Pyrrolizidine alkaloids in honey and bee pollen

A total of 3917 honey samples and 119 'bee pollen' samples (pollen collected by honeybees) were analysed for pyrrolizidine alkaloids (PAs). Some 0.05 M sulphuric acid was used for extraction followed by a clean-up step by means of solid-phase extraction. Separation and detection was achieved by target analysis using an LC-MS/MS system. PAs were found in 66% of the raw honeys (bulk honey not yet packaged in containers for sale in retail outlets) and in 94% of honeys available in supermarkets (retail honey). A total of 60% of the bee pollen samples were PA positive. The PA pattern was used to identify the potential origin of the PAs in honey, which was verified for the genus Echium by relative pollen analysis. The results give an estimate of the impact of PA-containing plants belonging to the genera Echium, Senecio and, to a certain extent, Eupatorium on PA levels in honey and can serve as a decision basis for beekeepers in order to find the most suitable location for the production of honey and bee pollen low in PAs.     

Pyrrolizidine alkaloids in floral honeys of tropical Ghana: a health risk assessment

ABSTRACT

There is a vast amount of information about the nutritional and medicinal properties of honey as a result of its numerous benefits. However, honeys have been found to be contaminated with hepatotoxic and carcinogenic pyrrolizidine alkaloids (PAs) on account of bees foraging on PA-containing plants. This study deals with the analysis of PAs in tropical honeys emanating from different agro-ecological zones of Ghana in order to assess its potential health risk. PAs of 48 honey samples were analysed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results show that a total of 85% of the honeys from various agro-ecological zones were PA positive including all honeys from supermarkets. The highest concentration of PAs was 2639 μg kg^?1, while the average PA concentration of the samples was 283 μg kg^?1. The study also found Chromolaena odorata pollens in majority of the honeys, thus indicating the plant as major source of PA contamination of honeys in the tropical regions.     

Pyrrolizidine alkaloids in honey: comparison of analytical methods

Pyrrolizidine alkaloids (PAs) are a structurally diverse group of toxicologically relevant secondary plant metabolites. Currently, two analytical methods are used to determine PA content in honey. To achieve reasonably high sensitivity and selectivity, mass spectrometry detection is demanded. One method is an HPLC-ESI-MS-MS approach, the other a sum parameter method utilising HRGC-EI-MS operated in the selected ion monitoring mode (SIM). To date, no fully validated or standardised method exists to measure the PA content in honey. To establish an LC-MS method, several hundred standard pollen analysis results of raw honey were analysed. Possible PA plants were identified and typical commercially available marker PA-N-oxides (PANOs). Three distinct honey sets were analysed with both methods. Set A consisted of pure Echium honey (61–80% Echium pollen). Echium is an attractive bee plant. It is quite common in all temperate zones worldwide and is one of the major reasons for PA contamination in honey. Although only echimidine/echimidine-N-oxide were available as reference for the LC-MS target approach, the results for both analytical techniques matched very well (n?=?8; PA content ranging from 311 to 520?µg?kg^?1). The second batch (B) consisted of a set of randomly picked raw honeys, mostly originating from Eupatorium spp. (0–15%), another common PA plant, usually characterised by the occurrence of lycopsamine-type PA. Again, the results showed good consistency in terms of PA-positive samples and quantification results (n?=?8; ranging from 0 to 625?µg?kg^?1 retronecine equivalents). The last set (C) was obtained by consciously placing beehives in areas with a high abundance of Jacobaea vulgaris (ragwort) from the Veluwe region (the Netherlands). J. vulgaris increasingly invades countrysides in Central Europe, especially areas with reduced farming or sites with natural restorations. Honey from two seasons (2007 and 2008) was sampled. While only trace amounts of ragwort pollen were detected (0–6.3%), in some cases extremely high PA values were detected (n?=?31; ranging from 0 to 13019?µg?kg^?1, average?=?1261 or 76?µg?kg^?1 for GC-MS and LC-MS, respectively). Here the results showed significantly different quantification results. The GC-MS sum parameter showed in average higher values (on average differing by a factor 17). The main reason for the discrepancy is most likely the incomplete coverage of the J. vulgaris PA pattern. Major J. vulgaris PAs like jacobine-type PAs or erucifoline/acetylerucifoline were not available as reference compounds for the LC-MS target approach. Based on the direct comparison, both methods are considered from various perspectives and the respective individual strengths and weaknesses for each method are presented in detail.     

Pyrrolizidine alkaloids in honey: comparison of analytical methods

Pyrrolizidine alkaloids (PAs) are a structurally diverse group of toxicologically relevant secondary plant metabolites. Currently, two analytical methods are used to determine PA content in honey. To achieve reasonably high sensitivity and selectivity, mass spectrometry detection is demanded. One method is an HPLC-ESI-MS-MS approach, the other a sum parameter method utilising HRGC-EI-MS operated in the selected ion monitoring mode (SIM). To date, no fully validated or standardised method exists to measure the PA content in honey. To establish an LC-MS method, several hundred standard pollen analysis results of raw honey were analysed. Possible PA plants were identified and typical commercially available marker PA-N-oxides (PANOs). Three distinct honey sets were analysed with both methods. Set A consisted of pure Echium honey (61-80% Echium pollen). Echium is an attractive bee plant. It is quite common in all temperate zones worldwide and is one of the major reasons for PA contamination in honey. Although only echimidine/echimidine-N-oxide were available as reference for the LC-MS target approach, the results for both analytical techniques matched very well (n = 8; PA content ranging from 311 to 520 μg kg(-1)). The second batch (B) consisted of a set of randomly picked raw honeys, mostly originating from Eupatorium spp. (0-15%), another common PA plant, usually characterised by the occurrence of lycopsamine-type PA. Again, the results showed good consistency in terms of PA-positive samples and quantification results (n = 8; ranging from 0 to 625 μg kg(-1) retronecine equivalents). The last set (C) was obtained by consciously placing beehives in areas with a high abundance of Jacobaea vulgaris (ragwort) from the Veluwe region (the Netherlands). J. vulgaris increasingly invades countrysides in Central Europe, especially areas with reduced farming or sites with natural restorations. Honey from two seasons (2007 and 2008) was sampled. While only trace amounts of ragwort pollen were detected (0-6.3%), in some cases extremely high PA values were detected (n = 31; ranging from 0 to 13019 μg kg(-1), average = 1261 or 76 μg kg(-1) for GC-MS and LC-MS, respectively). Here the results showed significantly different quantification results. The GC-MS sum parameter showed in average higher values (on average differing by a factor 17). The main reason for the discrepancy is most likely the incomplete coverage of the J. vulgaris PA pattern. Major J. vulgaris PAs like jacobine-type PAs or erucifoline/acetylerucifoline were not available as reference compounds for the LC-MS target approach. Based on the direct comparison, both methods are considered from various perspectives and the respective individual strengths and weaknesses for each method are presented in detail.     

Pyrrolizidine alkaloids in food: downstream contamination in the food chain caused by honey and pollen

In recent years, there has been a steadily growing number of published data on pyrrolizidine alkaloids (PAs) in honey and pollen. This raises the question whether honey and/or pollen used as ingredients in food processing might provoke a downstream contamination in the food chain. Here we addressed two different facets in connection with PAs in honey and pollen. First, we analysed the PA content of several food types such as mead (n?=?19), candy (n?=?10), fennel honey (n?=?9), soft drinks (n?=?5), power bars and cereals (n?=?7), jelly babies (n?=?3), baby food (n?=?3), supplements (n?=?3) and fruit sauce (n?=?1) that contained honey as an ingredient in the range of 5% to approximately 37%. Eight out of 60 retail samples were tested as being PA-positive, corresponding to 13%. Positive samples were found in mead, candy and fennel honey, and the average PA content was calculated to be 0.10?µg?g^–1 retronecine equivalents (ranging from 0.010 to 0.484?µg?g^–1). Furthermore, we investigated the question whether and how PAs from PA pollen are transferred from pollen into honey. We conducted model experiments with floral pollen of Senecio vernalis and PA free honey and tested the influence of the quantity of PA pollen, contact time and a simulated honey filtration on the final PA content of honey. It could clearly be demonstrated that the PA content of honey was directly proportional to the amount of PA pollen in honey and that the transfer of PAs from pollen to honey was a rather quick process. Consequently, PA pollen represents a major source for the observed PA content in honey. On the other hand, a good portion remains in the pollen. This fraction is not detected by the common analytical methods, but will be ingested, and it represents an unknown amount of ‘hidden’ PAs. In addition, the results showed that a technically and legally possible honey filtration (including the removal of all pollen) would not be an option to reduce the PA level of the final product significantly.     

Jakobs-Kreuzkraut (<Emphasis Type="Italic">Senecio jacobaea</Emphasis>): eine Ursache für Pyrrolizidin-Alkaloide im Sommerhonig?

Pyrrolizidine alkaloids (PAs) are secondary plant compounds, which may be carried into honey by honey bees (Apis mellifera) and thus enter the human food chain. Depending on the quantity consumed, PAs are considered harmful to human health. At present, however, there is no statutory limit for PAs in foodstuffs. Because of several hints that larger occurrences of PA-containing tansy ragwort (Senecio jacobaea) may be responsible for PAs in summer honeys, honey samples from regions with and without tansy ragwort from all across Schleswig-Holstein were tested for their PA content (28 individual PAs) by LC-MS/MS analysis in 2014. By including honey samples from surroundings of flower plots established on arable land, it was tested if the carry-over of PAs into honey can be reduced by “distraction feed”. Samples from regions with tansy ragwort showed significantly higher PA contents than those from regions without tansy ragwort. Flower plots had no significant influence on the PA content. PAs were detected in 53.5 % of the 86 honey samples investigated. The mean PA value of PA-positive honeys was much higher than the median value since the sample comprised only few high and many low values. 28.6 % of the detected PAs were not from Senecio species, but from the Borage family (Boraginaceae) or Hemp Agrimony (Eupatorium cannabinum). In 2.3–15.1 % of the samples the limit value recommended by the BfR (Analytik und Toxizität von Pyrrolizidinalkaloiden sowie eine Einschätzung des gesundheitlichen Risikos durch deren Vorkommen in Honig. Stellungnahme Nr. 038/2011 des BfR vom 11. August 2011, ergänzt am 21. Januar 2013. Bundesinstitut für Risikobewertung [Hrsg.], Berlin: 37 S, 2013a) for different eating habits was exceeded. Because of the potential risk to human health, beekeepers and users of land with larger occurrences of tansy ragwort should take joint measures to keep the PA load in summer honeys as low as possible.     

Pyrrolizidine alkaloids: their occurrence in Spanish honey collected from purple viper’s bugloss (Echium spp.)

The incidence and concentration of pyrrolizidine alkaloids (PAs) from Echium spp. plant have been defined in 103 Spanish honey samples. Each sample was examined to determine total pollen content, the percentage of Echium spp. pollen, and simultaneous measurements of PAs and their N-oxides concentrations by the HPLC-ESI/MS method to identify the potential origin of PAs in honey. PAs were found in 94.2% of the raw honey samples analysed, in the range of 1–237 µg kg^?1 (average concentration = 48 µg kg^?1). The PA pattern was clearly dominated by echimidine, lycopsamine and their N-oxides, representing the 97.8% of total ∑PAs, and only echimidine and echimidine-N-oxide surpassed the 87% of total ∑PA content. Others PAs, seneciphylline and heliotrine-N-oxide, appear to be reported in a lower incidence and concentration (average of 3 and 1 µg kg^?1, respectively). The Pearson Chi-squared test (p ≤ 0.01) confirms the non-correspondence between pollen plants and PA content. This study was also realised to generate a dataset in order to evaluate the potential risk of Spanish honeys containing PA plants belonging to the genera Echium.     

Influence of grass pellet production on pyrrolizidine alkaloids occurring in Senecio aquaticus-infested grassland

1,2-Dehydro-pyrrolizidine alkaloids (PA) and their N-oxides (PANO) exhibit acute and chronic toxic effects on the liver and other organs and therefore are a hazard for animal and human health. In certain regions of Germany, an increasing spread of Senecio spp. (ragwort) on grassland and farmland areas has been observed during the last years leading to a PA/PANO-contamination of feed and food of animal and plant origin.

This project was carried out to elucidate whether the process of grass pellet production applying hot air drying influences the content of PA and PANO. Samples of hay (n = 22) and grass pellets (n = 28) originated from naturally infested grassland (around 10% and 30% dominance of Senecio aquaticus) and from a trial plot with around 50% dominance. Grass pellets were prepared from grass originating from exactly the same plots as the hay samples. The samples were analysed by liquid chromatography-tandem mass spectrometry for PA/PANO typically produced by this weed.

The results of the study revealed that PA/PANO levels (predominantly sum of senecionine, seneciphylline, erucifoline and their N-oxides) in hay ranged between 2.1 and 12.6 mg kg^?1 dry matter in samples with 10% and 30% dominance of S. aquaticus, respectively. Samples from the trial plot (50% dominance) had levels of up to 52.9 mg kg^?1. Notably, the hot air drying process during the production of grass pellets did not lead to a reduction of PA/PANO levels. Instead, the levels in grass pellets with 10% and 30% S. aquaticus ranged from 3.1 to 55.1 mg kg^?1. Grass pellets from the trial plot contained up to 96.8 mg kg^?1. In conclusion, hot air drying and grass pellet production did not affect PA/PANO contents in plant material and therefore, heat-dried products cannot be regarded as safe in view of the toxic potential of 1,2-dehydro-pyrrolizidine alkaloids.     

Pyrrolizidine alkaloids in food: downstream contamination in the food chain caused by honey and pollen

In recent years, there has been a steadily growing number of published data on pyrrolizidine alkaloids (PAs) in honey and pollen. This raises the question whether honey and/or pollen used as ingredients in food processing might provoke a downstream contamination in the food chain. Here we addressed two different facets in connection with PAs in honey and pollen. First, we analysed the PA content of several food types such as mead (n = 19), candy (n = 10), fennel honey (n = 9), soft drinks (n = 5), power bars and cereals (n = 7), jelly babies (n = 3), baby food (n = 3), supplements (n = 3) and fruit sauce (n = 1) that contained honey as an ingredient in the range of 5% to approximately 37%. Eight out of 60 retail samples were tested as being PA-positive, corresponding to 13%. Positive samples were found in mead, candy and fennel honey, and the average PA content was calculated to be 0.10 μg g(-1) retronecine equivalents (ranging from 0.010 to 0.484 μg g(-1)). Furthermore, we investigated the question whether and how PAs from PA pollen are transferred from pollen into honey. We conducted model experiments with floral pollen of Senecio vernalis and PA free honey and tested the influence of the quantity of PA pollen, contact time and a simulated honey filtration on the final PA content of honey. It could clearly be demonstrated that the PA content of honey was directly proportional to the amount of PA pollen in honey and that the transfer of PAs from pollen to honey was a rather quick process. Consequently, PA pollen represents a major source for the observed PA content in honey. On the other hand, a good portion remains in the pollen. This fraction is not detected by the common analytical methods, but will be ingested, and it represents an unknown amount of 'hidden' PAs. In addition, the results showed that a technically and legally possible honey filtration (including the removal of all pollen) would not be an option to reduce the PA level of the final product significantly.     

Effect of Adulteration versus Storage on Volatiles in Unifloral Honeys from Different Floral Sources and Locations

High fructose corn syrup (HFCS) was added at 5% to 40% to Indiana wildflower honey and added at 40% to Ohio and Indiana honeys from blueberry, star thistle, clover and wildflower, and an unknown source to simulate honey adulteration. Unadulterated honeys were also stored at 37 ºC from 1 to 6 mo. The volatile composition was measured by Selected Ion Flow Tube Mass Spectrometry (SIFT‐MS). Most volatiles decreased in concentration with both increasing HFCS and storage time. Furfural significantly increased in concentration in all adulterated honeys and 1,3‐butanediol, acetonitrile, and heptane in some adulterated honeys. During storage, the volatiles that increased were maltol, furfural, 5‐methylfurfural, and 5‐hydroxymethyl furfural in all honeys and also acetic acid and 1‐octen‐3‐ol levels in some honeys. Soft independent modeling by class analogy (SIMCA) was used to differentiate the volatile profiles of adulterated honeys from fresh and stored honeys. The volatile profiles of honeys in accelerated storage for up to 4 mo and the honeys adulterated with 40% HFCS were significantly different. Acetic acid had the most discriminating power in Ohio star thistle and blueberry honeys and unknown honey while furfural had the greatest discriminating power in Indiana blueberry, star thistle, and clover honeys. Adulteration and storage of honey both reduced the volatile levels, but since they changed the volatile composition of the fresh honey differently, SIMCA was able to differentiate adulteration from storage. Practical Application: Analysis of adulterated and stored honeys determined that both decrease volatile levels, and no clear indicator volatiles were found. However, SIMCA can be used to distinguish the volatile profiles of fresh or stored honeys, from adulterated honeys.     

Detection of pyrrolizidine alkaloids in commercial honey using liquid chromatography–ion trap mass spectrometry

Pyrrolizidine alkaloids (PAs) are known secondary plant metabolites which can cause hepatotoxicity in both humans and livestock. PAs can be consumed through the use of plants for food, medicinal purposes and as contaminants of agricultural crops and food. PA contaminated grain has posed the largest health risk, although any PA contamination in our food chain should be recognised as a potential health threat. For this purpose, retail honeys were tested by LC–MS/MS. The method allows for specific identification of toxic retronecine and otonecine-type PAs by comparison to reference compounds via a spectral library. In total, 50 honey samples were matched to the reference spectra within a set of tolerance parameters. Accurate data analysis and quick detection of positive samples was possible. Positive samples contained an average PA concentration of 1260 μg kg^?1 of honey. Good linear calibrations were obtained (R² > 0.991). LOD and LOQ ranged from 0.0134 to 0.0305 and 0.0446 to 0.1018 μg mL^?1, respectively.     

Pyrrolizidine alkaloids (PAs) in honey and pollen‐legal regulation of PA levels in food and animal feed required

Pyrrolizidine alkaloids (PAs) are secondary plant constituents that comprise about 400 different structures and occur in two major forms, a tertiary form and the corresponding N‐oxide. PAs containing a 1,2‐double bond are pre‐toxins and metabolically activated by the action of hepatic P‐450 enzymes to toxic pyrroles. Besides the acute toxic effects, the genotoxic and tumorigenicity potential of PAs was demonstrated in some eukaryotic model systems. Recently, the potential PA contamination of food and feeding stuff attracted recurrent great deals of attention. Humans are exposed to these toxins by consumption of herbal medicine, herbal teas, dietary supplements or food containing PA plant material. In numerous studies the potential threat to human health by PAs is stated. In pharmaceuticals, the use of these plants is regulated. Considering the PA concentrations observed especially in authentic honey from PA producing plants and pollen products, the results provoke an international regulation of PAs in food.     

Quantification of pyrrolizidine alkaloids in North American plants and honey by LC-MS: single laboratory validation

Pyrrolizidine alkaloids (PAs) are a class of naturally occurring compounds produced by many flowering plants around the World. Their presence as contaminants in food systems has become a significant concern in recent years. For example, PAs are often found as contaminants in honey through pollen transfer. A validated method was developed for the quantification of four pyrrolizidine alkaloids and one pyrrolizidine alkaloid N-oxide in plants and honey grown and produced in British Columbia. The method was optimised for extraction efficiency from the plant materials and then subjected to a single-laboratory validation to assess repeatability, accuracy, selectivity, LOD, LOQ and method linearity. The PA content in plants ranged from1.0 to 307.8 µg/g with repeatability precision between 3.8 and 20.8% RSD. HorRat values were within acceptable limits and ranged from 0.62 to 1.63 for plant material and 0.56–1.82 for honey samples. Method accuracy was determined through spike studies with recoveries ranging from 84.6 to 108.2% from the raw material negative control and from 82.1–106.0 % for the pyrrolizidine alkaloids in corn syrup. Based on the findings in this single-laboratory validation, this method is suitable for the quantitation of lycopsamine, senecionine, senecionine N-oxide, heliosupine and echimidine in common comfrey (Symphytum officinale), tansy ragwort (Senecio jacobaea), blueweed (Echium vulgare) and hound’s tongue (Cynoglossum officinale) and for PA quantitation in honey and found that PA contaminants were present at low levels in BC honey.     

Determination of physicochemical properties of multifloral honeys stored in different containers

In comparison with the initial values, acidity and 5‐(hydroxy‐methyl)‐2‐furaldehyde (HMF) values of all honey samples increased during storage. The total phenol contents of honey were decreased from 286.2 to 108.6 mg GAE/kg during 9 months of storage in white colored container. In addition, total phenol contents of honey sample stored in tin container ranged from 294.7 to 258.6 mg GAE/kg (p < .05). While radical scavenging activity values of honey samples stored in amber colored container during storage are measured as 78.6 g/L, IC₅₀, 77.9 g/L, IC50, and 76.1 g/L, IC₅₀, these activity values were determined as 84.9 g/L, IC₅₀, 80.7 g/L, IC_50, and 75.2 g/L, IC₅₀ in tin container (p < .05), respectively. While acidity values of honey samples stored in white bottle range from 23.6 (3th month) to 25.7% (9th month), it varied from 20.6 (3th month) to 21.6% (9th month) in honey sample stored in amber colored container during storage.

Practical applications

Different honeys are produced in different parts of Turkey. The known honeys are pine, citrus, and chestnut honey. Various flower honeys are produced in these and other regions. HMF formation is considered as a bed result of storage and heating.     

Investigation of pyrrolizidine alkaloids including their respective N-oxides in selected food products available in Hong Kong by liquid chromatography electrospray ionisation mass spectrometry

ABSTRACT

This study determined the levels of pyrrolizidine alkaloids (PAs), including their respective N-oxides, in foodstuffs available in Hong Kong by liquid chromatography-electrospray ionisation tandem mass spectrometry. A total of 234 samples (48 food items) were collected randomly from a local market and analysed. About 50% of samples were found to contain detectable amount of PAs. Amongst the 48 food items, PAs were not detected in 11 food items, including barley flour, beef, cattle liver, pork, pig liver, chicken meat, chicken liver, milk, non-fermented tea, Melissa tea and linden tea. For those found to contain detectable PAs, the summed PA content ranged up to 11,000 µg kg^?1. The highest sum of PA content among the 37 food items calculated with lower bound was cumin seed, then followed by oregano, tarragon and herbs de Provence with ranges of 2.5–11,000, 1.5–5100, 8.0–3300 and 18–1300 µg kg^?1 respectively. Among the samples, the highest sum of PA content was detected in a cumin seed sample (11,000 µg kg^?1), followed by an oregano (5100 µg kg^?1), a tarragon (3300 µg kg^?1) and a herbs de Provence (1300 µg kg^?1). In general, the results of this study agreed well with other published results in peer-reviewed journals, except that the total PAs in honey and specific tea infusion in this study were comparatively lower.     

Degradation of 5‐Hydroxymethylfurfural in Honey

ABSTRACT: 5‐Hydroxymethylfurfural (HMF) is the most important intermediate product of the acid‐catalyzed dehydration reaction of hexoses and/or Maillard reaction; furthermore, it is the most used index to evaluate thermal damages or ageing in food products. Usually its degradation reactions, being very slow, are neglected. This study reports the findings concerning the degradation kinetics of HMF, in honeys of different floral origin at a temperature between 25 and 50 °C. The results highlighted higher degradation rates (k_{HMFdegradation}) compared to the corresponding formation rates (k_HMFformation) in chestnut and citrus samples. Similar k‐values were found in multifloral honey. Moreover, the reaction of HMF degradation was characterized by lower activation energy (E_a) values compared to E_a formation values. The final concentration of HMF in honey, during storage at room temperature, should be ascribed to high sugar concentration. The fluctuation of HMF in honeys could depend on the equilibrium between the accumulation and the degradation processes. This can affect the validity of HMF as storage index in some honeys, above all during the analysis of those honeys whose legislation is too restrictive (citrus) or in chestnut honey analysis where it does not accumulate.     

Analysis of minority honey components: Possible use for the evaluation of honey quality

The minerals (Al, B, Ca, Cu, Mg, Mn, Ni, Zn) of 24 authentic Czech nectar and honeydew honey samples (2003 and 2004 harvests) were determined, to find the relationship between their content and the origin or type of honey. The concentrations of analytes in the digests, obtained via optimised dry decomposition of honey samples, were measured by flame atomic absorption spectrometry (F-AAS), as well as optical emission spectrometry with inductively coupled plasma (ICP-OES). With regard to its speed of analysis and cost, ICP-OES was the more favourable method. By combining the analytical data and electrolytic conductivities of samples, the honey samples could be divided into two groups – honeydew honeys and nectar honeys. Like Slovak and Polish honeys, samples of Czech honeys had higher nickel levels than honeys originating from other parts of the world.     

Application of Selected Ion Flow Tube Mass Spectrometry Coupled with Chemometrics to Study the Effect of Location and Botanical Origin on Volatile Profile of Unifloral American Honeys

Abstract: Ten Ohio and Indiana honey samples from star thistle (Centaurea Americana), blueberry (Vaccinium spp.), clover (Trifolium spp.), cranberry (Vaccinium spp.), wildflower, and an unknown source were collected. The headspace of these honeys was analyzed by selected ion flow tube mass spectrometry and soft independent modeling of class analogy (SIMCA). SIMCA was utilized to statistically differentiate between honeys based on their composition. Ohio honeys from star thistle, blueberry, and clover were similar to each other in volatile composition, while Ohio wildflower honey was different. Indiana honeys from star thistle, blueberry, and wildflower were different from each other in volatile composition, while clover and cranberry honeys were similar. Honeys from Ohio and Indiana with the same floral origins were different in volatile composition. Furfural, 1‐octen‐3‐ol, butanoic, and pentanoic acids were the volatiles with the highest discriminating power between types of floral honey. Methanol and ethanol followed by acetic acid were at the highest levels in most honeys, though furfural was at the highest concentration in Indiana blueberry honey, while 1‐octen‐3‐ol was at the highest concentration in Indiana wildflower honey. The highest concentration of volatile compounds was in Indiana wildflower honey followed by Ohio wildflower honey, while the lowest concentration of volatile compounds was observed in Ohio clover honey followed by Indiana clover honey. Practical Application: Using chemometrics, concentrations of volatile compounds in different honeys can be used to determine the influence of botanical and geographical origins on aroma, which is important for the quality of honey. Characterization of volatile compounds can also be a useful tool for assessing honey quality.     

Characterization of monofloral honeys with multivariate analysis of their chemical profile and antioxidant activity

Abstract: Various bioactive chemical constituents were quantified for 21 honey samples obtained at Rio de Janeiro and Minas Gerais, Brazil. To evaluate their antioxidant activity, 3 different methods were used: the ferric reducing antioxidant power, the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activity, and the 2,2′‐azinobis (3‐ethylbenzothiazolin)‐6‐sulfonate (ABTS) assays. Correlations between the parameters were statistically significant (?0.6684 ≤ r ≤?0.8410, P < 0.05). Principal component analysis showed that honey samples from the same floral origins had more similar profiles, which made it possible to group the eucalyptus, morrão de candeia, and cambara honey samples in 3 distinct areas, while cluster analysis could separate the artificial honey from the floral honeys. Practical Application: This research might aid in the discrimination of honey floral origin, by using simple analytical methods in association with multivariate analysis, which could also show a great difference among floral honeys and artificial honey, indicating a possible way to help with the identification of artificial honeys.     

Changes in the volatile fractions and sensory properties of heather honey during storage under different temperatures

A comparative study of the temperature effect on the physicochemical parameters, volatile composition and sensory quality of heather honey stored during 1 year was performed. The temperatures evaluated were refrigerated (10 °C), room (20 °C) and high temperatures (40 °C). The cooling storage of heather honey presented advantages such as the retention of compounds like lilac aldehyde and lower looses of terpene derivatives, β-damascenone, benzaldehyde and phenylacetaldehyde, compared with other storage temperatures. Heather honey stored under room temperature showed significant increases in levels of 2-furanmethanol, furaneol, 2-methyl furancarboxylate, maltol and 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP). These compounds, whose concentrations were extremely high in honeys submitted at 40 °C, are suggested as useful indices of unsuitable storage temperature. Moreover, the occurrence of methyl cyclotene and ethyl cyclotene are proposed as new markers indicatives of over-heating treatment of honey. Sensory analysis showed that off-flavours such as medicine and toasted, detected in honeys submitted at 40 °C, began to be perceived in the samples stored at room temperature, while heather honeys refrigerated (10 °C) kept the organoleptic profile and quality similar to fresh heather honey.