Physical, biochemical and antioxidant properties of some Indian honeys

The study was intended to characterise the physicochemical and antioxidant properties of some commercial brands of Indian honeys. All the samples showed considerable variations with reference to their level of total phenolics, protein, radical scavenging activity, ascorbic acid equivalent antioxidant content (AEAC) and ferric reducing antioxidant potential (FRAP). Comparative studies of Indian honeys indicated the strong correlation between proline content and AEAC as well as 2,2-diphenyl-1-picryl-hydrazyl (DPPH) scavenging activity whereas phenol content was strongly correlated with FRAP values. Thus, overall antioxidant activity seems to be contributed by proline and phenol contents. Besides these major factors, colour pigments (ABS₄₆₀) were also found to contribute significantly to the overall observed antioxidant activity.     

Major flavonoids of Argentinean honeys. Optimisation of the extraction method and analysis of their content in relationship to the geographical source of honeys

In the present research we optimised an extraction procedure for the flavonoid aglycones: myricetin, quercetin and luteolin from honeys (as natural biological matrices), based on Amberlite XAD-4 resin followed by HPLC quantification. In addition, honeys from three geographical regions of Argentina were analysed with regard to the contents of these flavonoids. The extraction procedure was optimised for XAD-4 resin considering: resin/honey ratio, elution volume to desorb flavonoids and colour intensity of honeys. Differences in flavonoid recoveries were observed depending on the colour intensity. The flavonoid aglycones contents, in accordance with differences in geochemical characteristics and typical vegetation, varied with the geographical origin of honeys. The results obtained allowed us to consider these three flavonoids as chemical markers for the phytogeographical origin of honeys. In the case of monofloral honeys, the contribution of each one of the flavonoids was associated with the presence of a dominant pollen kind in these samples.     

The relationship between the content of Maillard reaction-like products and bioactivity of Canadian honeys

Honey possesses antioxidant and antibacterial activities; however the compounds that are responsible for these activities are still under investigation. To determine whether there are common features/compounds that underlie the antioxidant and antibacterial activities, 20 Canadian honeys were analysed using the oxygen radical absorbance capacity (ORAC) and the broth micro-dilutions assay, respectively. Principal component analysis revealed the highest correlation between ORAC and Maillard reaction-like products (MRLP) (R = 0.938, p < 0.0001). In addition, the extremely significant correlations between ORAC, MRLPs, phenolic content and honey colour may suggest that these compounds represent the same chemical entity and exert their antioxidant activity while being part of a higher molecular weight structure. Moreover, the antioxidant activity and MRLPs were also the dominant variables contributing to the antibacterial activity against Escherichia coli (R = 0.737, p < 0.0001 and R = 0.65, p < 0.002, respectively) however no such correlation against Bacillus subtilis. In conclusion, MRLPs in honey appear to underlie the antioxidant and partially the antibacterial activity against E. coli.     

Physico-chemical and bioactive properties of different floral origin honeys from Romania

In this study, we investigated and compared the physico-chemical properties (moisture, colour, ash, and sugars content) as well as total phenols, total flavonoids and antioxidant activity of several honey samples (24) collected from different regions of Romania. The physico-chemical values were in the range of approved limits (conforming to EU legislation); excepting the monosaccharide values for one sample (T2). For this sample, the other values were within legislation limits. The results obtained showed that the most valuable honey is the honeydew one. Correlation between RSA and total phenols and total flavonoids, respectively, was determined, and a positive correlation was found. This study demonstrates remarkable variation in antioxidant properties and content of total phenols in honey, depending on its botanic or geographic source.     

Evaluation of antioxidant activity and total phenolics of selected Czech honeys

Honey serves as a good source of natural antioxidants, which are effective in reducing the risk occurrence of heart disease, cancer, cataracts, different inflammatory processes and immune-system decline. In the fresh selected Czech honey samples originated mainly from the region North Moravia antioxidant activity and total polyphenol content were determined. A total of 40 honey samples (multifloral, lime, rape, raspberry, mixture and honeydew honeys) native to different stations gained in the period from May by August year 2006 were analysed. Total phenolics (TP) content was determined by the modified Folin-Ciocalteau method [TP was expressed as mg of gallic acid equivalent (GA eq.) per kg of honey]. For evaluation of the antioxidant activity (AOA) three different methods were used, the ferric reducing antioxidant power (FRAP) assay, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and the 2,2′-azinobis(3-ethylbenzothiazolin)-6-sulfphonate (ABTS) assay. AOA was expressed in mg ascorbic acid equivalent (AA eq.) per kg of honey. The results indicated that TP and AOA in Czech honey varied greatly between the honey kinds, location and time of the harvest. Average TP ranged from 89.9 mg GA eq. kg^-1 in lime honey to 215.2 mg GA eq. kg⁻¹ in honeydew honey. Antioxidant activity determined by the DPPH, ABTS and FRAP methods was lowest in floral honeys. The highest values were obtained for honeydew and mixture honeys. ABTS and FRAP assays have been shown to be the optimal methods for AOA determination in honey. A positive linear correlation between AOA and TP was observed (in FRAP assay R² = 0.852). It indicates that phenolics are one of the main components responsible for antioxidant behaviour of honey. The obtained results support and extend complete knowledge about the content of bioactive phenolics and antioxidant activity in the Czech honeys.     

Phenolic content,antioxidant and physico‐chemical properties of Sardinian monofloral honeys

In this study, fifty‐one monofloral Sardinian honeys from ten various floral origins were screened for their phenolic content, antioxidant activity, colour and electrical conductivity. The total phenolic amounts have been evaluated by Folin–Ciocalteu method, whereas quantification of several phenolic compounds (phenolic acids and flavonoids) has been carried out by HPLC‐DAD technique. The richest sample in phenolic compounds resulted strawberry tree honey with about 40 mg GAE/100 g, as well FRAP test and DPPH˙ test confirm that antioxidant activity of strawberry tree honey extract exceed both honey extracts and synthetic antioxidants like BHA and BHT. Among the studied phenolic compounds a total of five phenolic acids (ferulic, syringic, trans‐cinnamic, chlorogenic and p‐hydroxycinnamic) and nine flavonoids (catechin, kaempferol, rutin, quercetin, luteolin, apigenin, galangin, pinocembrin and pinobanksin) were identified. Our results show good correlations between total polyphenol amount and antioxidant activity and between colour and electrical conductivity.     

Microbiological and chemical characterization of honeys from central Argentina

The characterization of some honey samples from southern Córdoba (Argentina) was carried out on the basis of their microbiological (Clostridium, fungi and yeasts), physical (colour) and chemical (carbohydrates, HMF, water and free acidity) analysis. The results showed that honeys produced in this region are of good quality. HMF content and free acidity values were mostly low, indicating honey freshness. Most of the samples contained less than 20% water. Glucose and fructose accounted for more than 60% of the weight. The amount of yeast and fungi found in the honey samples was less than 1 × 10² CFU/g. Low quantities of vegetative cells and spores of Clostridia were found in some honey samples. A standardization and a rationalization of beekeeping techniques throughout southern Córdoba may further improve honey quality, and ensure it over the years.     

Phenolic profile and antioxidant properties of Polish honeys

The phenolic components of honeys have great participation in their nutritional value and antioxidant activity. Moreover, phenolic components are promising markers for the determination of botanical and geographical origin of honey. The purpose of the present work was to study the antioxidant activity and profiles of phenolic acids and flavonoids of honeys of various origins. The total phenolic content of honeys varied from 4.46 to 15.04 mg of gallic acid equivalents per 100 g of product and the total phenolic acid content determined chromatographically varied from 201.05 to 2089.08 μg per 100 g of product. Buckwheat honey exhibited the highest antioxidant activity and contained the highest total phenolic amount, whereas rape honey exhibited the lowest values in this respect. Moreover, the buckwheat honey contained the highest amount of phenolic acids. There were significant linear correlations between total phenolic content and antioxidant activity of honey extracts in the reaction with DPPH^? (1,1‐diphenyl‐2‐picrylhydrazyl) and ABTS^{? +} (2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid)) free radicals. In most samples, p‐coumaric acid was the dominant phenolic acid (39.1–677.2 μg per 100 g). The honeys also contained considerable amount of gallic acid (6.0–913.8 μg per 100 g). Among flavonoids naringenin was predominant in the most studied honey samples.     

The recognition of high molecular weight melanoidins as the main components responsible for radical-scavenging capacity of unheated and heat-treated Canadian honeys

As the Maillard reaction is known to occur in heat-treated foods, unheated and heated honey samples were subjected to the activity-guided fractionation and size-exclusion chromatography to compare the degree of browning, radical scavenging activity (ORAC) and molecular size of the fractions obtained. Heat-treatment increased browning in the fractions of light- and medium-coloured honeys (p < 0.002), accelerated the formation of high molecular weight melanoidins (85–232 kDa) and significantly increased ORAC values (p < 0.0001). In contrast, melanoidin content and ORAC decreased in the fractions of heat-treated dark buckwheat honey (p < 0.001). Unheated dark honey contained a significantly higher amount of melanoidins than other honeys (p < 0.007). Together, results showed that at low initial concentration of melanoidins, heat-treatment accelerated formation of new melanoidins and increased ORAC, while at high concentration it caused decrease and a reduction of radical scavenging activity. This study emphasises the importance of non-enzymatic browning in the prediction of the antioxidant pool in thermally processed honeys.     

Presence of furosine in honeys

Nineteen commercial samples (with a shelf‐life of 2 years) and two artisanal samples (freshly collected and stored for 1 year respectively) of Spanish honeys were analysed for pH, protein content and furosine content. Most of the samples had pH values and protein contents within the limits reported in the literature. The presence of furosine was confirmed by comparison of its retention time with that of a furosine standard and by HPLC–MS. The level of furosine in the samples studied ranged from 4.32 to 13.62 g kg^?1 protein. The lowest furosine value was observed in the freshly collected artisanal sample. Heat treatment under severe conditions (90 °C for up to 135 min) increased the furosine content from 4.43 to 14.38 g kg^?1 protein. The results show that furosine seems to be a promising indicator to detect overheating during honey manufacture. © 2001 Society of Chemical Industry     

Evaluation of bioactive properties of peptide isolated from Exocoetus volitans backbone

The aim of this study was to evaluate antioxidant, antiproliferative and antimicrobial properties of flying fish (Exocoetus volitans) backbone hydrolysed by three different enzymes namely papain, pepsin and trypsin. The in vitro antioxidant potencies of hydrolysates and purified peptides against 1, 1‐diphenyl‐2‐picrylhydrazyl, superoxide and hydroxyl radicals were evaluated by electron spin resonance spectroscopy. The peptic protein hydrolysate showed maximum free radical scavenging potential and lipid peroxidation inhibition and was further purified by DEAE XK 26/20 anion exchange chromatography followed by G‐25 gel permeation chromatography. The amino acid composition of potent purified fraction was determined by HPLC, contains essential and nonessential amino acids with glutamic acid (24.10%), lysine (23.62%), glycine (12.05%) and threonine (10.41%) as the dominant amino acids. The potent purified fraction was tested for cell cytotoxicity on Vero and Hep G₂ cell lines. It was found that fraction IIIb did not show any cytotoxic effect for Vero cell lines and exerted a significant antiproliferative effect on Hep G₂ cell lines.     

Physicochemical characteristics of minor monofloral honeys from Tenerife,Spain

Physicochemical parameters (moisture, water activity, electrical conductivity, colour, hydroxymethyl furfural, acidity, pH, proline, diastase and invertase) and sugar composition (fructose, glucose, sucrose, maltose, isomaltose, trehalose, turanose and melezitose) were determined in 85 honeys belonging to nine minor monofloral honeys such as avocado (Persea americana), barrilla (Messembryanthemum crystallinum), heather (Erica arborea), agave o pitera (Agave americana), poleo (Bystropogon origanifolius), relinchón (Hirstfeldia incana), tedera (Aspalthium bituminosum), malpica (Carlina xeranthemoides) and oregano (Origanum virens) from Tenerife in order to typify them for the first time. Most of the studied honeys are characterized because their specific pollens are under-represented. All the honey samples showed values of all the parameters determined within the legally established intervals. All the physicochemical and sugar composition parameters, with the exception of diastase, presented significant differences in the mean values between the honeys analyzed. Applying univariate statistical analysis, the following parameters (moisture, acidity, electrical conductivity, fructose, sucrose and melezitose) allow to distinguish all the types of honeys studied without overlap. Heather and avocado honeys showed the most differential physicochemical characteristics with respect to the rest of monofloral honeys.     

Physicochemical properties,antioxidant activity and cellular protective effects of honeys from southern Africa

The southern Africa region is a region of unique floral biodiversity; this study was undertaken to address the limited knowledge regarding the physiochemical, antioxidant activity and the ability of these honeys to protect biomolecules and cells against oxidative damage. The physicochemical properties, total polyphenolic and flavonoid content (TPC and TFC), catalase and antioxidant activity (DPPH, TEAC, and ORAC assays) of 13 representative honey samples was determined. Biological and cellular protection was investigated using the erythrocyte haemolysis, the pBR322 plasmid, as well as the dichlorofluorescein diacetate (DCFH-DA) assays in SC-1 and Caco-2 cells. High TPC, TFC, catalase and antioxidant activity was obtained, and all honeys protected DNA, erythrocytes and cells in vitro. Colour, TPC, TFC and antioxidant activity correlated well but no correlation was seen between these parameters and catalase activity, biological and cellular effects. Nevertheless, honeys with high catalase activity and/or are dark in colour with high TPC, TFC and/or antioxidant activity did show the highest degree of biological and cellular protection.     

Trace element levels in honeys from different regions of Turkey

A survey of 25 honey samples from different botanical origin, collected all over the Turkey was conducted to assess their trace element contents. The aim of this study was to determine the levels of cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr), zinc (Zn), aluminium (Al) and selenium (Se) in honey samples from different regions of Turkey. Trace element contents were determined by a flame and graphite furnace atomic absorption spectrometry technique after dry-ashing, microwave digestion and wet-digestion. The accuracy of the method was corrected by the standard reference material, NIST-SRM 1515 Apple leaves. The contents of trace elements in honey samples were in the range of 0.23–2.41 μg g⁻¹, 0.32–4.56 μg g⁻¹, 1.1–12.7 μg g⁻¹, 1.8–10.2 μg g⁻¹, 8.4–105.8 μg kg⁻¹, 2.6–29.9 μg kg⁻¹, 2.4–37.9 μg kg⁻¹, 0.9–17.9 μg kg⁻¹, 83–325 μg kg⁻¹ and 38–113 μg kg⁻¹ for Cu, Mn, Zn, Fe, Pb, Ni, Cr, Cd, Al and Se, respectively. Iron was the most abundant element while cadmium was the lowest element in the Turkish honeys surveyed. The results showed that trace element concentrations in the honeys from different regions were generally correlated with the degree of trace element contamination of the environment.     

Evaluation of Several Romanian Honeys Based on their Palynological and Biochemical Profiles

In this work, different types of honey were characterized based on their palynological and biochemical characteristics. A mellisopalynological analysis was performed to authenticate the botanical origin of the honey samples. According to this method, the honey types were classified in: acacia (n = 10), linden (n = 10), and rape (n = 10). This article also reports the phenols content, the flavonoids content, and the antioxidant activity of honey samples. The highest level of antioxidant activity was recorded for linden honeys and the lowest for acacia honeys. The multivariate analysis demonstrated to be an important tool in classification and discrimination between different honeys concerning the palynological and biochemical properties.     

Stingless bee honey: Quality parameters,bioactive compounds,health-promotion properties and modification detection strategies

BackgroundHoney is a natural product produced and marketed worldwide by stingless bees and Apis bees. Both these types of honey contain unique and distinct compounds of variable nutritional and biological importance. Stingless bee honey is popular for its distinct sweetness, mixed with an acidic taste, and fluid texture; it has higher added value than Apis mellifera honey. Due to the relatively low output of stingless bee honey compared to Apis mellifera honey, comprehensive data regarding the former is limited. This complex, natural product requires official, international methodologies and standards to be established to serve as a reference for quality control, to prevent adulteration, and to aid marketing purposes.Scope and approachThe article summarises the existing literature regarding the physicochemical parameters, chemical composition, bioactive constituents, biological properties, and modification detection strategies of honey originated from 478 honey samples from 66 different stingless bee species produced worldwide.Key findings and conclusionsStingless bee honey is one of the most complex natural foodstuffs. This type of honey quantitatively possesses a higher moisture content, greater acidity, a slightly lower level of total carbohydrates, and higher levels of antioxidant and biological activities than Apis mellifera honey. This review emphasises that stingless bee honey represents an important innovation for the food, pharmaceutical and cosmetic industries, due to its positive health effects and market potential.     

Premium honeys: Response of sensory panelists

Four honeys and one synthetic ‘honey’ were ranked by 62 panelists for relative acceptability; willingness to buy was ranked after price information was provided. Data were analyzed with the R-index procedure and Friedman ranked sums test. Honey floral source and production location differed. Panelists completed a questionnaire concerning food selection and perception and selection of honey. Instrumental techniques were used to characterize the honeys.

Honey was perceived by these panelists to have a unique flavor and positive image. Alaska wildflower, a fireweed table honey and Alaska fireweed/clover were the most acceptable. Acceptability did not necessarily correspond to willingness to buy. Similar results were obtained from both the R-index and rank sums analyses. The instrumental assessment of color and acceptability were significantly correlated. Generally, characteristics that distinguish premium from table honeys were unimportant in the selection process used by these panelists.     

Biological activities and chemical composition of three honeys of different types from Anatolia

In this study, we investigated and compared some chemical properties and in vitro biological activities of three different types of Turkish honey. The first two honey samples were monofloral from chestnut and rhododendron flowers, collected from the east Black Sea region, and the third sample was the heterofloral form of astragalus (Astragalus microcephalus Willd.), thyme (Thymus vulgaris) and other several mountain flowers, collected from Erzincan in Eastern Anatolia. The chemical properties of the honey samples, such as total moisture, ash, total protein, sucrose, invert sugar, diastase activity, hydroxymethylfurfural content and acidity, were determined. Total phenolics, superoxide radical- and peroxynitrite-scavenging activities, and ferric reducing/antioxidant power measurements were used as antioxidant capacity determinants with ±-catechin, butylated hydroxytoluene, ascorbic acid, and trolox^® used as reference. The antimicrobial activity was studied by the agar diffusion method, using eight bacteria and two yeasts. The mineral contents were also determined by an AAS method. The chestnut flower honey had the highest phenolic content, superoxide radical-scavenging activity and reducing power, while the heterofloral honey sample exhibited the highest peroxynitrite-scavenging activity. The antioxidant activities were also found to be related to the sample concentrations. The mineral content of the chestnut honey was much higher than the others. The samples showed moderate antimicrobial activity against some microorganisms, especially Helicobacter pylori ATCC 49503, Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Candida tropicalis ATCC 13803 and Candida albicans ATCC 10231. The honey samples studied proved to be a good source of antioxidants and antimicrobial agents that might serve to protect health and fight against several diseases.     

Identification of bioactive response in traditional cherries from Portugal

In recent years many studies on cherries have revealed that they are rich sources of bioactive compounds with potential human health benefits. In this work, we evaluated the antioxidant activity and antiproliferative effect in human cancer cells of nine sweet cherries, including two traditional cultivars from Portugal (Saco and Morangão). Results obtained in biological assays, together with the phenolic composition of cherries, were submitted to principal component analysis (PCA) which allowed samples to be grouped in terms of their bioactivity. Saco cherry and two exotic cultivars (Ulster and Lapin) proved to have higher contents of phenolic compounds, highest antioxidant activity and were the most effective in inhibiting human cancer cells derived from colon (HT29) and stomach (MKN45). Correlation of the data obtained showed that anthocyanins were the major contributors to the antioxidant capacity and antiproliferative effect of cherries. Additionally, hydroxycinnamic acids (neochlorogenic acid, chlorogenic acid and p-coumaroylquinic acid), flavan-3-ols (catechin and epicatechin) and flavonols (rutin and quercetin-3-glucoside) also play important roles in protection against oxidative stress.     

Extraction,physicochemical characterisation,and bioactive properties of ink melanin from cuttlefish (Sepia esculenta)

The extracted melanin from Sepia esculenta was characterised by physicochemical properties and biological activities. The yields of melanin were 87.1%, 69.9%, and 62.5% by water extraction, enzymolysis and acidolysis, respectively. The ink melanin contained a characteristic indole structure with irregular spherical structures. Water extraction showed a positive effect on preserving the complete structure of melanin particles based on component analysis, whereas enzymes and acids had destructive effect. Water extraction melanin (WM) exhibited a certain thermal stability and light resistance. WM performed in radical scavenging in a dose-dependent manner. The IC₅₀ of WM for DPPH and ABTS was 99.8 and 104.2 μg mL⁻¹, respectively. WM protected kojic acid and ascorbic acid from light radiation. As the exposure time to light radiation prolonged, the stability of kojic acid and ascorbic acid was preserved. It indicated that melanin might be potentially used as an antioxidant and photo-protectant.