单花种蜂蜜植物源黄酮标记物的研究进展

利用蜂蜜中特征成分来鉴别和标识不同种类单花种蜂蜜的植物源及其产地是当前蜂蜜研究的热点。文中介绍了黄酮化合物作为单花种蜂蜜植物源标记物的研究进展,旨在为我国单花种蜂蜜的溯源及其质量控制提供参考。     

Evaluation of pollen as a source of kaempferol in rosemary honey

The content of the flavonoid kaempferol in different experimental rosemary honey samples produced in Aragón (Spain) and in some commercial rosemary honey samples produced in different Spanish regions was evaluated by HPLC. The content ranged between 0·33 and 2·48 mg kg⁻¹ of honey. Nectar has been suggested recently as the origin of this flavonoid. Rosemary pollen contained kaempferol 3-diglucoside and 3-glucoside, and therefore could be an alternative source for the kaempferol found in rosemary honey. However, there was no correlation between the kaempferol present in honey and pollen content. This suggests that the contribution of pollen flavonoids to the pool of flavonoids found in honey is very small, and that the search for phenolic markers of the botanical origin of honey should be addressed to the identification of nectar flavonoids or other nectar constituents. © 1998 SCI.     

Characterisation of natural honey proteins: implications for the floral and geographical origin of honey

Characterisation of honey proteins has been considered advantageous for differentiating floral and geographical origin of honey. We analysed protein profiles of multi‐ and mono‐floral honey samples from different regions and harvest dates. The molecular masses of chromatographic peaks were in the range of 10–>200 kDa. Owing to comparable molecular masses, interesting correlation between profiles of honey proteins reported earlier and observed in this study could be established. Chromatograms of honey proteins revealed three novel peaks of molecular masses ～220, 129 and 26 kDa. Statistical analysis of peak areas showed that the 84‐kDa peak was different among all honey samples and the 220‐kDa peak was important for differentiation between multi‐ and mono‐floral honey samples. Chromatograms of several‐year‐old honey samples were different from fresh samples because of depletion of high molecular mass peaks that indicated in situ proteolysis. The results supported the notion of applying gel filtration as cost‐effective and robust technique for honey protein characterisation.     

Survey of 1,2-dicarbonyl compounds in commercial honey of different floral origin

In this study we conducted a survey of the concentrations of the major 1,2-dicarbonyl compounds in 40 commercial honey samples from 12 different floral origins. 3-Deoxyglucosone (3-DG), glyoxal (GO), and methylglyoxal (MGO) were measured, using their corresponding quinoxaline derivatives, by high-performance liquid chromatography (HPLC). The analytical performance of the HPLC method for the analysis of 1,2-dicarbonyl compounds was evaluated in terms of linearity, limits of detection (LODs), limits of quantification (LOQs), and precision. Linearity over 2 orders of magnitude, LODs (0.01-0.04 mg/kg), and LOQs (0.03-0.12 mg/kg) were calculated. Instrumental precision, as measured by the repeatability relative standard deviation% (RSDr%), was found to be between 0.22% and 0.55%. Furthermore, the concentrations of factors GO and MGO with respect to 3-DG were also calculated for rapid quantification in honey. In honey samples, the concentrations of 3-DG ranged from 75.9 to 808.6 mg/kg and were significantly higher (up to 100-fold) than those of 5-hydroxymethylfurfural (HMF). Values for GO and MGO were 0.1-10.9 and 0.2-2.9 mg/kg, respectively. The chemical characteristics that most influenced the levels of 1,2-dicarbonyl compounds in honey were found to be pH and total phenols. This was supported by multivariate analysis used to classify different honey types with respect to their chemical characteristics. In addition, both dicarbonyls and phenols are believed to contribute to the development of the final color of honey.     

Flavour compounds of Greek cotton honey

Finding marker compounds is a powerful tool in the determination of the botanical origin of honey. For this purpose the flavour fraction of Greek cotton honey was investigated. A striking characteristic of this type of honey is the presence of more than 35 phenolic compounds in the extract, accounting for almost 60% of the total amount of compounds positively identified by gas chromatography/mass spectrometry. In comparison with honeys of nine different origins, a total of 15 compounds could serve as potent markers for cotton honey, namely cinnamaldehyde (0.44%), cinnamyl alcohol (1.79%), cinnamic acid (1.13%), neryl and geranyl nitrile (0.16 and 0.41% respectively), benzenepropanol (0.5%), homovanillyl alcohol (0.6%), (E)‐ and (Z)‐p‐methoxy‐cinnamic acid (0.48 and 0.14% respectively), 2‐methyl‐p‐phthalaldehyde (0.22%), coniferaldehyde (0.47%), p‐coumaric acid (1.77%), ferulic acid (0.51%), scopoletin and scoparone (0.47%). Copyright © 2005 Society of Chemical Industry     

An HPLc technique for flavonoid analysis in honey

A new technique for the analysis of flavonoids in honey has been developed. This uses filtration of honey through Amberlite-XAD-2 and purification of the flavonoid fraction by Sephadex LH-20. The flavonoid fraction is then analysed by HPLC. This technique allowed the identification of 16 flavonoids in honey, namely quercetin, kaempferol, 8-methoxykaempferol, quercetin 3-methyl ether, isorhamnetin, kaempferol 3-methyl ether, quercetin 3,3-dimethyl ether, quercetin 3,7-dimethyl ether, galangin, luteolin, apigenin, genkwanin, chrysin, luteolin 7-methyl ether, pinocembrin and pinobanksin. The flavonoids present in ten samples of honey from La Alcarria have been HPLC analysed by this technique. The fact that the flavonoid patterns are very similar, suggests that samples from other areas should be examined in order to assess if this procedure could be useful as an adjunct in studies of the geographical origin of honey.     

Impedance spectroscopy for rapid determination of honey floral origin

In this work electrical impedance spectroscopy was applied as an alternative method for floral origin determination of unifloral honeys, which may supplement the labeling according to the European Legislation. Impedance measurements, in agreement with data from routine analyses, allowed to distinguish the unifloral honey samples and to acquire information on chemical and physical properties, such as conductivity, ash content and acidity. Equivalent electrical circuits have been extracted for each unifloral honey sample, which have been validated by means of electrical simulation, and every electrical component has been associated to a specific honey characteristic. It can be concluded that the method developed here permits rapid and easy determination of honey floral origin, no sample preparation procedure is required and it could be used in the official control laboratories.     

Application of a statistical approach to the classification of honey by geographic origin

Forty eight honeys from the La Rioja region of Spain were analysed to establish their quality. Fourteen legally required parameters of quality control were measured. Samples were obtained from two geographic areas of production: Valley and Sierra. These areas present different agroclimatic conditions and, thus, different flora. Classification of these honeys according to their geographic origin was achieved by applying multivariate statistical analysis to the chemical and physical data. Acidity (free acidity and pH), mineral content (electrical conductivity and ash) and factors related to degree of freshness (hydroxymethylfurfural and diastatic activity), were found to be the most important features for classification. Determination of the geographic origin of a La Rioja honey (Valley or Sierra) was possible with 83% accuracy using only these legally required quality control parameters; pollen studies were not necessary to achieve this objective.     

橙皮素对烟草青枯病的诱导抗性研究

为探究类黄酮诱导烟草抗青枯病的生理机制,从12种类黄酮化合物中筛选出对烟草青枯病防治效果最好的橙皮素,并对橙皮素处理后烟草叶片过氧化氢沉积、防御酶活性以及相关基因的表达量等进行了分析。结果表明,1mmol/L橙皮素对青枯菌无直接的抑菌作用,但对青枯病具有较明显的防控效果。橙皮素灌根处理诱发接种青枯菌烟草叶片过氧化氢的积累,显著提高叶片过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）的活性以及烟株次生代谢产物中酚类和类黄酮含量,上调表达Nt PR1a、Nt NPR1、Nt PAL抗性基因,从而提高烟株对青枯病的抗性。由此可知,橙皮素可作为诱抗剂有效防控青枯病的发生。     

HPLC flavonoid profiles as markers for the botanical origin of European unifloral honeys

The HPLC phenolic profiles of 52 selected unifloral honey samples produced in Europe were analysed to detect possible markers for the floral origin of the different honeys. Lime‐tree (five markers), chestnut (five markers), rapeseed (one marker), eucalyptus (six markers) and heather (three markers) honeys had specific markers with characteristic UV spectra. In addition, the flavanone hesperetin was confirmed as a marker for citrus honey, as well as kaempferol for rosemary honey and quercetin for sunflower honey. Abscisic acid, which had been reported to be a possible marker for heather honey, was also detected in rapeseed, lime‐tree and acacia honeys. Ellagic acid in heather honey and the hydroxycinnamates caffeic, p‐coumaric and ferulic acids in chestnut, sunflower, lavender and acacia honeys were also detected. The characteristic propolis‐derived flavonoids pinocembrin, pinobanksin and chrysin were present in most samples in variable amounts. © 2001 Society of Chemical Industry     

Determination of the botanical origin of honey by Fourier-transformed infrared spectroscopy: an approach for routine analysis

Fourier-transformed infrared spectroscopy has been established for analysing most of the physical–chemical parameters of honey. Additionally this technique can be used for determination of the botanical origin of a honey sample by comparison of the mid-infrared spectra. In this study calibrations for authentification of the main regional honey types should be developed to be able to measure simultaneously physical–chemical properties and the botanical origin at a minimum of time and at low costs. Honey samples from local beekeepers were collected and characterized by standard methods. The most common honey types were used for calibration. We recorded the mid infrared spectrum from each honey sample. Classification models were achieved by PCA-calibration and validated with samples from various botanical origins. Honey of Brassica spp., Robinia pseudoacacia, Calluna vulgaris, Trifolium spp., Tilia spp., Helianthus annuus, Centaurea cyanus and honeydew honey was used for calibration. Afterwards the calibration models were improved during routine analysis. Most of the honey samples from rape, false acacia, heather and honeydew can be classified correctly by the FTIR in consideration of the physical–chemical and sensorial properties.     

A comparative study on phenolic profile,vitamin C content and antioxidant activity of Italian honeys of different botanical origin

The aim of our study was to identify and quantify the phenolic acids, flavonoids and vitamin C and to evaluate the antioxidant activity in ninety Italian honeys of different botanical origins (chestnut, sulla, eucalyptus, citrus and multifloral). The results showed that total phenolic and flavonoid contents varied from 11.08 to 14.26 mg GAE per 100 g honey and from 5.82 to 12.52 mg QE per 100 g honey, respectively. HPLC–UV analysis showed a similar but quantitatively different phenolic profile of the studied honeys. Vitamin C is present in all samples. Multifloral honey showed the highest amount of the detected total phenolic compounds and the highest vitamin C content. The DPPH value varied from 55.06 to 75.37%. Among the unifloral honeys, chestnut honey presented the highest levels of phenolic acids, flavonoids and vitamin C, which are closely associated with its high antioxidant activity. The results show that honey contains high amount of biologically active compounds, which play an important role in defining the nutraceutical quality of the product, and that the distribution of these compounds is influenced by the botanical origin.     

Characterisation of Sierra Morena citrus blossom honey (Citrus sp)

The citrus blossom honey of Sierra Morena (a mountain chain located in the south of Spain) has been characterised by melissopalinological, physicochemical and sensorial analyses with the aim of establishing criteria for a future Protected Designation of Origin, which includes citrus blossom honey as one of the monofloral types produced in that region. Thus, a content in pollen of Citrus sp. ≥5%, Maurizio classes I and II was established, the accompanying pollen spectrum characteristic being that composed by the Myrtus, Echium, Lavandula, Reseda, Quercus, Olea, Crataegus and Cistus pollen types. The physicochemical parameters set were electrical conductivity ≤0.27 mS cm^?1; diastase activity≥ 6 diastase number; colour ≤20 mm Pfund and coordinate CIE‐Lab L = 89.72–95.18, a = ?1.28 to 1.05, b = 16.99–21.79, C = 17–21.82, H = 87.23°–92.01°; hydroximethylfurfural ≤10 mg kg^?1; free acidity ≤28 milliequivalents/litre and moisture ≤18.5%. From the sensorial study, the following profile, based on the evaluation of attributes on a five‐point scale, was obtained: colour white–pale yellow, fluidity (4.22), odour intensity (3.55), citrus blossom aroma/odour intensity (3.6/3.8), sweetness (3.14), acidity (2.36), freshness (61.5%) and persistence (2.9).     

Critical assessment of antioxidant‐related parameters of honey

In this study, several antioxidant‐related parameters were researched on 56 Spanish honeys, setting up and optimising some assays. Melissopalynology and colour (L*, a*, b*) were determined. Solid‐phase extraction (SPE) was used to obtain honeys’ phenolic extracts. Total phenolics, total flavonoids and trolox equivalent antioxidant capacity (TEAC) were determined in both honeys and extracts. It was verified that total flavonoids determination in neutral media must be carried out on extracts instead of on honeys, because of sugars’ interferences; likewise, extracts’ colours must be corrected in this assay. The endpoint for honeys’ trolox equivalent antioxidant capacity (TEAC) was researched. Significant linear relationships were found between TEAC values of honeys and honeys’ phenolic extracts, as well as between the results of TEAC measured at different times. Therefore, it would be possible to reliably calculate TEAC at 60 min (endpoint), measuring the absorbance at 6 min, thus saving analysis time and reducing costs.     

Authentication of honey sample via test sample and principal component analysis

The use of principal component analysis (PCA) of large data sets for the authentication of honey samples is illustrated. The procedure uses a predetermined training set of the most characteristic honeys selected by PCA from a large collection of various honeys. The PCA solution of the training set and sample in question, results in a plot indicating honey position and membership to rape, heather, or honeydew honey. The procedure is general and can be applied and extended for authentication of other foodstuffs.     

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.