketing fraudulent practices.

Protective Effect of Honey and Propolis against Gentamicin-Induced Oxidative Stress and Hepatorenal Damages

Bee products are a promising source of phenolic compounds with strong antioxidant activity. The present study was designed to explore the protective effect of honey, propolis, and their combination on gentamicin-induced oxidative stress and hepatorenal dysfunction. This study was conducted on male Wistar rats by intraperitoneal injections of gentamicin (120 mg/kg BW/day, i.p.) or normal saline (1 ml/kg BW/day, i.p.) for 10 consecutive days. Honey (2 g/kg BW), propolis (100 mg/kg BW), or their combination were given daily by gavage to normal and gentamicin groups. Honey and propolis samples were evaluated for their phytochemical composition and antioxidant capacity. The in vitro investigations showed that the evaluated samples especially propolis extract have high antioxidant power associated with the presence of several phenolic compounds such as flavonoids, flavan-3-ols, hydroxybenzoic acids, hydroxycinnamic acids, and stilbenes, while honey contains only hydroxybenzoic acids and hydroxycinnamic acids. It was also shown that simultaneous treatment with honey or propolis extract alone or in association prevented changes caused by gentamicin administration and improved hepatic and renal functions. Changes caused by gentamicin administration, observed by in vivo experiments, include significant elevation of uric acid, urea, creatinine, and hepatic enzyme levels (ALT, AST, and ALP) and kidney biochemical changes (an increase of urea, uric acid, and creatinine and a decrease of albumin and total protein) as well as remarkable changes of renal and liver oxidative stress markers (CAT, GPx, and GSH) and elevation of MDA levels. Overall, it can be concluded that honey and propolis might be useful in the management of liver and renal diseases induced by xenobiotics.

Bioactive Molecules for Discriminating Robinia and Helianthus Honey: High-Performance Liquid Chromatography-Electron Spray Ionization-Mass Spectrometry Polyphenolic Profile and Physicochemical Determinations

Bioactive molecules from the class of polyphenols are secondary metabolites from plants. They are present in honey from nectar and pollen of flowers from where honeybees collect the “raw material” to produce honey. Robinia pseudoacacia and Helianthus annuus are important sources of nectar for production of two monofloral honeys with specific characteristics and important biological activity. A high-performance liquid chromatography–electro spray ionization–mass spectrometry (HPLC–ESI–MS) separation method was used to determine polyphenolic profile from the two types of Romanian unifloral honeys. Robinia and Helianthus honey showed a common flavonoid profile, where pinobanksin (1.61 and 1.94 mg/kg), pinocembrin (0.97 and 1.78 mg/kg) and chrysin (0.96 and 1.08 mg/kg) were identified in both honey types; a characteristic flavonoid profile in which acacetin (1.20 mg/kg), specific only for Robinia honey, was shown; and quercetin (1.85 mg/kg), luteolin (21.03 mg/kg), kaempferol (0.96 mg/kg) and galangin (1.89 mg/kg), specific for Helianthus honey, were shown. In addition, different phenolic acids were found in Robinia and Helianthus honey, while abscisic acid was found only in Robinia honey. Abscisic acid was correlated with geographical location; the samples collected from the south part of Romania had higher amounts, due to climatic conditions. Acacetin was proposed as a biochemical marker for Romanian Robinia honey and quercetin for Helianthus honey.

The Use of Ultrasound for Preventing Honey Crystallization

The aim of this study was to evaluate the effect of ultrasound treatment for preventing honey crystallization on the physicochemical and microbiological properties of unifloral honey and polyfloral honey. Honey samples without any treatment were used as a control group for comparison. The effect of applying ultrasound treatment was evaluated by studying over time the tendency of crystallization, the rheological properties of honey and chemical and microbiological properties. The parameters analyzed for the two groups of samples (treated and untreated with ultrasound), which did not vary or had small variations during the research were water content, acidity, water activity, glucose, fructose, sucrose, glucose/water ratio, glucose/fructose ratio. The crystallization process was installed in the control samples from the first month of the study, and much later in the treated samples. The color of the untreated samples varied considerably, and the color of the treated ones remained stable or slightly varied. For the control samples, the smallest variation in hydroxymethylfurfural (HMF) concentration was in raspberry honey (5%), and the most significant variation was in honeydew honey (30%). For the treated samples, the largest variation of this parameter was found in tillia honey (127%), and the smallest variation was in rapeseed honey (26%). The microbiological quality was higher for the treated samples. In the ultrasound-treated samples of acacia honey, honeydew honey and grassland honey, yeasts, molds or standard plate counts (SPCs) were undetectable. For control samples, SPC values were <10-50 cfu/g. Ultrasound-treated samples maintained their SPC parameter levels or were thus reduced (<10-20 cfu/g). Yeasts and molds were undetectable or had value between <10 and 10 cfu/g. The yeasts and the molds ranged in the control samples between <10 and 40 cfu/g.

Characterization of Serbian sunflower honeys by their physicochemical characteristics

Five physicochemical parameters (water content, electrical conductivity, total acidity (pH), ash mass fraction and concentration of free acids) were analyzed in 15 sunflower honeys collected from several localities in Vojvodina, Serbia. The mean values of analyzed honeys were: water content 16.87%; concentration of free acids 27.43 mEq/kg; electrical conductivity 0.34 mS/cm; pH 3.64 and ash mass fraction 0.13%. The selected physicochemical characteristics of all honey samples from Serbia analyzed in this research can be considered to be within the parameters expected for sunflower honey in general. The values for ash mass fraction, electrical conductivity and concentration of free acids in all sunflower honey samples showed similar trends. High correlation was established between electrical conductivity and ash mass fraction. Statistically significant difference (p≤0.05) was established only for average values of free acids concentration between honey samples originating from the localities Kanjiža and Čelarevo. All of the analyzed honey samples were found to meet national and European legislation for investigated parameters

High-Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD) and Chemometrics for Geographical and Floral Authentication of Honeys from Southern Italy (Calabria region)

High-performance anion exchange chromatography with pulsed amperometric detection (HPAEC–PAD) combined with chemometric analysis was developed to describe, for the first time, the sugar profile of sixty-one honeys of different botanical origin produced in southern Italy (Calabria Region). The principal component and linear discriminant analysis used to describe the variability of sugar data were able to discriminate the honeys according to their botanical origin with a correlation index higher than 90%. For the purpose of the robustness of the conclusions of this study, the analytical advantages of the HPAEC–PAD method have been statistically demonstrated compared to the official Italian HPLC–RI method (Refractive Index detection). Finally, as the characterization of the floral and geographical origin of honey became an important issue due to high consumer demand, 13 acacia honeys originating from Europe and China were studied by using the same method. By chemometric method it was possible to discriminate the different geographical origin with an index of 100%. All results proved the possibility to identify the sugar profile obtained by HPAEC–PAD combined with a robust statistical analysis, as a tool of authentication.

Antioxidant Activity, Total Phenolic Content, Individual Phenolics and Physicochemical Parameters Suitability for Romanian Honey Authentication

The present study aimed to evaluate the physicochemical characteristics of honey (raspberry, mint, rape, sunflower, thyme and polyfloral) produced in Romania. The honey samples were from the 2017 to 2018 harvest and were subjected to melissopalynological analysis, alongside the determination of the following physicochemical parameters: moisture content, pH, free acidity, electrical conductivity (EC), hydroxymethylfurfural (HMF) content, color, total polyphenols content (TPC), flavonoids content (FC), DPPH radical scavenging activity, phenolic acids, flavonols, sugars and organic acids in order to evaluate the usefulness of this parameters for the classification of honey according to botanical origin. The results of the melissopalynological analysis revealed that five types of honey samples had a percentage of pollen grains above the minimum of 45%, which was required in order to classify the samples as monofloral honey. The total polyphenols content reached the maximum value in the case of dark honey such as mint honey, followed by raspberry, thyme and polifloral honey. Fructose, glucose, maltose, sucrose, turanose, trehalose, melesitose, and raffinose were identified and quantified in all samples. Gluconic acid was the main organic acid in the composition of all honey samples. Principal component analysis (PCA) confirmed the possibility of the botanical authentication of honey based on these physicochemical parameters.

Physicochemical Properties, Mineral Content, Antioxidant Activities, and Microbiological Quality of Bupleurum spinosum Gouan Honey from the Middle Atlas in Morocco

Monofloral honeys (Bupleurum Spinosum) collected from different geographical locations of Moroccan Middle Atlas were evaluated for various potential attributes. For physicochemical parameters, the results showed the following values: pH (4.02–4.81); free acidity (12.16–31.85 mEq/kg); lactonic acidity (4.98–14.14 mEq/kg); total acidity (18.37–45.53 mEq/kg); moisture (15.81–19.20%); ash (0.21–0.55); electrical conductivity (427.38–682.16 mS/cm); diastasic activity (10.76–26.01); TSS (80.40–84.20%); melanoidins (0.21–1.15), and Pfund scale (30.47–175.53 mm). Potassium was the most important mineral among the tent evaluated elements, followed by sodium and calcium. All tested samples have high antioxidant activities and correlate with phenols, flavonoids, and ascorbic acid content. In regards to safety (sulfite-reducing clostridia and Salmonella spp.) and sanitary quality (faecal coliforms), all honey samples were negative. In addition, low counts of yeast and molds were detected, and the values of total aerobic mesophilic bacteria and Bacillus Sp. confirm the good quality of honey. The outcome of this study showed that all samples have good physicochemical properties, high antioxidant activities, and acceptable microbiological state, respecting the quality control criteria set by the international norms.

Comparative study of physio-chemical analysis of fresh and branded honeys from Pakistan

Honey is a nutritious substance produced by bees. Its quality and nutritional value is of great importance for consumers. Keeping this in view physicochemical and minerals determination as quality parameters of fresh floral Pakistani honeys produced by A. mellifera and branded honeys was conducted. The results of fresh honey indicated average means of Color as 48.78 mmPfund, pH 4.9, Total acidity 37.14 meq/kg, Moisture content 18.62%, Electrical conductivity 0.23 mS/cm, Ash content 0.49%, HMF content 30.85 mg/kg, Proline 365.84 mg/kg, Diastase activity 34.39(DN) and Invertase activity was 68.61(IN) comparable to honey standards. Natural honey were rich in k+ (408.46 ppm) and Na+ (405 ppm). Although Ca+ was very low. Whereas, Co, Mn and Ba concentrations exceed the 1 ppm. However, Pb, Cr, and Mo were unnoticeable. Similarly, Color, pH, MC, EC, T. Acidity, HMF, Proline, Ash content, Diastase and Invertase activity of branded honey samples average means found were 42.5 mmPfund, 5.05, 20.5%, 0.18 mS/cm, 15.34 meq/kg, 36.5 mg/kg, 181.6 mg/kg, 1.11%, 7.90(DN) and 36.97(IN) respectively. The findings showed that fresh honey samples were good and of consumable quality as per honey standards than branded honey. Higher HMF content and lower enzymatic activity in branded honey sample than the Codex standards revealed its either long or improper storage.

Using natural honey as an anti-oxidant and thermodynamically efficient cryoprotectant in embryo vitrification

Embryo cryopreservation is a common practice in reproductive biology and infertility treatments. Despite major improvements over years, the cryoprotectant solutions are still a major source of concern, mostly due to their chemical toxicity and suboptimal protection against cryoinjuries. In this work, we introduced natural honey as a non-permeating cryoprotectant to replace traditionally used sucrose in embryo vitrification. The proposed media were compared with conventional ones by evaluating vitrified/warmed mouse embryos based on their re-expansion, hatching rate and transcription pattern of selected genes involved in heat-shock response, apoptosis and oxidative stress. Despite the similar high re-expansion rate, molecular fingerprint of the cryopreservation is remarkably reduced when honey is used instead of sucrose. The biological response of the proposed media was explained from a fundamental point of view using antioxidant analysis, DSC and GC techniques. It was found that the proposed honey-based medium is less thermodynamically prone to ice formation, which along with its antioxidant capacity can control the production of oxygen radicals and minimize the stress-induced transcriptional response. Furthermore, this work tries to correlate the physico-chemical properties of the vitrification solutions with the cellular and molecular aspects of the cryopreservation and proposes the application of natural cryoprotectants in cryobiology.

Volatile Profile and Physico-Chemical Analysis of Acacia Honey for Geographical Origin and Nutritional Value Determination

Honey composition and color depend greatly on the botanical and geographical origin. Water content, water activity and color of 50 declared acacia samples, collected from three different geographical zones of Romania, together with chromatographic determination of sugar spectrum were analyzed. A number of 79 volatile compounds from the classes of: Alcohols, aldehydes, esters, ketones, sulphur compounds, aliphatic hydrocarbons, nitrogen compounds, carboxylic acids, aromatic acids and ethers were identified by solid-phase micro-extraction and gas-chromatography mass spectrometry. The overall volatile profile and sugar spectrum of the investigated honey samples allow the differentiation of geographical origin for the acacia honey samples subjected to analysis. The statistical models of the chromatic determination, physicochemical parameters and volatile profile was optimal to characterize the honey samples and group them into three geographical origins, even they belong to the same botanical origin.

Discrimination of Natural Mature Acacia Honey Based on Multi-Physicochemical Parameters Combined with Chemometric Analysis

Honey maturity is an important factor in evaluating the quality of honey. We established a method for the identification of natural mature acacia honey with eighteen physicochemical parameters combined with chemometric analysis. The analysis of variance showed significant differences between mature and immature acacia honey in physicochemical parameters. The principal component analysis explained 82.64% of the variance among samples, and indicated that total phenolic content, total protein content, and total sugar (glucose, fructose, sucrose) were the major variables. The cluster analysis and orthogonal partial least squares-discriminant analysis demonstrated that samples were grouped in relation to the maturity coinciding with the results of the principal component analysis. Meanwhile, the 35 test samples were classified with 100% accuracy with the method of multi-physicochemical parameters combined with chemometric analysis. All the results presented above proved the possibility of identifying mature acacia honey and immature acacia honey according to the chemometric analysis based on the multi-physicochemical parameters.

Towards better quality criteria of European honeydew honey: Phenolic profile and antioxidant capacity

Concerning the particular nutritive value of honeydew honey compared to blossom honey, and small number of studies defining botanical origin of honeydew honey, comprehensive analysis of phenolic profile of 64 honeydew honey samples of specific botanical origin was performed. Two advanced techniques of liquid chromatography hyphenated with mass spectrometry were used for identification of a total of 52 compounds and quantification of 25 of them. Pattern recognition analysis applied on data on phenolic compounds content confirmed that quercetin, naringenin, caffeoylquinic acid, hydroxyphenylacetic acid, apigenin and genistein, could be considered as potential markers of botanical origin of honeydew honey. Spectroscopic and electrochemical approaches were applied for the evaluation of the antioxidant capacity. Quercus sps. samples, Quercus frainetto and Quercus ilex, showed high biological activity and specific chemical composition. Additionally, cyclic voltammetry profiles were used for characterization and natural clustering of honeydew honey for the first time.

Enzyme activity, amino acid profiles and hydroxymethylfurfural content in Ethiopian monofloral honey

The enzymes activity, hydroxymethylfurfural (HMF) and amino acids in honeys are relatively low. However, they play very significant role for honey quality. In this study, enzymes, amino acids and HMF contents of Ethiopian monofloral honeys were investigated. Diastase, invertase and HMF were analyzed based on the Harmonized International Honey Commission method and amino acids using amino acids analyzer (HPLC). Diastase activity ranged from 3.91 ± 0.730 (Schefflera abyssinica) to 13.6 ± 2.30 [Becium grandiflorum (L: Lalibella)]; invertase 36.5 ± 1.93 (Leucas abyssinica) to 4.85 ± 2.36 (Schefflera abyssinica); and HMF 0 ± 0 (Hypoestes and Leucas abyssinica) to 3.37 ± 1.73 (Croton macrostachyus). Significant variations were observed among Schefflera abyssinica honeys in diastase content, despite being from the same botanical origin. Significant variations were also observed among Becium grandiflorum honeys in invertase and diastase contents. Bees' geographical race and location affected enzymes activities. Lower level of enzymes could be an intrinsic characteristic of Ethiopian honey. Thus, enzymes activity alone cannot be a worthwhile indicator of quality for Ethiopian honey; besides diastase and invertase activity, the quality control of Ethiopian honeys should be supported by HMF parameters.

Characterization of Argentine honeys on the basis of their mineral content and some typical quality parameters

Background

The levels of 19 elements (As, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Se, Tl, U, V, Zn) from sixteen different Argentine production sites of unifloral [eucalyptus (Eucaliptus rostrata), chilca (Baccharis salicifolia), Algarrobo (Prosopis sp.), mistol (Ziziphus mistol) and citric] and multifloral honeys were measured with the aim to test the quality of the selected samples. Typical quality parameters of honeys were also determined (pH, sugar content, moisture). Mineral elements were determined by using inductively coupled plasma mass spectrometer (ICP-MS DRC). We also evaluated the suitability of honey as a possible biomonitor of environmental pollution. Thus, the sites were classified through cluster analysis (CA) and then pattern recognition methods such as Principal Component Analysis (PCA) and discriminant analysis (DA) were applied.

Results

Mean values for quality parameters were: pH, 4.12 and 3.81; sugar 82.1 and 82.0 °brix; moisture, 16.90 and 17.00% for unifloral and multifloral honeys respectively. The water content showed good maturity. Likewise, the other parameters confirmed the good quality of the honeys analysed. Potassium was quantitatively the most abundant metal, accounting for 92,5% of the total metal contents with an average concentration of 832.0 and 816.2 μg g^-1 for unifloral and multifloral honeys respectively. Sodium was the second most abundant major metal in honeys with a mean value of 32.16 and 33.19 μg g^-1 for unifloral and multifloral honeys respectively. Mg, Ca, Fe, Mn, Zn and Cu were present at low-intermediate concentrations. For the other 11 trace elements determined in this study (As, Be, Cd, Co, Cr, Ni, Pb, Se, Tl, U and V), the mean concentrations were very low or below of the LODs. The sites were classified through CA by using elements’ and physicochemical parameters data, then DA on the PCA factors was applied. Dendrograms identified three main groups. PCA explained 52.03% of the total variability with the first two factors.

Conclusions

In general, there are no evidences of pollution for the analysed honeys. The analytical results obtained for the Argentine honeys indicate the products’ high quality. In fact, most of the toxic elements were below LODs. The chemometric analysis combining CA, DA and PCA showed their aptness as useful tools for honey’s classification. Eventually, this study confirms that the use of honey as biomonitor of environmental contamination is not reliable for sites with low levels of contamination.

Determination of the botanical origin of honey by front-face synchronous fluorescence spectroscopy

Front-face synchronous fluorescence spectroscopy combined with chemometrics is used to classify honey samples according to their botanical origin. Synchronous fluorescence spectra of three monofloral (linden, sunflower, and acacia), polyfloral (meadow mix), and fake (fake acacia and linden) honey types (109 samples) were collected in an excitation range of 240-500 nm for synchronous wavelength intervals of 30-300 nm. Chemometric analysis of the gathered data included principal component analysis and partial least squares discriminant analysis. Mean cross-validated classification errors of 0.2 and 4.8% were found for a model that accounts only for monofloral samples and for a model that includes both the monofloral and polyfloral groups, respectively. The results demonstrate that single synchronous fluorescence spectra of different honeys differ significantly because of their distinct physical and chemical characteristics and provide sufficient data for the clear differentiation among honey groups. The spectra of fake honey samples showed pronounced differences from those of genuine honey, and these samples are easily recognized on the basis of their synchronous fluorescence spectra. The study demonstrated that this method is a valuable and promising technique for honey authentication.

Amino acids profile of Serbian unifloral honeys

BACKGROUND

The free amino acids profile of 192 samples of seven different floral types of Serbian honey (acacia, linden, sunflower, rape, basil, giant goldenrod, and buckwheat) from six different regions was analysed in order to distinguish honeys by their botanical origin.

RESULTS

The most abundant amino acids were proline, alanine, phenylalanine, threonine and arginine. Based on the established amino acids profiles, some important differences have been identified among studied honey samples relying on the basic descriptive statistics data, and confirmed by multivariate chemometric methods. Principal component analysis revealed that basil honey samples form a well-defined cluster imposed with phenylalanine content. The model obtained by linear discriminant analysis might be used to distinguish basil honey from the rest of the samples, and has moderate predictive power to separate genuine acacia, linden, sunflower and rape honeys. New data for the amino acids profile of giant goldenrod and buckwheat honey samples are presented.

CONCLUSIONS

The floral origin of honey could be successfully evaluated by its amino acids profile coupled with chemometric analysis.

Phenolic profile and antioxidant activity of Serbian polyfloral honeys

A total of 58 polyfloral honey samples from different regions in Serbia were studied to determine their phenolic profile, total phenolic content and antioxidant capacity. UHPLC-LTQ OrbiTrap MS made possible the identification of 36 compounds: 24 flavonoids, two abscisic acids, and 10 phenolic acids and their derivatives. Quantification was done using 14 available standards. Data on phenolics and abscisic acids allowed the discrimination and classification of honeys in accordance to their geographical origin, using pattern recognition techniques, principal component analysis and partial least squares discriminant analysis. Samples originated from Vojvodina and Zlatibor region were clearly distinguished from those from the rest of Serbia because of the presence of dicaffeoylquinic acid, ellagic acid, caffeic acid phenethyl ester, and chlorogenic acid, among others. A good correlation (r = 0.865) was observed between total phenolic content and radical-scavenging activity. Total phenolic content ranged from 0.03 to 1.39 mg GAE/g and radical scavenging activity ranged from 1.31% to 25.61%.

Authentication of monofloral Yemeni Sidr honey using ultraviolet spectroscopy and chemometric analysis

This work describes a simple model developed for the authentication of monofloral Yemeni Sidr honey using UV spectroscopy together with chemometric techniques of hierarchical cluster analysis (HCA), principal component analysis (PCA), and soft independent modeling of class analogy (SIMCA). The model was constructed using 13 genuine Sidr honey samples and challenged with 25 honey samples of different botanical origins. HCA and PCA were successfully able to present a preliminary clustering pattern to segregate the genuine Sidr samples from the lower priced local polyfloral and non-Sidr samples. The SIMCA model presented a clear demarcation of the samples and was used to identify genuine Sidr honey samples as well as detect admixture with lower priced polyfloral honey by detection limits >10%. The constructed model presents a simple and efficient method of analysis and may serve as a basis for the authentication of other honey types worldwide.