Honey Color Research Articles

Physicochemical and bioactive properties of six honey samples from various floral origins from Tunisia

The present study was undertaken to determine the physicochemical, biochemical, and antioxidant activities of Tunisian honey samples. All the extracted honey samples appeared to conform to the European Legislation (EC Directive 2001/110) for all parameters. Mint honey, for instance, possesses significant pH value (p<0.05), invertase activity, water, and protein contents. In addition, this study demonstrates that the color of the Tunisian honeys is highly variable and ranges from pale yellow to dark brown. The total phenolic, flavonoid and carotenoid contents significantly vary (p<0.05). The highest values were found in mint honey, which has a very dark color. Correlations between the analyzed parameters are statistically significant (p<0.05). The DPPH radical scavenging activity of rosemary honey was determined as lower (p<0.05) than the other analyzed honey samples. Yet, the highest activity was detected in mint honey. The results suggest that Tunisian honeys could be beneficially used as a functional or nutraceutical substance as they prevent or moderate oxidative stress-related diseases.

Application of digital images to determine color in honey samples from Argentina

Honey color is the first quality attribute evaluated by consumers and is an important sensory property in the beekeeping market. The most commonly used method for color determination is based on optical comparison, employing a Pfund colorimeter. This method is laborious, time consuming and is based on a subjective assessment. In order to obtain a fast and objective measurement of honey color, an analytical method based on digital images analysis combined with multivariate calibration (Partial Least Squares) was developed. Three color models, RGB (red–green–blue), HSB (hue–saturation–brightness) and Grayscale, were used to analyze the digital images. The optimum results were obtained by using HSB color model (r2=0.97 and RMSEP=2.46), indicating that the digital image analysis combined with multivariate calibration is an excellent strategy for quantifying color in honey samples.

Botanical origin, colour, granulation, and sensory properties of the Harenna forest honey, Bale, Ethiopia

In this study, the Harenna forest honey samples were investigated with respect to their botanical origin, granulation, colour and sensory properties. Sixteen honey samples were collected from two representative sites (Chiri, C, and Wabero, W) using random sampling techniques. Botanical origin was investigated using qualitative pollen analysis by counting 500 pollen grains using harmonised methods of melissopalynology. Granulation, colour, and sensory properties of honey were determined by visual observation, using Pfund grader, acceptability and preference tests, respectively. Honey samples were also tested for tetracycline. Honey obtained from Wabero is originated dominantly from Syzygium guineense while Chiri was multifloral. The colour of honey ranged from 34 to 85 with light amber and extra light amber colours. The honey samples were free from tetracycline residue and form coarse granules slowly. Significant variation (p>0.05) in sensory preference and acceptability tests not observed due to hive types and locations.

Effect of filtration on colour, antioxidant activity and total phenolics of honey

82 Honey samples harvested in 2009 and 2010 flowering seasons were investigated in order to examine the influence of filtration on colour, antioxidant activity and total phenolics content. In unfiltered honey samples the total phenolics content varied between 40.5 and 177 mgGAE/100 g. The average antioxidant activity ranged from 47.2 to 83.4% when measured with DPPH and from 6 to 79% once measured with ABTS+. The results indicated that filtration had no significant effect on the above-mentioned parameters, however they were found to depend on the types of honey.

Comparison of methods for determining the color of Chilean honeys and the relationship of color with botanical origin in central Chile

M.J. Martin, C. Fredes, G. Nunez, R. Ginocchio, and G. Montenegro. 2014. Comparison of methods for determining the color of Chilean honeys and the relationship of color with botanical origin in central Chile. Cien. Inv. Agr. 41(3): 411-418. The color of honey has special relevance in the international market, as different markets demand specific colors of honey. Chile has very diverse native and exotic flora, which are used by bees (Apis mellifera) to produce a range of honey types, including honeys of different colors. In this context, determining the relationships between color and botanical origin among Chilean honeys is very relevant. The objectives of the present study were to compare three methodologies for determining color in Chilean honeys (Pantone®, optical density (OD), and Pfund) and to define the relationship between color and botanical origin of the characterized honeys. The most common honeys from the Libertador Bernardo O’Higgins Region (VI Region) of Chile were Galega officinalis, Quillaja saponaria, and Retanilla trinervia unifloral honeys, all of which have lighter colors than internationally described. Both the OD and Pfund methods could identify significant differences between dominant species; specifically, these methods were able to discriminate between G. officinalis and Q. saponaria honeys and between G. officinalis and R. trinervia honeys. The OD and Pfund methods revealed that honeys of G. officinalis (A530 nm: 0.93 and 95.53 mm Pfund) were darker than those of Q. saponaria (A530 nm: 0.42 and 80.66 mm Pfund) and R. trinervia (A530 nm: 0.35 and 73.41 mm Pfund). Although the three methods for determining the color of Chilean honeys had different efficacies, the OD method was able to discriminate among dominant species and honey types. Significant correlations among the dominant species were found for Chilean honeys from the Libertador Bernardo O’Higgins Region using both the OD and Pfund methods.

Effect of country origin on physicochemical, sugar and volatile composition of acacia, sunflower and tilia honeys

The aim of this study was to evaluate the influence of country (Spain, Romania, and Czech Republic) and botanical origin, on the physicochemical (HMF, diastase activity, moisture content, electrical conductivity), color (Pfund scale and CIEL*a*b*), principal sugars (glucose, fructose and sucrose) and volatile composition of acacia, sunflower and tilia honeys. PCA analyses considering these variables showed that honey type had a far greater influence on the differentiation of samples (above all due to the presence of certain volatile compounds such as carvacrol and α-terpinene for tilia honey; α-pinene and 3-methyl-2-butanol for sunflower honey, and cis-linalool oxide for acacia honey) than geographical origin. Discriminant models obtained for each kind of botanical honey (classified 100% for acacia and tilia honeys and 93.8% for sunflower of the cross-validated cases) confirmed that differentiation of honeys according to their country was mainly based on volatile compounds (for instance: 2-methyl-2-butenal and 2-methyl-2-propanol, for acacia honeys; 1-hexanol and α-pinene, for sunflower honeys and 3-methyl-1-butanol and otrienol, for tilia honey) and to a lesser extent on certain physicochemical parameters such as diastase, sucrose and conductivity, respectively. Correct classification of all samples was achieved with the exception of 10% of the sunflower honeys from the Czech Republic. The results suggest that the presented models are potentially useful tools for the classification of acacia, sunflower and tilia honeys according to the country of origin.

Effect of postharvest storage conditions on the colour and freshness parameters of raw honey

SummaryThe influence of temperature (25, 30, 35 and 40 °C) and storage time (up to 62 or 104 days) on colour; hydroxymethyl furfural (HMF) content; and diastase index (ID) of citrus, rosemary, eucalyptus, polyfloral and honeydew honey was evaluated. Decreases in luminosity, whiteness index, hue and chroma with the increase in temperature and storage time were observed to different extents depending on the botanical origin of the honey. At all temperatures, the highest values of chromatic parameters throughout the whole period of storage corresponded to citrus honey. Honeydew honey showed the lowest values and the fewest colour differences. Principal component analysis explained 89% of the variations. PC1 (73%) separated honey types at lower temperatures in terms of colour parameters. PC2 (16%) described variations in HMF and ID in relation to storage conditions. Honey type had a much greater influence on HMF, ID and colour than storage conditions. The evaluated postharvest treatments did not alter the characteristic colour of each type of honey as long as the commercial requirements for freshness parameters were met.

Assessment of Colour Intensity, Polyphenol Contents and Antibacterial Capacity of Sahara Honeys Produced by Apis mellifera

Sahara honey samples from Algeria were screened for total phenolic contents by Folin Ciocalteau method and colour characteristics.Two different assays were performed to evaluate the antibacterial capacity of the honey samples: agar-well diffusion and Growth inhibition %.Total phenolic content varied from 0.620 to 1.044 mg/100 g honey as gallic acid equivalent.The colour of the Sahara honeys, analysed in this study was very variable and ranged from pale yellow to dark brown.In the antibacterial tests using two bacteria, Staphylococcus aureus and Pseudomonas aeruginosawere moderately sensitive to honey samples. There was no correlation between antibacterial activity and total phenolic contents

Total Phenol, Antioxidant Activity, Flavonoids, Anthocyanins and Color of Honey as Affected by Floral Origin Found in the Arid and Semiarid Mediterranean Areas

Honey samples representing 12 different Mediterranean floral sources in Jordan were investigated for their phytochemical compounds and color. The floral composition (% pollen), total phenolics, total flavonoids, antioxidant activity, anthocyanins and color varied between locations. Total phenolics were highest (86.3 mg GAE/100 g) in the multifloral summer honey from Sarrout location and lowest (33.7 mg GAE/100 g) in the early spring harvest from the Jordan Valley. The flavonoid, anthocyanins and antioxidant activities were highest in summer honey from Umm Alyanabea location (4.6 mg/100 g, 4.1 mg/100 g and IC50 = 24.5 mg/mL, respectively) and were lowest in the early spring honey harvest from the Jordan Valley. The colors of Jordanian honey were visually noticeable, varying from yellowish, yellowish green to darker colors. Significant differences existed in the phytochemical compounds in different honey samples from different Mediterranean areas in Jordan. These differences mainly depended on floral sources. Practical Applications Honey is a natural product produced primarily from the nectar secreted by flowering plants gathered and processed by the honeybee (Apis millifera). It is an important and unique food product containing bioactive compounds derived from plant nectar or added by bees, and these compounds are known to act as natural antioxidants that play an important role in food preservation and human health through combating damage caused by oxidizing agents. Honey collected from different nectar of plant flower species contains different levels of phenolics that possess antioxidant activity, so different honey properties were expected since the composition of active compounds in honey from different locations should be different. Therefore, this study was conducted to evaluate the bioactive compounds and color of honeys obtained from various plant vegetations in the arid and semiarid Mediterranean areas in Jordan.

Potential application of machine vision to honey characterization

Characterization of honey is an important issue in the food industry and of interest to the consumers. This paper deals with the application feasibility of machine vision for the characterization of honey and shows how it can be employed in practical use by the industry. There is a correlation between honey color and its floral origin and some chemical parameters which could be properly used for characterization of honey. This may be accomplished by employing image analysis for honey color quantification as well as the algorithms that are available for classification and prediction of chemical parameters of foods.

Evaluation of physico‐chemical properties, trace metal content and antioxidant activity of Indian honeys

SummaryIn this study, effect of plant sources viz. Gossypium hirsutum, Coriander sativum, Murraya koenigii and Dalbergia sisso on twelve physico‐chemical properties, phenolic content, flavonoids content as well as on trace mineral (Fe, Cu, Ni, Mn, Cd and Pb) contents of honey were investigated and compared. All the physico‐chemical values were in the range of approved limits of European Commission Regulation and the source of honey had a significant (P &lt; 0.05) effect on physico‐chemical properties, phenol content, flavonoid content and trace mineral content. The results of positive correlations between physico‐chemical properties (colour and antioxidant properties) and compositional components (phenols and flavonoids content) established that antioxidant properties were dependent on source of honey rather than on colour of honey. Pattern recognition methods such as principal component analysis and linear discriminate analysis were performed to classify honey on the basis of physico‐chemical properties, phenolic content, flavonoids content and trace metal content. The variables proline and lead exhibited higher discrimination power.

Multi-elemental composition and physical properties of honey samples from Malaysia

The elemental profiles of six honey samples from Malaysia had been constructed using the data obtained from both ICP-AES and ICP-MS. Potassium and sodium were the most abundant minerals covering from 69.3–78.6% and 14.1–28.7%, respectively. The ratio of potassium to sodium was more than one. Even though the minerals and trace elements composition varied dependent on the type of honey samples, there was no statistically significant difference between the analysed honey samples, namely tualang, gelam, acacia and a few forest honeys based on two-factor ANOVA and cluster analysis. The total element content of honey samples were strongly correlated with the electrical conductivity, but only have moderate correlation with the ash content and honey colour based on the regression analysis. PCA result on the available elemental data from worldwide honeys, including honey samples from Malaysia revealed that potassium and sodium were the mineral markers to distinguish honey origin. Both tualang and gelam honey samples from Malaysia have close mineral profile with sesame honeys from Egypt and multifloral honeys from India, whereas forest honeys Malaysia were near to avocado honeys from Spain and multifloral honeys from India.

Determination of the hydrophobic fraction of Ca, Fe, Mg and Zn in dark color honeys using solid phase extraction and flame atomic absorption spectrometry

In this study, the hydrophobic fraction of Ca, Fe, Mg and Zn in dark honeys was assessed by means of solid phase extraction using silica gel based material with monomerically bonded phenyl active groups (Discovery® DSC-Ph tubes). It was found that Fe is associated with this fraction, likely polyphenolic compounds, to the highest degree. The contribution of the hydrophobic fraction to the total content of this element in analyzed honeys accounted for 7-43%. The reliability of these results was verified using for solid phase extraction silica gel based material with polymerically bonded octadecyl active groups (SupercleanÔ ENVI DSC-18). Additionally, a strong positive correlation was established between the concentration of Fe in the hydrophobic fraction assessed and the optical density of dark honeys, indicating a possible contribution of blue complexes of this metal with phenolic substances to the overall color of honey.

Formulation Development of Gel-Based Lipstick Containing Longan Honey and Natural Color Extracted from Sappan Wood and Roselle

Nowadays, natural cosmetics have become more popular and acceptable to consumers than the chemically synthesized ones. In this study, we have developed a new formulation for gel-based lipstick by using the mixture of Longan honey and natural color extracts from Sappan wood (Caesalpinia sappanL.) and Roselle (Hibiscus sabdariffaL.). The final products were analyzed for their physical and antioxidant properties. The new formulated lipstick showed good antioxidantproperties ranging from IC500.25±0.12 to 5.12±0.24 mg/ml when tested by using DPPH radical scavenging method. Stability test was also conducted by several heating and cooling cycles. The physical characters (i.e. viscosity and pH) were also examined and recorded.

Physico-chemical indicators and identification of selected Slovak honeys based on colour measurement

The aim of study was to characterize 52 samples of Slovak honeys of six types (multifloral, acacia, rape, honeydew, forest and mixed). Physico-chemical analysis of honey included the water content, free acidity, pH, water activity, electrical conductivity, and hydroxymethylfurfural (HMF) content. In addition, the colour of honeys was measured using spectrophotometer and Commission Internationale de I`Eclairage method (CIE L*a*b*); four types of honey were used for identification: multifloral, acacia, rape, and honeydew. Mean values of physico-chemical indicators were as follows: water content 16–21%, acidity 6–42 mekv·kg-1, pH 3.68–5.15, water activity 0.505–0.667, electrical conductivity 0.155–1.585 mS·cm-1 and HMF content 0.17–78.5 mg·kg-1. The highest HMF content was found in forest honey with one sample above the limit established by Council Directive 2001/110/EC. The colour of Slovak honeys analysed in this study was very variable and ranged from pale yellow to dark brown. Differences of physico-chemical indicators and colour of honey samples were found to be significant (P &lt; 0.05). The CIE L*a*b* methods can be used for identification of selected honey samples. This is the first similar study on Slovak honey.

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.

Determination of the Physical Characteristics of Food Raw Materials by Spectrophotometry - The Example of Honey

The paper presents changes in the color of 10 selected types of honey during storage. The measurements were performed using a MiniScan XE Plus spectrophotometer (HunterLab). The color of honey was described based on L*a*b* coordinates. The values of hue h* and chroma C* were also calculated. Until day 14 of storage. no statistically significant ( p= 0.01) changes in the color of crystallized oilseed rape honey, liquid multifloral honey and crystallized multifloral honey were noted. The color of the remaining seven honey types started to change on the first day of storage.

Características físico-químicas de méis produzidos em favos de diferentes idades

Honey color is a characteristic related to the flower source and plays a major role on consumers buying preference. When finished, honey is placed in wax honeycombs that are composed mainly by hydrocarbons, esters and a small percentage of fatty acids and alcohols that give to wax the plasticity and ability to absorb several kinds of elements. The consecutive comb reutilization might transfer pigments to honey that, in turn, can alter honey final characteristics. In the present study the objective was to evaluate the influence of comb reutilization on honey physico-chemical and color characteristics. The experiment was carried out using randomized blocks with four treatments and six repetitions. Each hive was considered a block. The treatments consisted of boxes with sheet of alveolated wax and honeycomb with one, two or three years of usage, totaling 24 boxes. Honey samples were analyzed by diffuse reflectance spectrophotometry and the physico-chemical properties were analyzed by laboratory standard tests. The diffuse reflectance, total sugar, pH, acidity and ash did not varied significantly among treatments (p > 0.05). Honey color produced in honeycomb with different years of use was similar amongst treatment; however, the honey produced in sheets of alveolated wax had clearer color and less sugar content.

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.

Threatened fishes of the world: Clarias batrachus (Linn. 1758)

Common name: Magur, Walking Catfish. Conservation status: Vulnerable (CAMP 1998). Identification: Brownish black in colour. Elongated body with round abdomen and laterally compressed tail. Head with two depressions. Upper jaw slightly longer than lower. The mouth is wide and terminal. Four maxillary and four mandibular barbells. The dorsal fin and anal fin both long, reaching caudal base. Caudal fin homocercal, separated from dorsal and anal fin. D 62–76, P 1/8–11, V 6–7, A 45–58, C 14–17. Illustration by S. Mahali. Distribution: It is native to Indian sub-continent (Jayaram 1981). Habitat and ecology: Inhabits swampy areas and water bodies adjacent to paddy fields. Omnivore with broad feeding habits at different life stages (Hora and Pillay 1962). Reproduction: It breeds in second year of life during the monsoon (June–August) in vegetation under embankments. Parental care exists. The fecundity varies from 4000– 5000 (100 g females) and increases with fish size. The honey colour eggs are adhesive. Threats: Declining population is due to high fishing pressure and habitat loss from rapid urbanization. Conservation action: The Central Institute of Freshwater Aquaculture, India has started working intensively on its propagation and feed development (Sahoo et al. 2005, 2008; Giri et al. 2005). Seven other national Institutes are presently involved on its artificial propagation, sponsored by Indian Council of Agricultural Research, New Delhi. Recommendations: Mass production through hatchery operations, rearing young in natural waters and aquaculture of this species are necessary to restore populations. Remark: Ironically, it is recommended for monoculture in south-east Asia due to its high production potential and market demand. Environ Biol Fish (2010) 88:85–86 DOI 10.1007/s10641-010-9627-8