Rape Honey Research Articles

Study on stable carbon isotope fractionation of rape honey from rape flowers (Brassica napus L.) to its unifloral ripe honey

A new idea and strategy for honey traceability and identification was provided by studying the carbon isotope fractionation of rape honey and its components in the different ripening process, as well as the fractionation from rape flowers, stamens, nectar to rape honey. The results showed the moisture content of rape honey continued to decrease, and the glucose and fructose content continued to increase during the ripening process. The δ13C of rape honey and its protein were less affected by honey ripeness, while the δ13C of sugars in rape honey were greatly affected by this. At the same time, the fractionation of carbon isotope from rape flowers to honey was significant. The δ13C of rape honey and its protein, disaccharide, fructose, and glucose had a strong correlation, and the δ13C of rape honey and its components were mainly related to rape flowers and its stamens.

WPŁYW CZASU PRZECHOWYWANIA NA WŁAŚCIWOŚCI ANTYOKSYDACYJNE I PROFIL POLIFENOLOWY MROŻONEGO I LIOFILIZOWANEGO CZERWIU TRUTOWEGO UTRWALONEGO W MIODZIE

Background. The purpose of the study was to evaluate the effect of drone brood fixation in rape honey and to analyze changes in its antioxidant activity during storage. The fixation was carried out for frozen and lyophilized drone brood, which were mixed with honey in various proportions (1, 2, and 4 % w/w). The antioxidant activity (DPPH and FRAP methods) and the total content of polyphenolic compounds (TPC) after 3, 6, and 9 months of storage were analyzed. After 9 months of storage, the polyphenolic profile (HPTLC method) and physicochemical parameters of samples were assessed. Results and conclusion. The addition of drone brood to honey increased the antioxidant activity of the final product considerably (by 33 to 110 %), while only slightly affected the physicochemical parameters (conductivity and a diastase number) compared to control honey. Moreover, honey with the addition of drone brood still continued to meet the requirements for honey standard. The polyphenol profile obtained by HPTLC method for honey with the addition of drone brood was enriched mainly with ellagic and ferulic acids compared to control honey. It was found that fixing the drone brood in honey allows to maintain its antioxidant properties for 6 months, whereas a significant decrease in reducing power (FRAP) and polyphenolic content (TPC) during prolonged storage were observed (from 8 to 26 % ). Due to the fact that lower losses were observed for the addition of frozen than for lyophilized drone brood after 9 months of storage, preserving the frozen brood in honey (up to 5 % w/w) can be recommended as an effective and inexpensive method available in apiary conditions.

Rape, sunflower and forest honeys for long-term environmental monitoring: Presence of indicator elements and non-photosynthetic carbon in old Hungarian samples

In this paper, we present the time-dependent elemental composition and AMS radiocarbon dating results of 36 rape, sunflower and forest honey samples, collected between 1985 and 2018 in geographically close locations. Based on the elemental information, we conclude that bee products regardless the type provide useful environmental information of the previous decades, such as the decreasing trend of airborne Pb emission can be traced. However, radiocarbon results agree less with the atmospheric bomb peak. Random offsets were observed in the specific radiocarbon activity of the honey samples indicating that rape, sunflower and forest honey samples are not as reliable materials for radiocarbon dating as acacia honeys. The radiocarbon results show that the rape, sunflower and forest honey samples can contain non-photosynthetic carbon, presumably derived from the soil. Thus, the complex application of honey samples for environmental reconstruction requires the species-separated investigation of bee products to reveal their adaptability for assessment approaches.

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.

Cover Image

The cover image is based on the Original Type Quality evaluation and geographical classification of immature rape and acacia honeys in China by Hong‐Yan Li et al., https://doi.org/10.1002/jsfa.11193.image

Comparison of Volatiles and Chemical Composition of Traditional and Non-Traditional Honey Available on the Polish Market

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).

Physicochemical parameters prediction and authentication of different monofloral honeys based on FTIR spectra

Samples of raspberry, mint, rape, sunflower, thyme, acacia and tilia honey were subjected to authentication using destructive (melissopalinological analysis and physicochemical parameters determination) and non-destructive (Fourier transform infrared spectroscopy – FTIR) methods. The melissopalinological analysis confirmed that all types of honey samples were authentic monofloral honey. To correlate the FTIR spectral information with the physicochemical parameters and therefore assess the usefulness of FTIR in the analysis of honey quality and authenticity, the spectral information was coupled with principal component analysis (PCA), linear discriminant analysis (LDA) and partial least square regression (PLS-R). PCA showed a clear separation can be observed for 5 groups of honey, namely: mint, rape, acacia, tilia and sunflower honeys, while thyme and raspberry honeys are mixing some samples. Moreover, the PLS-R model was found successful in predicting the physicochemical parameters of honey based on FTIR spectra. These results show that FTIR spectroscopy can be simultaneously used to confirm the authenticity of honey and also its quality and freshness.

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

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. 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. 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.

Molecular Mechanism of Mature Honey Formation by GC-MS- and LC-MS-Based Metabolomics.

Honey maturity is an important factor in evaluating the quality of honey; however, there are few studies on the molecular mechanism of the formation of mature honey (MH). In this study, the different metabolites of stomach honey (SH), immature honey (IMH), and MH samples during the same rapeseed flower season were analyzed by an UPLC-QTOF-MS-based metabolomics approach. MH was found to have a distinct metabolic profile to IMH, and a total of 9 different metabolites were obtained, 3 of which, including decenedioic acid, were accumulated in MH. Decenedioic acid as a bee-originated fatty acid (FA) was further verified in rape, acacia, and jujube honey by GC-MS, making it a potential marker to discriminate IMH and MH (P < 0.01). Besides, MH showed higher FAs concentrations; in particular, 3 FAs were significantly richer in MH than IMH (P < 0.05). This study reveals the molecular mechanism from IMH to MH from a FA perspective.

Characteristic Components and Authenticity Evaluation of Rape, Acacia, and Linden Honey.

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.

Melissopalynology, antioxidant activity and multielement analysis of two types of early spring honeys from Hungary

Two types of early spring Hungarian honeys, purchased as rape (Brassica napus L.) and ramson (Allium ursinum L.) honeys were identified and characterized. The 42 samples originated from various geographical locations, harvested in two different years. The unifloral origin of rape honeys was supported using melissopalynological analysis, while the samples marketed as ramson honeys were of multifloral origin with predominantly fruit tree or rape pollen grains. Color intensity and antioxidant capacities measured with 4 methods differed in uni- and multifloral honeys, but location and year of harvest had no influence within the honey types. Correlations were observed among antioxidant capacity values and color. The analysis of elements showed that essential elements were present in higher amounts in multifloral honeys, while in rape honeys the influence of geographical origin was observed. The concentrations of several toxic elements were below the detection limit (<0.1 mg kg−1) in the samples, indicating their good quality. Microscopical pollen analysis of honeys was used effectively to confirm their botanical origin, which was the most important factor to influence all of the measured parameters. Pollen spectrum, antioxidant potential and element content of honeys all served as useful indicators of their quality. Because of the large number of samples, this multi-level study provides reliable data about two types of early spring Hungarian honeys both for producers and consumers.

Fast Quantification of Honey Adulteration with Laser-Induced Breakdown Spectroscopy and Chemometric Methods

Honey adulteration is a major issue in food production, which may reduce the effective components in honey and have a detrimental effect on human health. Herein, laser-induced breakdown spectroscopy (LIBS) combined with chemometric methods was used to fast quantify the adulterant content. Two common types of adulteration, including mixing acacia honey with high fructose corn syrup (HFCS) and rape honey, were quantified with univariate analysis and partial least squares regression (PLSR). In addition, the variable importance was tested with univariable analysis and feature selection methods (genetic algorithm (GA), variable importance in projection (VIP), selectivity ratio (SR)). The results indicated that emissions from Mg II 279.58, 280.30 nm, Mg I 285.25 nm, Ca II 393.37, 396.89 nm, Ca I 422.70 nm, Na I 589.03, 589.64 nm, and K I 766.57, 769.97 nm had compact relationship with adulterant content. Best models for detecting the adulteration ratio of HFCS 55, HFCS 90, and rape honey were achieved by SR-PLSR, VIP-PLSR, and VIP-PLSR, with root-mean-square error (RMSE) of 8.9%, 8.2%, and 4.8%, respectively. This study provided a fast and simple approach for detecting honey adulteration.

Comparative study of labelled bee honey from Poland and the result of the melissopalynological analysis

The definition of a variety of natural bee honey is based on a melissopalynological analysis of the pollen grains that are the most prevalent and naming the variety of honey according to the botanical name of the plant. The purpose of this work was to compare the declarations of beekeepers regarding a variety of bee honey from Poland with the results of laboratory analysis. The study was conducted on 100 samples of bee honey. It was shown that 48% of the samples were incorrectly classified in the declared variety. Only heather honey samples showed 100% correct classification. In contrast, 7% of rape honey, 13% of buckwheat, 58% of multifloral, 68% of linden, 100% of dandelion and 100% of willow honey were wrongly named. The consumer, when looking for a specific variety of bee honey, expects health benefits, which is why individual parameters defining the quality of bee honeys, especially varieties, should be the subject of detailed and continuous monitoring.

The influence of temperature on the antioxidant potential in different types of honey*

Honey is the most popular bee product consumed by humans. It is known for its nutritional properties and health benefits, which include neuroprotective effects, the support of the circulatory system, and the beneficial influence it has on skin and respiratory system disorders. The aim of this study was to determine the influence of water temperature used for the preparation of honey solutions on their antioxidant potential. Material and methods. The study material included buckwheat honey, black locust honey, and rape honey. Honey solutions (1%) were prepared using distilled water with the temperatures: 25°C, 70°C, 80°C, and 90°C. The antioxidant activity of samples was measured with spectrophotometric method using synthetic radical DPPH. The antioxidant activity of honey was between 0.29 to 78.50% of DPPH inhibition, depending on the type of honey and the temperature of water used for the preparation of solutions. Buckwheat honey was characterised by the highest antioxidant potential. A significant, directly proportional correlation was observed between the antioxidant potential and the temperature of buckwheat and rape II honey solutions. In the case of buckwheat honey, rape honey I and black locust honey, the highest antioxidant potential was achieved in solutions prepared using distilled water at 90°C, whereas in the case of rape honey II, the highest values were observed at 80°C and 90°C. The lowest inhibition of the DPPH radical was observed in solutions at 70°C in all of the honey types. In the case of the studied honeys, it is even advisable to prepare water solutions at 80°C or 90°C in order to increase its antioxidant potential, e.g. by adding honey to tea or milk.

Metabolic profiling of organic acids in honey by stable isotope labeling assisted liquid chromatography-mass spectrometry

Organic acids in honey have great nutritive and medicinal value such as antimicrobial and antioxidant activities. In this study, profiling of organic acids in honey is carried out by sequential liquid-liquid extraction assisted isotope labeling-liquid chromatography-mass spectrometry. A total of 493 potential organic acids are detected in honey, and 165 of those are confirmed by comparing with authentic standards and interpretation of obtained MSn spectra. Findings from this study further expand our understanding about the number of organic acids in honey, increasing from 120 (previously reported) to 258. Moreover, we find that the composition of organic acids detected in rape, acacia and Chinese astragalus honey is quite similar; but their contents show certain variations. This study provides basic knowledge about the number and nature of organic acids in honey and could be stepping stone to explore the link between organic acids and nutritional and medicinal characteristics of honey.

Development of a real-time LAMP assay for monofloral honey authentication using rape honey

ABSTRACT 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 Effect of Adding the Leaves and Fruits of Morus alba to Rape Honey on Its Antioxidant Properties, Polyphenolic Profile, and Amylase Activity.

Two various species of mulberry (Morus sp.) were selected to enrich rape honey with dried leaves or lyophilized fruits (4% w/v). Finally, fruits and leaves of the ‘Ukraińska’ clone were introduced into the honey during creaming in concentrations from 1 to 4% w/v. The total phenolic content, antioxidant activity, anthocyanins content, and polyphenolic profile were tested in plant extracts and enriched honeys. Moreover, α-glucosidase, β-galactosidase, and diastase activities were investigated in honeys. For mulberry extracts, chlorogenic acid isomers and rutin were considered main antioxidant compounds. The antioxidant activity of honey enriched with mulberry leaves increased even more than 50 times, due to introducing numerous phenolic acids and flavonoid glycosides. A significant decrease in the diastase activity in honey depending on the content of added mulberry leaves (almost 50% decrease in the case of 4% addition) was found, suggesting the inhibitory effect of honey with mulberry leaves against carbohydrate hydrolyzing enzymes.

Detection of adulteration in Chinese monofloral honey using 1H nuclear magnetic resonance and chemometrics

Incidents of fraud are emerging on the domestic Chinese honey market, especially where lower value rape honey is mixed with high-value acacia honey. In this study, we use a combination of 1H NMR spectroscopy combined with chemometric techniques to detect and quantify adulteration of acacia honey with cheaper rape honey. The honey 1H NMR spectroscopy was split into three regions i.e. the aliphatic (0.00–3.00 ppm), carbohydrate (3.00–6.00 ppm) and aromatic (6.00–9.50 ppm) regions, to investigate which region provided the best qualitative and quantitative indicators in terms of rape honey adulteration in acacia honey. Results showed that the highest prediction accuracy for rape honey addition is 89.7 % using canonical discriminant analysis (CDA), determined from compounds located in 0.00–6.00 ppm spectral range. Orthogonal projection to latent structures discriminant analysis (OPLS-DA) was used to further discriminate samples of pure acacia honey adulterated with different amounts of rape honey. A partial least squares model (PLS) established a linear fit between the actual and predicted adulterant concentration with an R2 value up to 0.9996. When the content of rape honey added was less than 100 g/kg, the purity of acacia honey could still be estimated using 1H NMR spectroscopy and chemometric methods.

The influence of geographical origin on honey composition studied by Polish and Slovak honeys

Honey composition is mainly affected by botanical origin, however geographical factors as well as beekeeping practice and storage conditions can also influence its quality. The aim of the study was to determine the impact of geographical origin on physicochemical quality and biological activity of honey. For this reason Polish and Slovak varietal honeys, including per each country: 10 multifloral, 5 tilia, 5 rape, 5 acacia and 5 forest were compared according to their physicochemical parameters (free acidity, pH, electrical conductivity, moisture content, and colour intensity), sugar profile, diastase activity, as well as antioxidant activity (DPPH and FRAP tests, as well as photochemiluminescence method). Moreover, total phenolics compounds and flavonoids content were determined. The most significant differences (P &amp;lt; 0.05) between Polish and Slovak counterparts were found for tilia while the lowest for rape honeys. The impact of geographical origin on overall quality of honey was proved by PCA statistical tool.

Comparison of Physicochemical, Microbiological Properties and Bioactive Compounds Content of Grassland Honey and other Floral Origin Honeys.

The aim of this study was to compare the physicochemical, the microbiological, and the antioxidant characteristics of unifloral honey, polyfloral honey, honeydew, and hay meadows honey. Hay meadow is type of semi-natural grassland with a great floral diversity, an important resource for pollinators. Grasslands are the source of the spring nectar honey obtained in May and June. Water content, sugars (fructose, glucose, sucrose, trehalose, melezitose, maltose, erlose, turanose, and raffinose), electrical conductivity, phenolic content (gallic acid, protocatechuic acid, 4-hydrxybenzoic acid, vanilic acid, chlorogenic acid, caffeic acid, p-coumaric acid, rosmarinic acid, myricetin, quercitin, luteolin, kaempferol), color, viscosity, and microbiological characteristics were performed for all samples of honey. The total polyphenols content was significant for grassland honey (21.50 mg/100 g) and honeydew (30.49 mg/100 g) and less significant for acacia (0.08 mg/100 g) and rape honey (0.14 mg/100 g). All samples were microbiologically safe, and standard plate count (SPC) values were <10 cfu/g for all the samples, but the grassland honey had the highest microbiological quality: 33.3% of samples without microorganisms, 50.0% with the presence of yeast under limit, and 16.7% with yeast and mold under limit, a situation that does not meet other types of honey. The results of statistical analysis obtained with principal component analysis (PCA) showed a major difference between the grassland honey and the other types of honey.