Factors Affecting the Physicochemical Properties and Chemical Composition of Bee’s Honey

Exploring formation of turanose in honey via stable isotope labelling and high-resolution mass spectrometry analysis

Turanose, an isomer of sucrose, naturally exists in honey. Previous study indicated that turanose content increased gradually in acacia honey as honeybees brewed honey in the hive. However, it is unclear how turanose is generated in honey. We hypothesised that turanose was produced by enzymes from honeybees and performed a series of simulation experiments to prove this hypothesis. We found turanose in honey was produced by honeybees processing sucrose. Furthermore, we determined that sugar composition of simulated nectar influenced the turanose concentration in honey: when sucrose concentration was below 5%, turanose was difficult to form, whereas high concentration of fructose and limited glucose were beneficial in producing turanose. Using 13C-labelled sucrose tests combined with proteomics analysis, we identified that α-glucosidase converted sucrose to turanose through an intermolecular isomerisation process. This study reveals the formation mechanism of turanose in honey and assists in the scientific control and improvement of honey quality.

Pesticide residues in traditional and industrial honey marketed in Morocco and potential health risk

This study evaluated the presence of the three pesticides methomyl (MET), carbendazim (CBZ) and chlorpyrifos-ethyl (CPE), as well as the degradation product of CPE (3,5,6-trichloro-2-pyridinol; TCP), in 44 honey samples from all 12 regions of Morocco. With a validated HPLC-UV method occurrence frequencies of 63.6% for MET, 54.5% for CBZ, 95.1% for CPE and 34.1% for TCP were obtained, even at concentrations higher than the maximum residue limits for MET, CPE and TCP. Based on the predominant pesticide, principal component analysis separated sampling regions into three groups. Risk assessment indicated that ingestion of these pesticides, alone or in combination, in honey did not pose a risk to consumers (HQ and HI < 1).

Impact of floral and geographical origins on honey quality parameters in Saudi Arabian regions

This article examined the effect of geographical (different climate conditions) and floral origins on some quality parameters of honey including the activity of diastase enzyme. Moreover, some non-quality parameters were investigated such as the pH, fructose, glucose, ratio of fructose/glucose and invertase. The honey samples were collected from Asir (cold climate) and Jazan (hot climate) regions at the southwestern part of Saudi Arabia. The geographical origin significantly affected the mean value moisture of the Acacia honey (p-value = 0.02), conductivity of the polyfloral honey (p-value = 0.03), sucrose of the Acacia honey (p-value = 0.02), diastase activity of the Acacia (p-value = 0.001), Ziziphus (p-value = 0.046) and polyfloral honey (p-value ≤ 0.001), fructose of the Acacia honey (p-value = 0.01), glucose of the Ziziphus honey (p-value = 0.03), fructose/ glucose ratio of the Ziziphus honey (p-value = 0.035), and invertase activity of the polyfloral honey (p-value ≤ 0.001). Regarding the effect of the floral origin of the honey from Asir region, the sucrose percentage of the Acacia honey was significantly more than that of the polyfloral honey (p- value = 0.003), the diastase activity of the Acacia honey was significantly more than its activity in the Ziziphus honey (p- value = 0.044), glucose percentage of the Ziziphus honey was significantly more the glucose percentage of the Acacia honey (p-value = 0.009) and the fructose/ glucose ratio of the Ziziphus honey was significantly more than that of the Acacia and polyforal honeys (p-value = 0.011 and p-value = 0.045, respectively). Concerning the significant effects of the floral origin on the quality parameters of the honey samples from Jazan region, the moisture of the Ziziphus honey was significantly increased when compared to the moisture of the Acacia honey (p-value = 0.038), the acidity of the polfloral honey was significantly more than the acidity of the Acacia honey (p-value = 0.049), the sum of fructose and glucose of the polyfloral honey was significantly increased compared to that of the Acacia honey (p-value = 0.015), the pH of the Ziziphus hiney was significantly more than the pH of the polyfloral honey (0.011) and the fructose of the polfloral honey was significantly more than that of the Acacia honey (p-value = 0.031). The effect of the geographical origin of the honey samples on their quality parameters depends on their floral origin and the effect of their floral origin differs according to their geographical origin. This article suggests considering collectively the geographical and floral origins effect when developing honey standards. However, the Codex standards for honey started considering this issue when it changed the standard concentration of HMF in honey from not more than 80-40 mg/Kg for honeys from cold climate and 80 mg/Kg for honeys from hot climates.

The quality of selected raw and pasteurized honeys based on their sensory profiles and consumer preferences

The purpose of this study was to determine the sensory profile of honeys based on the method of quantitative descriptive analysis and principal component analysis and assess consumer preferences of raw and pasteurized honeys. Samples of multi-floral honeys (from the store and apiary) were subjected to sensory analysis based on the method of ranking for taste preference, the method of scaling based on color, aroma, taste, and texture, and the method of differential descriptive analysis using 11 quality descriptors. The results were subjected to statistical analysis using the Principal Component Analysis method. The taste was found to be a descriptor that differentiates honey by origin. Consumers prefer the taste of pasteurized honeys. As a result of assessing the quality of honeys using the scaling method, it was found that: raw honeys are characterized by a lighter color than pasteurized honeys, store-bought honeys have a less noticeable aroma than honeys obtained from beekeepers, while samples of pasteurized honeys were judged to have a consistency more like that of typical honey. The sensory profiles obtained highlight the differences between pasteurized honeys and raw honeys.

Fingerprinting Chemical Markers in the Mediterranean Orange Blossom Honey: UHPLC-HRMS Metabolomics Study Integrating Melissopalynological Analysis, GC-MS and HPLC-PDA-ESI/MS

(1) Background: Citrus honey constitutes a unique monofloral honey characterized by a distinctive aroma and unique taste. The non-targeted chemical analysis can provide pivotal information on chemical markers that differentiate honey based on its geographical and botanical origin. (2) Methods: Within the PRIMA project "PLANT-B", a metabolomics workflow was established to unveil potential chemical markers of orange blossom honey produced in case study areas of Egypt, Italy, and Greece. In some of these areas, aromatic medicinal plants were cultivated to enhance biodiversity and attract pollinators. The non-targeted chemical analysis and metabolomics were conducted using ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). (3) Results: Forty compounds were disclosed as potential chemical markers, enabling the differentiation of the three orange blossom honeys according to geographical origin. Italian honey showed a preponderance of flavonoids, while in Greek honey, terpenoids and iridoids were more abundant than flavonoids, except for hesperidin. In Egyptian honey, suberic acid and a fatty acid ester derivative emerged as chemical markers. New, for honey, furan derivatives were identified using GC-MS in Greek samples. (4) Conclusions: The application of UHPLC-HRMS metabolomics combined with an elaborate melissopalynological analysis managed to unveil several potential markers of Mediterranean citrus honey potentially associated with citrus crop varieties and the local indigenous flora.

Honey characterization and identification of fructophilic lactic acid bacteria of fresh samples from Melipona beecheii, Scaptotrigona pectoralis, Plebeia llorentei, and Plebeia jatiformis hives

Stingless bees are essential to preser tropical ecosystems. They pollinate native flora, producing honey with properties for traditional health uses. Lactic acid bacteria spontaneously ferment honey in stingless bee honey (SBH). This study aims to determine the main physicochemical characteristics of Melipona beecheii, Scraptotrigona pectoralis, Plebeia jatiformis and Plebeia llorentei honey and to isolate and identify FLAB present in SBH samples. The physicochemical properties of SBH, such as color, pH, acidity, sugars, protein, total soluble solids, water activity, total polyphenols, and antioxidant activity, were determined since these parameters can be related to the presence of some bacteria groups, and with health benefits for humans and the hive ecosystems. FLAB harvested from honey, taken directly from storing pots of the hives, were identified by 16S ribosomal RNA sequencing and preserved for future biotechnological use due to their resistance to non-ionic osmotic stress. The results showed significant differences in the physicochemical characteristics of SBH samples. Seven FLAB from four stingless bee species were identified as Fructobacillus pseudoficulneus and F. tropaeoli. In addition, three other strains of Fructilactobacillus spp. were identified only at the genus level. All species showed the ability to grow under different carbon sources, resulting in negative hemolysis and sensitivity to cefuroxime, erythromycin, and chloramphenicol. To the best of our knowledge, this is the first time that the physicochemical and FLAB characterization of SBH from P. jatiformis and P. llorentei has been reported. Therefore, the future following research should be focused on the environmental, health and food biotechnological applications implications of FLAB from SBH.

Characterization of Various Honey Samples from Different Regions of Morocco Using Physicochemical Parameters, Minerals Content, Antioxidant Properties, and Honey-Specific Protein Pattern

Honey is a bee product relatively expensive; therefore, it has been a target of adulteration by many sweeteners. In this work, we evaluated the good quality, authenticity, and content in bioactive molecules of twenty-two Moroccan honey from different botanical origins and geographical areas. For that, the following analyses were determined: the content in total protein and especially the major royal jelly protein (apalbumin 1), the analysis of total acidity, free acidity, lactonic acidity, pH, ash, Pfund, electrical conductivity, and moisture. In addition, the content of sodium, potassium, calcium, and magnesium, the dosage of polyphenols, flavones, and flavonols, and the antioxidant activities were assessed. All analyzed samples had good antioxidant activities and present a source of antioxidant compounds, the predominant mineral in all honey samples was potassium, and the physicochemical parameters are in line with the standards’ recommended limits. The content of honey samples in total protein and apalbumin 1 ranged between 212 μg/g and 4121.2 μg/g and between 27.4 μg/g and 790.82 μg/g, respectively. Overall, the detection of apalbumin 1 in all honey samples and the results of physicochemical parameters, minerals, bioactive compounds, and antioxidant activities confirm the authenticity and no adulteration of Moroccan honey.

Glucose Oxidase and Catalase Activities in Honey Samples from the Southwestern Region of Saudi Arabia

The activity of honey enzymes are affected by floral and geographical origins, climate conditions, honeybee species, health and nutrition. This article investigated the effect of floral and geographical origins on the activity of glucose oxidase (GOx) and catalase (CAT) enzymes in honey samples from the southwestern region of Saudi Arabia. Moreover, the moisture, total sugars, pH and conductivity were measured as quality parameters. The floral origin of the honey samples was determined microscopically while the quality parameters were measured according to the methods of international honey commission. The activity of the honey enzyme was determined following the instructions of the Megazyme International kits. The obtained results were statistically analyzed by the statistical Package for Social Sciences (SPSS, v.20). The GOx activity of the Acacia, Ziziphus and polyfloral honey samples of the Asir region were (5.19 ± 2.33 U/g), (4.01 ± 1.17 U/g) and (5.69 ± 1.67 U/g), respectively. The Acacia, Ziziphus and polyfloral honey samples from the Jazan region had GOx activities of (6.85 ± 0.47 U/g), (10.48 ± 9.22 U/g) and (5.31 ± 2.7 U/g), respectively. The geographical origin significantly affected the GOx activity of Ziziphus honey (p-value = 0.005) and the GOx activity of the Ziziphus honey was significantly more than that of the polyfloral honey of the Jazan region (p-value = 0.009). With regard to the CAT activity in Asir region honey samples, the mean values of the Acacia, Ziziphus and polyfloral honeys were (2.89 ± 1.08 U/g), (3.58 ± 1.59 U/g) and (2.84 ± 1.24 U/g), respectively. The mean values of the CAT activity in the Jazan honey samples were Acacia (4.35 ± 1.01 U/g), Ziziphus (3.94 ± 0.04 U/g) and polyfloral (3.43 ± 0.67 U/g). The geographical origin significantly affected the CAT activity in Acacia honey (p-value = 0.014). The geographical and floral origins had significant effects on the activity of the honey GOx and CAT enzymes.

Identification of Pigmented Substances in Black Honey from Leucosceptrum canum: Novel Quinonoids Contribute to Honey Color

Leucosceptrum canum (Lamiaceae) honey (LCH) is a rare and high-value honey with an unusual dark brown color. Its pigments may be related to the purported health benefits of the honey and could serve as indicators of authentic LCH. Here, we purified the pigmented substances contributing to LCH's color and identified them using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. The major pigmented substances were 1-[4-(3-carboxy-propylamino)-3,6-dioxo-cyclohexa-1,4-dienyl]-pyrrolidine-2-carboxylic acid (GPBQ), 1-[4-(3-carboxy-propylamino)-3,6-dioxo-cyclohexa-1,4-dienyl]-pyrrolidine-2-carboxylic acid. (GAPBQ), and 2,5-di-(N-prolyl)-para-benzoquinone (DPBQ). According to UHPLC-DAD data recorded at 370 nm, GPBQ, GAPBQ, and DPBQ contents ranged from 2.58 to 5.13, 2.93 to 4.96, and 4.26 to 9.22 mg/kg, respectively. These amino acid-quinone conjugates, found here for the first time, are pigments that can serve as markers to control the quality of LCH.

Investigation of the Maturity Evaluation Indicator of Honey in Natural Ripening Process: The Case of Rape Honey

Honey maturity, a critical factor for quality evaluation, is difficult to detect in the current industry research. The objective of this study was to explore the changes in the composition and find potential maturity indicators of rape honey at different maturity stages through evaluating physicochemical parameters (moisture, sugars, pH, electrical conductivity, total protein, total phenols, total flavonoids, proline, and enzyme activity), the antioxidant capacity, and volatile components. The relevant results are as follows: 1. As the maturity increased, the moisture, sucrose, and maltose content of rape honey gradually decreased, while the glucose, fructose, and total protein content gradually increased. The activities of diastase, invertase, and β-glucosidase showed a significant increase with the elevation of ripening days, and the activity of glucose oxidase reached the highest before completely capping. 2. The antioxidant capacity of honey increased with the increase in honey maturity. There is a significant and strong correlation between the bioactive components of rape honey and antioxidant capacity (p < 0.01, |r| > 0.857). 3. Thirty-five volatile components have been identified. Nonanal, benzaldehyde monomer, and benzaldehyde dimer can be used as potential indicators for the identification of honey maturity stages. Principal component analysis (PCA) based on antioxidant parameters and volatile components can identify the maturity of honey.

Chemical Analyses and Antimicrobial Activity of Nine Kinds of Unifloral Chinese Honeys Compared to Manuka Honey (12+ and 20+)

Honey has good antimicrobial properties and can be used for medical treatment. The antimicrobial properties of unifloral honey varieties are different. In this study, we evaluated the antimicrobial and antioxidant activities of nine kinds of Chinese monofloral honeys. In addition, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) technology was used to detect their volatile components. The relevant results are as follows: 1. The agar diffusion test showed that the diameter of inhibition zone against Staphylococcus aureus of Fennel honey (21.50 ± 0.41 mm), Agastache honey (20.74 ± 0.37 mm), and Pomegranate honey (18.16 ± 0.11 mm) was larger than that of Manuka 12+ honey (14.27 ± 0.10 mm) and Manuka 20+ honey (16.52 ± 0.12 mm). The antimicrobial activity of Chinese honey depends on hydrogen peroxide. 2. The total antioxidant capacity of Fennel honey, Agastache honey, and Pomegranate honey was higher than that of other Chinese honeys. There was a significant positive correlation between the total antioxidant capacity and the total phenol content of Chinese honey (r = 0.958). The correlation coefficient between the chroma value of Chinese honey and the total antioxidant and the diameter of inhibition zone was 0.940 and 0.746, respectively. The analyzed dark honeys had better antimicrobial and antioxidant activities. 3. There were significant differences in volatile components among Fennel honey, Agastache honey, Pomegranate honey, and Manuka honey. Hexanal-D and Heptanol were the characteristic components of Fennel honey and Pomegranate honey, respectively. Ethyl 2-methylbutyrate and 3-methylpentanoic acids were the unique compounds of Agastache honey. The flavor fingerprints of the honey samples from different plants can be successfully built using HS-GC-IMS and principal component analysis (PCA) based on their volatile compounds. Fennel honey, Agastache honey, and Pomegranate honey are Chinese honey varieties with excellent antimicrobial properties, and have the potential to be developed into medical grade honey.