Physicochemical properties of some honeys produced from different plants in Morocco

Abstract Seventy-three Moroccan honey samples were collected between 2005 and 2008. In this study, water content, pH, acidity (free, lactone and total acidity), electrical conductivity (EC), colour, diastase, hydroxymethylfurfural (HMF) and sugar content were all determined in different types of bee honey which include multifloral, honeydew and nine types of unifloral honeys ( Euphorbia resinifera , Euphorbia echinus , Citrus , eucalyptus, carob, thyme, lavender, Ziziphus and rosemary). The moisture shows values of 14.3% and 20.2%, pH between 3.52 and 5.13, the total acidity ranges between 11.94 and 58.03 meq kg −1 , hydroxymethylfurfural (HMF) content shows values between 0.09 and 53.38 mg kg −1 ; diastase values were between 4.3° and 24.6° Gothe; electrical conductivity between 119.9 and 1741 μs cm −1 and fructose, glucose and sucrose values range between 35.07–46.26%, 23.7–39.3% and 0.42–2.98%. A statistical analysis was carried out to classify 10 types of honeys, and identified the most significant parameters, using analysis of variance, principal component analysis (PCA) and stepwise discriminant analysis (SDA). PCA showed that the cumulative variance was 74.97% and about 88.9% of samples was correctly classified. The principal aim of this study was to contribute more to the knowledge of the Moroccan honeys by means of the analysis of chemical composition and of physical parameters. Seventy-three Moroccan unifloral, multifloral and honeydew honey samples, including types that have never been studied before, produced in different regions in Morocco ( Table 1 , Table 2 ), were analysed to define its main features. As a consequence, we present data on water content, electrical conductivity, pH, free acidity, lactone acidity, total acidity, diastase, 5-(hydroxymethyl)-2-furaldehyde (HMF) amounts, fructose, glucose and sucrose

Evaluation of authenticity and botanic origin of buckwheat honeys on the basis of their physiochemical, phenolic and volatile composition data

Honey is a remarkably complex natural liquid produced by bees from plants nectars, plant secretions and excretions of plant sucking insect. Its composition depend strongly on the plant species, although external factors also play a role, such as seasonal, environmental factors and processing conditions. Honey consists of a supersaturated solution of sugars, of which the main contributors are fructose (38%) and glucose (31%). A wide range of minor constituents is also present in honey, many of which, including phenolic compounds, are known to have antioxidant proprieties. The presence of this substances highlight the role of honey as a nutritional source of natural antioxidants with a wide range of biological effects, such as anti-bacterial, anti-inflammatory, anti-thrombotic, but also anticancer and anticarcinogenic proprieties. Buckwheat honey is a dark honey produced by bees that collect pollen and nectar from the little pink flowers of the buckwheat plant (Fagopyrum esculentum M\uf6ench, Polygonaceae), popularly recognized as an excellent honey source and a selective antioxidant and hypolipidaemic nutrient food. In literature have been reported the high antioxidant proprieties of the buckwheat honey, as well as its antibacterial activity. Considering the several health benefits of this honey, the principal aim of this work was the characterization of some buckwheat honeys. Ten buckwheat honey samples, from different collection place, were characterized on the basis of their pollen, physicochemical, phenolic and volatile composition data. Electrical conductivity, optical rotation, pH and sugar composition were the physicochemical parameters with higher discrimination, showing the presence of three blended honeys. Honey volatiles, analysed by solid phase microextraction (SPME) and gas chromatography mass-spectrometry (GC/MS), revealed more than 100 volatile compounds, most of them present in all honey samples even though with quantitative variation. Besides many furfural derivates, 3-methylbutanoc acid was the main volatile compound found in most of the samples. The presence of 2- and 3-methylbutanal, pheynalcetaldehyde, among with 3- methylbutanoic acid confirmed the typical buckwheat aroma of some studied samples and corroborated physiochemical data. HPLC-MS phenolic profile did not show significant differences cross the honeys and p-coumaric and p-hydroxybenzoic acid were found to be the most abundant compounds in all buckwheat honeys. While melissopalynological analysis remains nowadays as the only technique which allows a direct botanical source characterization, physicochemical parameters afford quantitative results, allowing an approximate estimation of the kind of honey and the possible presence of honey blends. Also volatile and phenolic compounds function as important role in honey characterization and improves our knowledge about honey as a source of antioxidants

Electronic nose and neural network use for the classification of honey

Seventy samples of honey of different geographical and botanical origin were analysed with an electronic nose. The instrument, equipped with 10 Metal Oxide Semiconductor Field Effect Transistors (MOSFET) and 12 Metal Oxide Semiconductor (MOS) sensors, was used to generate a pattern of the volatile compounds present in the honey samples. The sensor responses were evaluated by Principal Component Analysis (PCA) and Artificial Neural Network (ANN). Good results were obtained in the classification of honey samples by using a neural network model based on a multilayer perceptron that learned using a backpropagation algorithm. The methodology is simple, rapid and results suggest that the electronic nose could be a useful tool for the characterisation and control of honey

Buckwheat honeys: Screening of composition and properties

The quality of 10 buckwheat honeys, collected from Italian and est European beekeepers declaring to produce monofloral honey, were evaluated by means of their pollen, physicochemical, phenolic and volatile composition data. The results of the traditional analyses and in particular electrical conductivity, optical rotation, pH and sugar composition revealed some poorly pure samples that could not fit in the buckwheat tipology. Honey volatiles, analysed by solid phase microextraction (SPME) and gas chromatography\u2013 mass-spectrometry (GC/MS), showed more than 100 volatile compounds, most of them present in all honey samples but with quantitative variation. Besides many furfural derivates, 3-methylbutanoic acid was the main volatile compound found in most of honeys. Also the presence of 2- and 3-methylbutanal and pheynalcetaldehyde confirmed the typical buckwheat aroma of some studied samples, corroborating physicochemical data. The HPLC phenolic profile was similar across the samples and phydroxybenzoic and p-coumaric acids proved to be the main components

Botanical traceability of unifloral honeys by chemometrics based on head-space gas chromatography

The botanical origin of honey is subjected to severe controls by Food Control Institutions, both for health protection and for frauds prevention. The complexity of honey makes it very difficult to verify the botanical origin. Among the available validated methods, sensory analysis and melissopalynology are the most widely employed. These methods require a long time and deep consolidated expertise. To shorten analysis time while simplifying the analytical procedure, head-space flash gas chromatography was applied in the present study. Chromatographic peak areas were processed by chemometrics (in particular principal components analysis and linear discriminant analysis). Three hundred and thirty-nine honey samples from twelve categories of unifloral honey were analyzed: acacia, citrus, chestnut, thistle, tree heath, eucalyptus, sunflower, rhododendron, lime, French honeysuckle, fir honeydew, and wood honeydew. Each sample was a priori classified by sensory analysis. The multivariate models were validated by cross validation and test-set validation, with predictive abilities always higher than 80%: good results were obtained both in calibration and in prediction mode, showing a good agreement between this new approach and the traditional one for the determination of the botanical origin of honey

A review of methods for honey sensory analysis

Sensory analysis of honey may be used as a complement to physico-chemical and pollen analyses. It is used to confirm quality, verify the absence of defects, evaluate the conformity to established sensory profiles of unifloral honeys and also to understand consumer preferences. This paper will present a guide to sensory analysis methods for assessing the organoleptic properties of honey and the general procedures required to evaluate them. The standards for honey sensory analysis were developed in reference to specific scientific articles or ISO standards. General requirements for tasting procedures are defined by controlled experimental protocols regarding the design of test booths and best prac- tice for storage, preparation and presentation of honey samples. The assessors should be selected and trained for each method. They must follow the tasting procedures and rules when evaluating and reporting the visual, olfactory, olfac- tory-gustatory and tactile characteristics of honey (including their intensity) and confirm the absence of defects. Two methods for descriptive analysis are reported: the semi-quantitative method which uses detailed descriptors for visual, odor and flavor, and the profile method which employs twelve descriptors related to the botanical origin and whose intensity is scored using a horizontal line scale of 10 cm. Assessment of conformity evaluates a honey\u2019s conformity to the botanical origin and the absence of defects. Also the profile method may be used to evaluate the conformity of uni- floral honey to established sensory standards and to measure the intensity of the attributes

Italian propolis composition in term of geographical origin

Italian’s Propolis is a product rich in flavonoid aglycones (flavones and flavanones), phenolic acids and esters of phenolic acids. This composition is characteristic for propolis produced in Europe. However, Italy is marked by three prevailing climatic zones : Mountain, Continental and Maritime which select areas with different flora and consequent botanical plant sources. Poplar’s buds are known to be the main source of propolis for honey bees, but poplar trees do not grow at high altitude where there are mainly deciduous beech forests or coniferous forests and on the other hand along the coast the vegetation is compoused by Mediterranean scrub and shrubs. The purpose of this study was to evaluate the different composition of propolis from different Italian areas and observe the profile of phenolic acids and flavonoids. Several samples of propolis were collected along Italian's country, including islands, in 2013. It was not been requested to beekeepers a specific way of picking up but only they had to ensure that the hives were of permanent stations in order to correlate closely the samples to the territory of origin. Ethanol extracts of propolis (EPP) was obteined by soxtleth method according to in accordance to argentina regulation IRAM - INTA 15935-1. Samples were previously defined in their resinous percentage composition in relation to the wax and mechanical impurities. The resinous fraction was then analyzed and evaluated. The molecules were chosen in accordance with the data reported in literature, being these the most representative for the European propolis. About twenty molecules of phenolic acids and flavonoids were quantified with the external standard method. Separation and quantification of the compounds was performed by a chromatography with mass spectrometer detector (HPLC-Q/MS-MS ). The analysis on the samples was performed also by spectrophotometric techniques. (Finally, the bioactive properties of resinous extract were Studied also in terms of reducing power and radical scavenging effect). The data were then processed by statistic analysis to identify groups and connections with the geographical and climatic zone of origin

Determination and changes of free amino acids in royal jelly during storage

Free amino acids (FAAs) in royal jelly (RJ) were determined and their identification was confirmed with mass spectrometric detection (GC-MS). The presence of D-aminoacids was evaluated using GC with a chiral column. The total FAA content was 7.3 mg/g RJ on average; the major FAAs were proline, lysine, glutamate, b-alanine, phenylalanine, aspartate and serine. The concentration of FAAs of the D-series was below the detection limit of the method (0.1 mg/g RJ) in all the samples. The FAA fraction was monitored in RJ frozen immediately after sample collection (control) and in aliquots of the same sample stored at two different temperatures (room temperature and 4 °C) for different time intervals (3, 6 and 10 months). The FAA content was constant throughout storage at 4 °C. However, at room temperature, proline and lysine increased after three months to 6.8 and 3 mg/g, respectively and then decreased after 6 and 10 months to 3 and 1 mg/g