Physicochemical parameters of Bulgarian monofloral rape and lime honeys

Abstract. Larbi DA, Klutse CK, Adotey DK. 2022. Gamma irradiation effect on the microbial load and physicochemical properties of honey from Ghana. Cell Biol Dev 6: 94-107. The honey's high sugar concentration and low pH give it antimicrobial properties and make it difficult for microorganisms to grow. This study is to ascertain microorganisms' presence in Ghanaian honey, the sources of microbial contamination, the physico-chemical properties of honey, and the effect of gamma radiation on the microbial load. Furthermore, 90 honey samples were collected from Brong Ahafo, Ashanti, and Greater Accra, Ghana, with 30 from each region. Honey was sampled directly from the beehive with the comb before the farmer harvested, and honey was sampled from retailers who buy directly from the farmer. The effect of gamma radiation on the microbial load was studied using a 60Co source gamma irradiation facility at doses of 20 kGy, 30 kGy, and 40 kGy on the presence of microbes and the physicochemical properties (pH, reducing sugar, apparent sucrose, and ash content) of honey. The pH values obtained for the Honey Comb samples were in the range of 3.6-3.9, and the pH for the Retail samples was in the range of 4.9-5.6. Microorganisms were not detected in about 70% of the honey sampled directly from the honeycomb. The mean microbial count in the remaining 30% was within the range of 30-35%, whereas all the honey sampled from the retailers was contaminated with microbes. The mean microbial counts in the retailer samples were 148 CFU/g, 183 CFU/g, and 271 CFU/g for Ashanti, Brong Ahafo, and Greater Accra Regions, respectively. These values were significantly higher than the required maximum relative to the MERCOSUR (Mercado Comun del SUR) standard (? 100 CFU/g). The low level of microbial detection in the Honey Comb samples (30-35 CFU/g) could be due to their relatively low pH levels (3.6-3.9) compared to the retailer samples with pH within 4.9-5.6. The ash content of all the honey sampled and analyzed was within the required standard, with an average of 0.16% in the honeycomb samples and an average of 0.62% for the retail samples. The apparent sucrose concentration (in percentage) in honey sampled from the retailers was within the range of 22-33%, which is beyond the required maximum as stipulated by the CODEX Alimentarius Commission (? 10%). The study showed that a 20 kGy gamma radiation dose was enough to denature the microbes and preserve the honey's essential qualities. Finally, to ensure good quality honey on the Ghanaian market, it is recommended that honey meant for human consumption should undergo gamma irradiation (cold pasteurization).

A novel methodology for real-time identification of the botanical origins and adulteration of honey by rapid evaporative ionization mass spectrometry

Floral classification of honey using liquid chromatography–diode array detection–tandem mass spectrometry and chemometric analysis

FTIR-ATR spectroscopy of pollen and honey as a tool for unifloral honey authentication. The case study of rape honey

The purpose of the work was to compare the quality of selected honey available on the Polish market, including traditional (rape, lime and meadow and marsh honey) and non-traditional honey (lime, buckwheat, and honeydew honey from coniferous honeydew). Parameters such as electrical conductivity, color, pH, acidity, water, hydroxymethylfurfural, total phenols content, and ability to deactivate ABTS cation radicals were determined. The profile of aroma compounds was carried out by GC-MS technique, and determination of sugars was performed by HPLC. It was found that all tested honey met standards according to European law requirements. Semi-quantitative analysis of volatile compounds showed that all honey samples contain numerous volatiles (in buckwheat honey there were 67 compounds, and in honeydew honey from coniferous honeydew, only 40 compounds). Characteristic volatile compounds of each aroma profile were described e.g., benzaldehyde, acetone, 2-methyl-butanal, nonanal, benzyl alcohol were found in rape honey aroma, and furfural, isovaleric acid, ethanol, delta-valerolactone, isovaleraldehyde, 2-methyl-butanoic acid, and phenylacetaldehyde in buckwheat honey aroma. The total content of volatiles was the highest in buckwheat honey (199.62 µg/kg), and in traditional lime honey (195.17 µg/kg). The lowest total content of volatile substances was established in non-traditional lime honey (73.20 µg/kg) and in rape honey (39.52 µg/kg).

Application of ICP-MS method of determination of 15 elements in honey with chemometric approach for the verification of their authenticity

Characterization of Polish rape and honeydew honey according to their mineral contents using ICP-MS and F-AAS/AES

The objective of this study was to establish a real-time LAMP assay for authentication of rape (Brassica napus) honey to protect consumers from commercial honey adulteration. The LAMP primers targeting the internal transcribed spacer (ITS) of Brassica napus were designed, and its specificity was tested. The LAMP reaction temperature was also optimized, and the detection limit of the LAMP assay was determined with a serial dilution of genomic DNA from the seeds of Brassica napus. The results showed that the real-time LAMP assay can accurately and specifically detect the rape component in honey, and the detection limit was 10 pg genomic DNA of Brassica napus. Data on monofloral honey samples indicate that the real-time LAMP assay was 100% in concordance with the reported TaqManTM PCR assay. This study provides a promising solution for facilitating the authentication of rape honey in food retail market.

The aim of the study was to analyze the fresh honey after extracting and after half-year storage at room temperature. Overall, we analyzed 10 samples of rape (Brassica napus) honey coming from district Vranov nad Toplou located in the eastern Slovakia. The analysis consisted of the evaluation of the physico-chemical parameters (water content, free acidity and electrical conductivity) and microbiological evaluation (total plate count (TPC), counts of coliform bacteria, lactic acid bacteria, sporulating microorganisms and microscopic fungi). Water content, free acidity and electrical conductivity were measured according to IHC (2009), namely these parameters were detected by refractometer, titration and conductometer, respectively. We used dilution plating method for microbiological analysis. Fresh rape honey contained 18.3 ±1.0% of water. Free acidity of fresh rape honey was 12.7 ±2.0 meq.kg-1 and electrical conductivity was 0.14 mS.cm-1. After half a year of storage, water content and electrical conductivity decreased nonsignificantly and free acidity increased nonsignificantly. Stored honey samples meet the requirements of Decree 41/2012 and 106/2012. From microbiological point of view, fresh rape honey showed relatively high microbial counts. Mean values of TPC, sporulating microorganisms, lactic acid bacteria and yeasts exceeded 2.00 log cfu/g. All spotted microbial groups decreased in the stored honey comparing with the fresh honey. We found significant (p ˂0.01) differences of TPC, lactic acid bacteria and yeasts comparing the fresh and stored honey samples. Evaluating microbiological parameters, one sample of stored honey did not meet the requirements of Codex Alimentarius SR (2014). TPC exceeded the limit value. Based on the results we can conclude that all samples meet the requirements for good quality honey. Microbial counts in the honey decreased gradually. Probably, various microorganisms have important role in creation of the honey from the nectar of plants, but non-sporulating microorganisms die in the ripe honey.

Classification of acacia, rape and multifloral Hungarian honey types

Honey contains important bioactive compounds (enzymes, phenolic compounds, vitamins, and minerals) with several positive health effects for humans. In the study six types of honey (acacia, rape, floral, multi flower, forest, and honeydew honeys), of Czech and Slovak origin, were evaluated for bioactive compounds by means of color, polyphenols and antioxidant capacity analyses. The brightest color of honeys, the lowest values measured spectometrically, had acacia and rape honeys, followed by floral, and darker multi flower and forest honeys, and honeydew honeys. Polyphenols (PP) amount, determined by spectrophotometric method with Folin-Ciocalteu reagent, was highest for the darkest honeydew honeys, followed by multi flower and forest honey, brighter floral honeys, and rape and acacia honey. Honeys polyphenols were in the range from 54.0 to 254.2 mg GAE.100g-1. The total antioxidant capacity (TAC) was analyzed by spectrometric methods with ABTS and DPPH reagents. Antioxidant capacity values are in agreement with the PP contents order. They were highest also for honeydew honeys (59.2 - 89.6 and 73.1 - 118.7 mg TE.100g-1), followed by multi flower (66.0 and 56.7 mg TE.100g-1) and forest honey (56.0 and 49.1 mg TE.100g-1), then floral honeys (33.0 - 49.2 and 27.8 - 38.7 mg TE.100g-1) and the lowest values for rape (19.0 and 28.1 mg TE.100g-1) and acacia (15.5 and 11.3 mg TE.100g-1)honey. A positive correlation between color, PP amount and TAC was evaluated for analyzed honeys. Darker honey samples showed higher values of phenolic compounds and antioxidant potential, therefore they belong to the honey types with higher amount of bioactive compounds such as antioxidants.

Honey fraud has an extensive global magnitude and impacts both honey price and beekeeper viability. This study aimed at investigating the characteristic phytochemicals of rape, acacia, and linden honey to verify honey authenticity. We discovered methyl syringate, phaseic acid, and lindenin (4-(2-hydroxypropan-2-yl) cyclohexa-1,3-diene-1-carboxylic acid) as particular or unique phytochemicals of rape, acacia, and linden honey. Methyl syringate and lindenin were the most abundant components in rape and linden honey; moreover, their average contents reached up to 10.44 and 21.25 mg/kg, respectively. The average content of phaseic acid was 0.63 mg/kg in acacia honey. To our knowledge, the presence of phaseic acid in honey is a novel finding. Furthermore, we established the HPLC fingerprints of three monofloral honeys. We offered assessment criteria and combined characteristic components with standard fingerprints to evaluate the authenticity of commercial rape, acacia, and linden honeys. For uncertain commercial honey samples, genuine pure honeys constituted nearly 70%. We differentiate the adulteration of acacia and linden honeys with low-price rape honey. Our results reveal that 10% of commercial honeys were pure syrups. Overall, we seem to propose a novel and reliable solution to assess the authenticity of monofloral honey.

In this study the quality properties of Yemeni honeys were investigated. Two types of honey, monofloral (Sidr) and multi-flora honey originated from three different regions in Yemen (Hadramout, Dhamar and Amran governorates), were included in this study. Honey samples were collected and analyzed to determine their physicochemical properties such as (moisture content, total soluble solid (TSS), pH, free acidity, reducing sugars, sucrose, vitamin (C), electrical conductivity (EC), refractive index, water insoluble matter (WIM) and density) and to determine effect of geographical area and botanical source on the physicochemical properties of honey. The results showed that moisture content (18.63%±1.39), total soluble solid (TSS) content (79.58±1.42°Brix), pH (4.26±1.17), free acidity (17.16±5.56 meq/kg honey), reducing sugars (63.86%±3.50), sucrose content was (4.4%±1.12), total sugar (68.27%±3.55), vitamin C (0.65±0.226 mg/100g), the electrical conductivity (EC) (731.08±273.87μS/cm), refractive index (1.4958±0.0038), while water insoluble matter (WIM) was (0.092%±0.033) and the density was (1.3871±0.035 g/cm³). Results obtained from this study showed that honey samples coincide with those specified by Yemeni standard organization (YSMO) and Arabian Gulf standard organization (GSO). Botanical source affected on the pH, sucrose content and the electrical conductivity (EC) values of honey, which was higher in Sidr honey than multi floral honey samples. The geographical area caused a variation in the moisture, free acidity and vitamin C content of honey, while other physicochemical properties for honey had a negligible variation between honey from the different regions and botanical sources.

Research Concerning the Influence of the Use of Energo-protein Supplements-eco Certificate upon Physical-chemical Honey Indicators

Solid phase microextraction (SPME) followed by comprehensive two-dimensional gas chromatography coupled to a time-of-flight mass spectrometer (GC×GC-TOF-MS) was used to characterise volatile organic compounds in honeys of different botanical origins. Rape, sunflower, acacia, lime, raspberry, and phacelia honeys from Slovakia were studied in detail. Up to 900 compounds were detected at the given S/N ratio of 200. The poorest VOC profiles were found for acacia and rape honeys while lime honey showed the richest VOC composition. Approximately 100 compounds were present in all honeys studied, independently of their botanical origin. They belong to various chemical classes (hydrocarbons, alcohols, aldehydes and ketones, terpenes, benzene derivatives, and compounds containing heteroatoms). The compounds found in only one type of honey were also successfully identified.