5-HMF and carbohydrates content in stingless bee honey by CE before and after thermal treatment

Rainy and Dry Seasons Are Relevant Factors Affecting Chemical and Antioxidant Properties of Meliponini Honey

Brazilian stingless bee species produce honey with distinct physicochemical and bioactive properties shaped by environmental factors. This study investigated the effects of the rainy and dry seasons on the physicochemical characteristics, chemical fingerprinting, mineral content, and antioxidant capacity of honey from Melipona mondury and Melipona bicolor. The honey samples were analyzed for their phytochemical properties (official methods), total phenolics (Folin-Ciocalteu method), flavonoid content (aluminum complex formation method), antioxidant capacity (FRAP and ABTS assays), and antioxidant activity (erythrocyte model). The mineral content was assessed via TXRF spectroscopy, and chemical fingerprinting was conducted using mass spectrometry. Chemometric tools were used for the samples' discriminating analyses, including Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA). Seasonal variations significantly affected the moisture, total soluble solids, and acidity. In turn, the antioxidant capacity was influenced mainly by the bee species. The mineral composition, particularly potassium, phosphorus, and calcium, remained stable. Multivariate analysis identified m/z ions (VIP scores > 2.5), rather than physicochemical or antioxidant capacity parameters, as critical for seasonal discrimination. The antioxidant activity, assessed by oxidative hemolysis prevention, was robust across the seasons, with M. mondury honey (2 mg·mL-1) from the rainy season outperforming ascorbic acid. These findings underscore the impact of the rainy and dry seasons and the potential of secondary metabolite fingerprinting to identify collection periods.

The Physicochemical Parameters, Phenolic Content, and Antioxidant Activity of Honey from Stingless Bees and Apis mellifera: A Systematic Review and Meta-Analysis

The most common bee species used for honey production is Apis mellifera (A. mellifera), followed by stingless bees. This study included scientific articles using the PRISMA approach. A random effect model was implemented and the effect size (ES) was calculated and reported as the standardized mean difference (SMD) and raw mean difference (RMD). The mean phenolic content in A. mellifera honey was 61.21 ± 28.3 mg GAE/100 g and stingless bee honey +33.69 mg GAE/100 g; p = 0.01. The antioxidant activity, discovered by the Ferric Reducing Antioxidant Power (FRAP) method, showed a mean of 97.34 ± 7.84 μmol Fe(II)/100 g in A. mellifera and stingless bee honey +63.39 μmol Fe(II)/100 g; p = 0.009. The physicochemical properties showed significant differences in moisture (A. mellifera honey 19.54 ± 3.65%; stingless bee honey +8.02%; p = 0.0001), hydroxymethylfurfural (HMF) (A. mellifera honey 20.14 ± 16.27 mg/kg; stingless bee honey -11.25 mg/kg; p = 0.001), and free acidity (A. mellifera honey 31.32 ± 16.67 meq/kg; stingless bee honey +34.76 meq/kg; p = 0.01). The variability in the trials was explained by the heterogeneity, and a meta-regression analysis incorporated four covariates: (1) stingless bee species; (2) floral source; (3) country, and (4) latitude. This study highlights the importance of conducting further studies on stingless bee honey.

Physicochemical properties of stingless bees (Meliponula beccarii) honey in Dandi and Meta Robi districts of West Shewa zone, Ethiopia

The study was conducted to characterize the physicochemical properties of honey produced from underground nesting stingless bees (Meliponula beccarii) in the Dandi and Meta Robi districts of the West Shewa zone, Ethiopia. A total of 27 honey samples, including 24 samples collected through careful investigation and excavation of natural nests and 3 samples purchased from the market, were analyzed in the laboratory. The evaluated physicochemical properties showed an overall mean of 306.64±87.95 meq./kg free acidity, 28.05±3.52% moisture content, 1.31±0.44 mS/cm electrical conductivity, 3.29±0.16 pH, 0.89±1.14 mg/kg HMF, 0.63±0.24% mineral (ash), 9.39±4.26% glucose, 0.24±0.01 g/100g sucrose, 10.81±4.95 g/100g maltose, and 16.57±2.55 g/100g fructose, turanose (0.20 ± 0.00 g/100g). The differences between the two district's honey samples were significant (p > 0.05) for fructose value and considerable for free acidity, moisture content, and pH values. The honey samples purchased from the market showed similar physicochemical properties to the honey from the feral nests, with a mean of 314.33±88.72 meq./kg free acidity, 27.73±2.52% moisture content, 1.43±0.41 mS/cm electrical conductivity, 3.26±0.13 pH, 0.95±1.23 mg/kg HMF, 0.59±0.19% mineral (ash), 10.11±4.11% glucose, 0.25±0.02 g/100g sucrose, 11.23±4.52 g/100g maltose, and 16.33±2.41 g/100g fructose. The study found that the stingless bee honey from the study areas had distinctive low HMF, high free acidity, and low pH values, which may indicate the honey's potential medicinal properties. The high free acidity in the Meliponula beccarii honey appear unusually elevated compared to other stingless bee honey and the Codex Alimentarius standards for Apis honey, suggesting increased fermentation that can originate from the bee species, plant and geographical origins, improper handling, and high moisture content. This study demonstrated that the honey in the study areas has distinctive physicochemical properties from A. mellifera-produced honey, which may support its traditional medicinal uses. Further detailed studies on ground-nesting and other stingless species' honey medicinal values are recommended to provide scientific evidence.

The Potential of Dehydrated Geniotrigona thoracica Stingless Bee Honey against Metabolic Syndrome in Rats Induced by a High-Carbohydrate, High-Fat Diet

BACKGROUND/OBJECTIVES

Metabolic syndrome (MS) is diagnosed when at least three out of five key risk factors are present: obesity, high blood pressure, insulin resistance, high triglycerides (TG) and low high-density lipoprotein (HDL). MS is often associated with chronic low-grade inflammation. Recent studies have shown that raw stingless bee honey (SBH) can alleviate MS risk factors. However, the high moisture content in raw SBH predisposes it to fermentation, which can degrade its quality. Therefore, dehydrating SBH is necessary to prevent the fermentation process. This study aimed to compare the effects of dehydrated (DeGT) and raw (RGT) SBH from Geniotrigona thoracica species on high-carbohydrate, high-fat diet (HCHF)-induced MS in rats.

METHODS

Twenty-four male Wistar rats were divided into four groups: control (C), HCHF-induced MS without treatment (MS), HCHF-induced MS treated with DeGT (MS+DeGT) and HCHF-induced MS treated with RGT (MS+RGT). Group C received standard rat chow, while the other groups were fed with HCHF diet for 16 weeks. In the final eight weeks, two HCHF-induced groups received their respective SBH treatments.

RESULTS

Both DeGT and RGT treatments reduced energy intake, fat mass, high blood pressure, inflammatory (tumour necrosis factor-alpha (TNF-α)) and obesity (the leptin/adiponectin (L/A) ratio, corticosterone, 11 beta-hydroxysteroid dehydrogenase type-1 (11βHSD1)) markers, as well as prevented histomorphometry changes (prevented adipocyte hypertrophy, increased the Bowman's space area and glomerular atrophy). Additionally, DeGT increased serum HDL levels, while RGT reduced serum TG, leptin and other inflammatory markers (interleukin-6 (IL-6) and interleukin-1 beta (IL-1β)), as well as hepatosteatosis.

CONCLUSIONS

While DeGT demonstrates potential as a preventive agent for MS, RGT exhibited more pronounced anti-MS effects in this study.

In vitro testing of honey quality and biological functionality: underestimated elements in the clinical testing of honey

Honey is an attractive functional food that often becomes a subject of clinical studies on the treatment of diverse diseases. However, the clinical efficacy of honey is rather controversial due, at least in part, to its variable composition and botanical origin as well as thermal processing or improper storage conditions. This review addresses the importance of honey quality standards and in vitro testing of the biological properties of honey prior to performing clinical studies, which can have a great impact on clinical outcomes. It focused on recently performed meta-analyses and systematic reviews where honey was used in the management of various disorders including respiratory tract infections, and metabolic and cardiometabolic diseases, with the goal of characterising the honeys used in clinical studies. In addition, it provides recommendations for the use and storage of honey for clinical testing. The vast majority of clinical studies included in meta-analyses do not provide any information about honey quality parameters. In fact, indicators of thermal damage or prolonged storage of honey were analysed only in one clinical study. This observation highlights on the alarming status of honey quality in clinical studies. Furthermore, in vitro biological properties of the analysed honeys were assessed in two clinical studies. Therefore, this review strongly advocates the clinical use of only fully characterised honey samples of known botanical origin with proven in vitro biological functionality and no or minimal thermal processing.

Impact of prolonged storage on quality assessment properties and constituents of honey: A systematic review

This systematic review paper aims to discuss the trend in quality assessment properties and constituents of honey at different storage conditions and confer the possible whys and wherefores associated with the significant changes. Initially, a literature search was conducted through Google Scholar, ScienceDirect, PubMed, and Scopus databases. In total, 43 manuscripts published between 2001 and 2023 that met the inclusion and exclusion criteria were chosen for the review. As an outcome of this review, prolonged honey storage could deteriorate sensory, nutritional, and antioxidant properties and promote fermentation, granulation, microbial growth, carcinogenicity, organotoxicity, and nephrotoxicity. This systematic review also recognized that diastase activity, invertase activity, 5-hydroxymethylfurfural content, proline content, sugar content, amino acids, and vitamins could be used as indicators to distinguish fresh and stored honey based on the significant test (p-value) in the reported studies. However, all the reported studies used the simplest approach (one-way ANOVA) to identify the significant differences in the analyzed parameter during the storage period and none of them reported an approach to identify the most influential parameter at different storage conditions. In conclusion, orthogonal partial least squares discriminant analysis (supervised multivariate statistical tool) has to be employed in future studies to find the most influential parameter and could be used to potent chemical markers to distinguish fresh and stored honey because this analysis is incorporated with S-plot, variable importance of projection, and one-way ANOVA, which can produce the most accurate and precise results rather solely depending on one-way ANOVA.

Differentiation of High-Fructose Corn Syrup Adulterated Kelulut Honey Using Physicochemical, Rheological, and Antibacterial Parameters

Kelulut (stingless bee) honey (KH) possesses a wide range of benefits for human consumption and can exhibit medical effects. Due to its high value, this premium honey is often adulterated with different types of cheaper sugars, causing low nutrients and potential food safety threats in the final product. This study aims to determine the physicochemical, rheological, and antibacterial properties of sugar-based adulterated KH from the stingless bee species Heterotrigona itama. Adulterated samples were prepared using pure honey mixed with different concentrations of high fructose corn syrup (HFCS), i.e., 10%, 20%, 30%, 40%, and 50%. Water activity, colour, total soluble solids, pH, turbidity, viscosity, and antimicrobial activity of KH were determined. In addition, the primary sugar composition (fructose, glucose, and trehalulose) was determined by high-performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD). This study shows that the increasing percentage of HFCS addition in the KH samples significantly increases (p < 0.05) the total soluble solids, colour, pH, turbidity, viscosity, glucose, and fructose content; meanwhile, the water activity and trehalulose were reduced significantly (p < 0.05). Antimicrobial activity against S. aureus was reduced significantly (p = 0.006) by an increased percentage of HFCS compared to Control. Antimicrobial activity against P. aeruginosa was also found to be reduced significantly but showed non-significant effect from an increased percentage of HFCS in honey (p = 0.413). The bacterium S. aureus was more vulnerable to treatment with honey from both Control and adulterated groups compared to P. aeruginosa. In conclusion, HFCS-adulterated KH and authentic KH can be differentiated using all the parameters investigated. These data are vital for the governing bodies to ensure that KH sold in the markets is free from HFCS adulteration.

Graphene quantum dots incorporated NiAl2O4 nanocomposite based molecularly imprinted electrochemical sensor for 5-hydroxymethyl furfural detection in coffee samples

5-Hydroxymethyl furfural (HMF) is an intermediate produced by dehydrating sugars, such as fructose, sucrose, and glucose, in an acidic medium or during the Maillard reaction. It also occurs due to the storage of sugary foods at inappropriate temperatures. In addition, HMF is seen as a quality criterion in products. In this study, a novel molecularly imprinted electrochemical sensor based on graphene quantum dots incorporated NiAl₂O₄ (GQDs-NiAl₂O₄) nanocomposite was presented for the selective determination of HMF in coffee samples. Various microscopic, spectroscopic, and electrochemical methods were carried out for the structural characterizations of GQDs-NiAl₂O₄ nanocomposite. The molecularly imprinted sensor was prepared by multi-scanning using cyclic voltammetry (CV) in the presence of 100.0 mM pyrrole monomer and 25.0 mM HMF. After method optimization, the sensor revealed linearity towards HMF in the range of 1.0-10.0 ng L^-1 with a detection limit (LOD) of 0.30 ng L^-1. The developed MIP sensor's high repeatability, selectivity, stability, and fast response ability can provide reliable HMF detection in beverages, such as coffee, which is heavily consumed.

Insight into the Recent Application of Chemometrics in Quality Analysis and Characterization of Bee Honey during Processing and Storage

The application of chemometrics, a widely used science in food studies (and not only food studies) has begun to increase in importance with chemometrics being a very powerful tool in analyzing large numbers of results. In the case of honey, chemometrics is usually used for assessing honey authenticity and quality control, combined with well-established analytical methods. Research related to investigation of the quality changes in honey due to modifications after processing and storage is rare, with a visibly increasing tendency in the last decade (and concentrated on investigating novel methods to preserve the honey quality, such as ultrasound or high-pressure treatment). This review presents the evolution in the last few years in using chemometrics in analyzing honey quality during processing and storage. The advantages of using chemometrics in assessing honey quality during storage and processing are presented, together with the main characteristics of some well-known chemometric methods. Chemometrics prove to be a successful tool to differentiate honey samples based on changes of characteristics during storage and processing.

Honey on brain health: A promising brain booster

Since ancient times, honey has been employed in many aspects of everyday life, the most popular of which is as a natural sweetener. Honey is used not only as a nutritional product but also in health as a supplement and in various applications, especially related to brain booster health. Brain health is the capacity to carry out all mental functions necessary for cognition, such as learning and judging, utilizing language, and recalling. This review presents the current trend of research on honey, particularly the interest in underlying mechanisms related to brain booster health. A total of 34 original articles addressing brain health from the consumption of honey were analyzed. We identified four main brain health benefits, which are memory booster, neuroprotective effect, anti-stress, and anti-nociceptive potentials with the proposed underlying mechanism. A lot of attention has been paid to the role that honey plays in brain health research, with the goal of examining the link between honey and brain health as well as the mechanism underlying it, the findings from this review may be potentially beneficial to develop new therapeutic roles for honey to help determine the best and most promising to benefit and boost overall brain health.

Antioxidant Activity and Phenolic Compound Identification and Quantification in Western Australian Honeys

This study reports on the total phenolic content and antioxidant activity as well as the phenolic compounds that are present in Calothamnus spp. (Red Bell), Agonis flexuosa (Coastal Peppermint), Corymbia calophylla (Marri) and Eucalyptus marginata (Jarrah) honeys from Western Australia. The honey's total phenolic content (TPC) was determined using a modified Folin-Ciocalteu assay, while their total antioxidant activity was determined using FRAP and DPPH assays. Phenolic constituents were identified using a High Performance Thin-Layer Chromatography (HTPLC)-derived phenolic database, and the identified phenolic compounds were quantified using HPTLC. Finally, constituents that contribute to the honeys' antioxidant activity were identified using a DPPH-HPTLC bioautography assay. Based on the results, Calothamnus spp. honey (n = 8) was found to contain the highest (59.4 ± 7.91 mg GAE/100 g) TPC, followed by Eucalyptus marginata honey (50.58 ± 3.76 mg GAE/100 g), Agonis flexuosa honey (36.08 ± 4.2 mg GAE/100 g) and Corymbia calophylla honey (29.15 ± 5.46 mg GAE/100 g). In the FRAP assay, Calothamnus spp. honey also had the highest activity (9.24 ± 1.68 mmol Fe²⁺/kg), followed by Eucalyptus marginata honey (mmol Fe²⁺/kg), whereas Agonis flexuosa (5.45 ± 1.64 mmol Fe²⁺/kg) and Corymbia calophylla honeys (4.48 ± 0.82 mmol Fe²⁺/kg) had comparable FRAP activity. In the DPPH assay, when the mean values were compared, it was found that Calothamnus spp. honey again had the highest activity (3.88 ± 0.96 mmol TE/kg) while the mean DPPH antioxidant activity of Eucalyptus marginata, Agonis flexuosa, and Corymbia calophylla honeys were comparable. Kojic acid and epigallocatechin gallate were found in all honeys, whilst other constituents (e.g., m-coumaric acid, lumichrome, gallic acid, taxifolin, luteolin, epicatechin, hesperitin, eudesmic acid, syringic acid, protocatechuic acid, t-cinnamic acid, o-anisic acid) were only identified in some of the honeys. DPPH-HPTLC bioautography demonstrated that most of the identified compounds possess antioxidant activity, except for t-cinnamic acid, eudesmic acid, o-anisic acid, and lumichrome.

A Comprehensive HPTLC-Based Analysis of the Impacts of Temperature on the Chemical Properties and Antioxidant Activity of Honey

Honeys are commonly subjected to a series of post-harvest processing steps, such as filtration and/or radiation treatment and heating to various temperatures, which might affect their physicochemical properties and bioactivity levels. Therefore, there is a need for robust quality control assessments after honey processing and storage to ensure that the exposure to higher temperatures, for example, does not compromise the honey's chemical composition and/or antioxidant activity. This paper describes a comprehensive short-term (48 h) and long-term (5 months) study of the effects of temperature (40 °C, 60 °C and 80 °C) on three commercial honeys (Manuka, Marri and Coastal Peppermint) and an artificial honey, using high-performance thin-layer chromatography (HPTLC) analysis. Samples were collected at baseline, at 6 h, 12 h, 24 h and 48 h, and then monthly for five months. Then, they were analysed for potential changes in their organic extract HPTLC fingerprints, in their HPTLC-DPPH total band activities, in their major sugar composition and in their hydroxymethylfurfural (HMF) content. It was found that, while all the assessed parameters changed over the monitoring period, changes were moderate at 40 °C but increased significantly with increasing temperature, especially the honeys' HPTLC-DPPH total band activity and HMF content.

Methods of the Dehydration Process and Its Effect on the Physicochemical Properties of Stingless Bee Honey: A Review

Stingless bee honey (SLBH) has a high moisture content, making it more prone to fermentation and leading to honey spoilage. Dehydration of SLBH after harvest is needed to reduce the moisture content. This review compiles the available data on the dehydration methods for SLBH and their effect on its physicochemical properties. This review discovered the dehydration process of vacuum drying at 60 °C and 5% moisture setting, freeze-drying at −54 °C and 5% moisture setting for 24 h, and using a food dehydrator at 55 °C for 18 h could extract >80% water content in SLBH. As a result, these methods could decrease moisture content to <17% and water activity to <0.6. These will prevent the fermentation process and microorganism growth. The hydroxymethylfurfural (HMF) contents remain within the permissible standard of <40 mg/kg. The total phenolic content increased after dehydration by these methods. Therefore, dehydration of SLBH is recommended to increase its benefits.

Pathophysiology of Depression: Stingless Bee Honey Promising as an Antidepressant

Depression is a debilitating psychiatric disorder impacting an individual’s quality of life. It is the most prevalent mental illness across all age categories, incurring huge socio-economic impacts. Most depression treatments currently focus on the elevation of neurotransmitters according to the monoamine hypothesis. Conventional treatments include tricyclic antidepressants (TCAs), norepinephrine–dopamine reuptake inhibitors (NDRIs), monoamine oxidase inhibitors (MAOIs), and serotonin reuptake inhibitors (SSRIs). Despite numerous pharmacological strategies utilising conventional drugs, the discovery of alternative medicines from natural products is a must for safer and beneficial brain supplement. About 30% of patients have been reported to show resistance to drug treatments coupled with functional impairment, poor quality of life, and suicidal ideation with a high relapse rate. Hence, there is an urgency for novel discoveries of safer and highly effective depression treatments. Stingless bee honey (SBH) has been proven to contain a high level of antioxidants compared to other types of honey. This is a comprehensive review of the potential use of SBH as a new candidate for antidepressants from the perspective of the monoamine, inflammatory and neurotrophin hypotheses.

Determination of 5-hydroxymethylfurfural using an electropolymerized molecularly imprinted polymer in combination with Salle

Coffee, a beverage with a complex chemical composition, is appreciated for the sensory experience of its taste and aroma. The compound 5-(hydroxymethyl)-2-furfural (HMF) is essential for sensory characterization of the beverage, and is also used in the traceability of its production. In this work, a procedure combining salting-out assisted liquid-liquid extraction (SALLE) and an electropolymerized molecularly imprinted polymer (e-MIP) was developed for the detection and quantification of HMF in coffee samples. The sample preparation step using SALLE employed a combination of acetonitrile and phosphate-buffered saline, in a proportion of 70:30 (ACN:PBS), with addition of 0.02 g of NaCl. The new sensor (e-MIP) was prepared by electropolymerization of p-aminobenzoic acid onto a glassy carbon electrode (GCE) using cyclic voltammetry (CV). Analytical determinations were performed by differential pulse voltammetry (DPV). The linear regression correlation coefficient (r²) for the response was 0.9986. The limits of detection and quantification were 0.372 mg L^-1 and 1.240 mg L^-1, respectively. The repeatability and reproducibility values obtained were 6 and 10%, respectively. The recoveries for three concentration levels were between 97 and 101%. Analyses of different coffee samples showed that the HMF concentrations varied from 261.0 ± 41.0 to 770.2 ± 55.9 mg kg^-1 in powdered coffee samples, and from 1510 ± 50 to 4445 ± 278 mg kg^-1 in instant coffee samples. The advantages of this procedure, compared to other methods described in the literature, are its simplicity, easy operation, good selectivity and sensitivity, low cost, and minimal use of organic solvents.

History and the immunostimulatory effects of heat-processed licorice root products with or without honey

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicine, the dried root of Glycyrrhiza uralensis Fisch. (licorice root) is usually used after stir-baked with honey. However, in Japanese traditional Kampo medicine, processed licorice root is prepared by roasting without honey.

AIM OF THE STUDY

We summarized our previous studies on the processed licorice root products to review the effectiveness of the processing for licorice root.

MATERIALS AND METHODS

We summarized our previous studies about processed licorice root. The first report was about investigating the successive literatures of traditional medicine in China and Japan about the processing of licorice root. Next was the report about chemically analyzing for prepared various kinds of processed licorice root samples. The last reports were evaluating in vitro effects of the extracts of these samples and heated honey on granulocyte colony-stimulating factor (G-CSF) secretion in cultured intestinal epithelial cells.

RESULTS

Before the Song dynasty in mainland China, the processing of licorice root for the internal usage had been roasted without any drug adjuvants. Then, clinicians had also used honey-roasted licorice to treat throat pain since the Song dynasty, and honey-roasted licorice has been used as the substitute to roasted licorice since the end of the Qing dynasty. While the descriptions using honey have been disappeared in 18th century in Japan. We found that the conversion between liquiritigenin and isoliquiritigenin or between liquiritin and isoliquiritin in licorice root by heating was accelerated by using honey as drug adjuvant. The inducible effect of G-CSF of licorice root was not augmented by roasting, but significantly augmented by stir-baked with honey. Heated honey also had this activity, and isomaltose contributed the appearance of this activity among the constituents in honey. The best activity was appeared when isomaltose was heated at 180 °C for 60 min or at 200 °C for 15-30 min, and the average molecular weight of the active product was 790 kDa.

CONCLUSIONS

By our previous studies, we believe that the processing method in China is better than that in Japan for licorice root, since the immunostimulatory effects are appeared in honey used as drug adjuvant when honey is heated. Among the ingredients of honey, isomaltose can be used as the marker compound to choose a conforming honey product for the processing of licorice root.

Quality Evaluation of Iranian Honey Collected from Khorasan Province, Iran

Honey is a prominent nutritional and medicinal production of honey bees, originating from the nectar of flowers. The physicochemical properties of honey serve as indicators of its freshness and originality. The current survey aimed to assess the parameters of quality control, including hydroxymethylfurfuraldehyde [HMF], reducing sugars, fructose/glucose, sucrose, proline content, distaste activity, and free acidity, in 25 honey samples of different brands available in Khorasan Province, Iran. We used the methods suggested by the Association of Official Analytical Collaboration (AOAC, 1995), the International Honey Commission (IHC, 2009), and the Codex Alimentarius Honey Standards for the study. Statistical analysis was performed in Microsoft Excel. The obtained data indicated that eight out of 25 analyzed samples (32%) complied with all the requirements and were generally of acceptable quality. Meanwhile, 17 samples (68%) were unconfirmed by the Iranian Standard Organization (ISO), including 12 samples with a low level of diastase (<8 Schade) and high levels of HMF (>15 mg/kg), two samples with high sucrose levels, two samples with high proline, and one sample with high HMF. These findings suggested their inappropriate storage (time/temperature), heat treatment, and/or adulteration with industrial sugar. According to the results, the examined honey samples produced in Khorasan Province were not of acceptable quality, which highlights the importance of an effective regulatory framework to be evaluated and rectified periodically and accurately to maintain consumer rights, as well as public health.

Conventional and emergent technologies for honey processing: A perspective on microbiological safety, bioactivity, and quality

Honey is a natural food of worldwide economic importance. Over the last decades, its potential for food, medical, cosmetical, and biotechnological applications has been widely explored. One of the major safety issues regarding such applications is its susceptibility to being contaminated with bacterial and fungi spores, including pathogenic ones, which may impose a hurdle to its consumption in a raw state. Another factor that makes this product particularly challenging relies on its high sugar content, which will lead to the formation of hydroxymethylfurfural (HMF) when heated (due to Maillard reactions). Moreover, honey's bioactivity is known to be affected when it goes through thermal processing due to its unstable and thermolabile components. Therefore, proper food processing methodologies are of utmost importance not only to ensure honey safety but also to provide a high-quality product with low content of HMF and preserved biological properties. As so, emerging food processing technologies have been employed to improve the safety and quality of raw honey, allowing, for example, to reduce/avoid the exposure time to high processing temperatures, with consequent impact on the formation of HMF. This review aims to gather the literature available regarding the use of conventional and emergent food processing technologies (both thermal and nonthermal food processing technologies) for honey decontamination, preservation/enhancement of honey biological activity, as well as the sensorial attributes.

Quality evaluation and geographical classification of immature rape and acacia honeys in China

BACKGROUND

To reflect and understand the real situation regarding immature honey, the quality parameters of 141 honey samples from different regions of China were evaluated. The possibility of classifying Chinese honey from different geographical origins was also considered.

RESULTS

The results revealed that the values of diastase, sucrose, proline and 5-hydroxymethylfurfural (HMF) met the international honey standard, although moisture, total glucose and fructose, and invertase content in most of the honey samples failed to meet the standards. In addition, honey from different geographical locations could be well separated based on the contents of maltose, sucrose, HMF and glucose oxidase.

CONCLUSION

The maturity of honey has a great impact on its quality, and the geographical origin of immature honey could be classified according to the physicochemical parameters. © 2021 Society of Chemical Industry.

Electro-oxidation and determination 5-hydroxymethylfurfural in food on co-electrodeposited Cu-Ni bimetallic microparticles modified copper electrode

This study presents a sensitive approach for electrochemical determination of 5-hydroxymethylfurfural (5-HMF) in food. The electrochemical sensor was fabricated on a copper electrode (CuE) modified with co-electrodeposited Cu-Ni bimetallic particles. This sensor, fabricated by 30 cycles of cyclic voltametric scanning with a scan rate of 50 mV s^-1, exhibits good electrocatalytic ability to 5-HMF oxidation. Under the optimal conditions, linear scan voltammetry (LSV) and chronoamperometry were conducted for the determination of 5-HMF. The results of LSV show that a linear dependency within the 0.4-10 mM range with a detection limit (LOD) of 3.51 μM (S/N = 3) was achieved, while a linear range in 1 × 10-⁴-11 mM with a LOD of 0.043 μM (S/N = 3) was obtained by chronoamperometric measurement. The electrochemical sensor was finally applied in determination of 5-HMF in various foods, and the reliability and accuracy of the method were assessed by adopting an UV method as a standard method. Results show that the concentrations of 5-HMF in real samples are close to those measured by the standard method. In addition, standard addition method was further performed to evaluate the accuracy of our approach. The recoveries ranged from 90.0% to 110.0% are calculated, demonstrating good accuracy of the electrochemical sensor.

Characterization of honeys produced by sympatric species of Afrotropical stingless bees (Hymenoptera, Meliponini)

We investigated the effect of bee species identity and harvesting methods on the chemical composition and antiradical activity of 53 honey samples, produced by six stingless bee species in western Kenya (Kakamega forest). Our results illustrate that none of the assayed parameters significantly varied between the honey samples harvested by "punching holes" (n = 25) and "squeezing" (n = 28) methods. By contrast, species identity drove significant differences in the assayed parameters. Positive correlations between the antiradical activity and the phytochemicals (phenols and flavonoids) were observed, and honeys from Liotrigona sp. exhibited the highest amounts of phenols (214 mg GAE/100 g), flavonoids (73.0 mg QE/100 g) and antiradical activity (76.2%). The physicochemical analyses confirm the need to establish separate stingless bee honey standards for moisture, free acidity, invertase, electrical conductivity, and HMF, as these parameters significantly diverged from the set limits for Apis mellifera honey.

The stingless bee honey protects against hydrogen peroxide-induced oxidative damage and lipopolysaccharide-induced inflammation in vitro

Oxidative stress, DNA damage, and unresolved inflammation are the predisposing factors of many chronic and degenerative diseases, including cancer. Stingless bee honey (SBH) is recognized to have high medicinal value by traditional medicine practitioners and has been used to treat various illnesses traditionally. This study aimed to determine the antioxidant, anti-inflammatory, and genoprotective effects of SBH by using in vitro cell culture models. The sugar content, total phenolic content, radical scavenging activity, and ferric reducing antioxidant power (FRAP) of SBH were determined in this study. Then, the protective effect of SBH against hydrogen peroxide (H₂O₂)-induced cell death and DNA damage was studied by using WIL2-NS human lymphoblastoid cell line, while the lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages cell line was used to study the anti-inflammatory effects of SBH. Results from this present study showed that the major sugar contents of SBH were fructose (19.39 + 0.01%) and glucose (14.03 ± 0.03%). Besides, the total phenolic content, the radical scavenging activity, and the FRAP value of SBH were 15.38 ± 0.02 mg GAE/100 g of honey, 34.04 ± 0.21%, and 206.77 + 1.76 μM AAE/100 g honey respectively. Pretreatment with SBH protected WIL2-NS cells from H₂O₂-induced cell death and DNA damage (p < 0.001). Moreover, SBH was also able to attenuate the production of nitric oxide by inhibiting the expression of inducible nitric oxide synthase in LPS-induced RAW 264.7 cells (p < 0.001). In conclusion, SBH is rich in total phenolic content and possesses strong antioxidant, anti-inflammatory, and genoprotective properties. Our current findings suggest that SBH might be useful in the prevention and treatment of many diseases caused by oxidative stress and inflammation assuming the observed effects are also achievable in vivo.

A sensitive and visual molecularly imprinted fluorescent sensor incorporating CaF2 quantum dots and β-cyclodextrins for 5-hydroxymethylfurfural detection

Calcium fluoride (CaF₂) quantum dots have many applications in various fields. But there is no report on fluorescent characteristics of CaF₂ quantum dots (CaF₂ QDs). Here, a synthesis of multiple-color emission CaF₂ QDs by changing the temperature, time and raw ratio is reported, by which the CaF₂ QDs with purple, blue, green, and yellow emission can be obtained, respectively. They were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). On this basis, a novel molecular imprinting ratiometric fluorescence sensor (MIR sensor) had been constructed based on the prepared CaF₂ QDs and CdTe QDs, in which the yellow emission CaF₂ QDs was used as a responsive signal material and the red emission CdTe QDs was served as a reference signal material. And the β-CD and methylacrylic acid (MAA) as bifunctional monomers were used for constructing the specific molecularly imprinted polymers (MIPs) in MIR sensor. This MIR sensor was applied for highly selective and excellent sensitive detection of 5-hydroxymethylfurfural (HMF). Under optimum conditions, it exhibited an excellent linear relationship between the fluorescence intensity ratio (I₅₉₉/I₆₂₅) and the concentration of HMF in the range of 0.1-6.0 μg/mL with a detection limit of 0.043 μg/mL. Finally, the established HMF-MIR sensor was successfully utilized to detect HMF in honey with satisfactory results. This work provided a reference for the application of the CaF₂ QDs and the detection of the furfural substances.

The Toxicological Aspects of the Heat-Borne Toxicant 5-Hydroxymethylfurfural in Animals: A Review

The incidence of adverse reactions in food is very low, however, some food products contain toxins formed naturally due to their handling, processing and storage conditions. 5-(Hydroxymethyl)-2-furfural (HMF) can be formed by hydrogenation of sugar substances in some of manufactured foodstuffs and honey under elevated temperatures and reduced pH conditions following Maillard reactions. In previous studies, it was found that HMF was responsible for harmful (mutagenic, genotoxic, cytotoxic and enzyme inhibitory) effects on human health. HMF occurs in a wide variety of food products like dried fruit, juice, caramel products, coffee, bakery, malt and vinegar. The formation of HMF is not only an indicator of food storage conditions and quality, but HMF could also be used as an indicator of the potential occurrence of contamination during heat-processing of some food products such as coffee, milk, honey and processed fruits. This review focuses on HMF formation and summarizes the adverse effects of HMF on human health.

Stingless Bee Honey Improves Spatial Memory in Mice, Probably Associated with Brain-Derived Neurotrophic Factor (BDNF) and Inositol 1,4,5-Triphosphate Receptor Type 1 (Itpr1) Genes

This study was conducted to evaluate the effects of stingless bee honey (SBH) supplementation on memory and learning in mice. Despite many studies that show the benefits of honey on memory, reports on the nootropic effects of SBH are still lacking, and their underlying mechanism is still unclear. SBH is a honey produced by the bees in the tribe of Meliponini that exist in tropical countries. It features unique storage of honey collected in cerumen pots made of propolis. This SBH may offer a better prospect for therapeutic performance as the previous report identifies the presence of antioxidants that were greater than other honey produced by Apis sp. In this study, SBH was tested on Swiss albino mice following acute (7 days) and semichronic (35 days) supplementation. Experiments were then conducted using Morris water maze (MWM) behaviour analysis, RT-PCR for gene expression of mice striatum, and NMR for metabolomics analysis of the honey. Results indicate spatial working memory and spatial reference memory of mice were significantly improved in the honey-treated group compared with the control group. Improved memory consolidations were also observed in prolonged supplementation. Gene expression analyses of acutely treated mice demonstrated significant upregulation of BDNF and Itpr1 genes that involve in synaptic function. NMR analysis also identified phenylalanine, an essential precursor for tyrosine that plays a role at the BDNF receptor. In conclusion, SBH supplementation for seven days at 2000 mg/kg, which is equivalent to a human dose of 162 mg/kg, showed strong capabilities to improve spatial working memory. And prolonged intake up to 35 days increased spatial reference memory in the mice model. The phenylalanine in SBH may have triggered the upregulation of BDNF genes in honey-treated mice and improved their spatial memory performance.

Inhibitory Effect of Hydroxymethylfurfural in Viability of BALB/C Mice Splenocytes

Background: This study was designed to discover if hydroxymethylfurfural (HMF) exposure modifies cell proliferation and DNA damage in BALB/c mice splenocytes. Methods: Mitogenesis in T cells and B cells was induced by Concanavalin A (Con A) and lipopolysaccharide (LPS). The colorimetric tetrazolium assay was used to evaluate cell proliferation. DNA damaging consequences were evaluated via measurement of 8-hydroxy-2-deoxyguanosine (8-OHdG) level in BALB/c mice splenocytes. Results: Spleen cells proliferation elicited by ConA, was dramatically suppressed by 25, 50 and 100 mM of HMF. However, there was not any significant difference between various concentrations of HMF. The same result was observed following treatment with LPS and HMF in different concentrations. Eight-OHdG concentration was elevated significantly in HMF treated groups compared with untreated control and mitogens. Conclusion: HMF was found to have immunosuppressing and DNA damaging properties in mM concentrations in mice splenocytes.

Influence of honey types and heating treatment on the rheological properties of glutinous rice flour gels

Present study compared the rheological properties of glutinous rice flour (GRF) gel (33.3%, w/v) added with raw bee honey (RBH) or stingless bee honey (SBH) with/without heating treatment. RBH (diatase activity: 12.14 Schade) and SBH (1.53 Schade) significantly reduced the network of GRF gel by lowering the gel viscosity, with RBH having the highest rate of viscosity decrease (- 2.74 × 10^-5 Pa). As the addition of heated-SBH or heated-RBH did not reduce gel viscosity, it was hypothesised that active diastase played a major role to weaken gel network. This was further supported by the significant and the lowest storage modulus (G') value of RBH-GRF gel (5.99 ± 0.02 Pa), as compared to SBH-GRF (6.27 ± 0.04 Pa) and control (6.33 ± 0.04 Pa). A detail of rheological behaviour of the gels was further explained using power law. Overall, this GRF gel model has successfully demonstrated the potential of honey diastase in weakening network of starch-based food.

The Effect of Kelulut Honey on Fasting Blood Glucose and Metabolic Parameters in Patients with Impaired Fasting Glucose

Background

Impaired fasting glucose (IFG) poses a higher risk of diabetes. Honey has been reported to improve metabolic abnormalities including lowering hyperglycemia. This study is sought at determining the effect of Malaysian Kelulut honey (KH) on fasting glucose levels and metabolic parameters in IFG patients.

Methods

This quasi-experimental intervention study of 30-day duration was conducted among 60 adult patients with IFG. They were allocated into taking 30 g/day KH group (experimental group, n=30) and not taking KH group (control group, n=30). Body mass index (BMI), waist circumference, blood pressure (BP), fasting glucose, and lipid profile levels (total cholesterol, triglyceride, high-density lipoprotein, and low-density lipoprotein) were measured before and after treatment.

Results

There was no significant difference in all measured variables at day 30 compared to day 1 within both groups. Similarly, all measured variables neither at day 1 nor at day 30 had shown a statistically significant difference between the groups.

Conclusions

Daily intake of 30 g KH for 30 days resulted in insignificant effect on fasting glucose, fasting lipid profiles, and other metabolic parameters in patients with IFG. Further studies that employ longer study duration are needed to ascertain the finding.

The immunostimulatory effects and chemical characteristics of heated honey

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicine (TCM), honey has been used as an additive in the heat-processing of herbal medicines to enhance their immunostimulatory activities.

AIM OF THE STUDY

We investigated the immunostimulatory activity of heated honey in vitro and in vivo.

MATERIALS AND METHODS

For the in vitro study, we compared the differences among the inducible effects of honey subjected to various heating conditions on granulocyte colony-stimulating factor (G-CSF) secretion from the cultured enterocytes and investigated the active ingredient. For the in vivo study, we conducted a survival test of mice infected by Streptococcus pyogenes with and without oral administration of heated honey.

RESULTS

We found that heating the honey induced the appearance of G-CSF secretions from the cultured enterocytes, and that this appearance depended on the heating temperature and time. No G-CSF secretions appeared when honey was not heated. Mice infected with Streptococcus pyogenes that were fed heated honey revealed prolonged survival. The active ingredient in heated honey was a high-molecular compound with about 730 kDa. When this compound was hydrolyzed, galactose, glucose, rhamnose, α-ribofuranose β-ribofuranose 1,5':1',5-dianhydride, and 5-hydroxymethylfurfural were generated.

CONCLUSIONS

Heated honey reveals immunostimulatory activity both in vitro and in vivo. These results support the scientific evidences of the TCM theory.