Honey Moisture Research Articles

Experimental Design Factorial Parameters of Honey Water Content Levels to Improve Honey Processing Productivity

In producing honey products, must meet all SNI quality standards (8665:2018), one of which is honey water content of less than 22%. Honey from farmers has a moisture content of more than 22% so the water content must be reduced. On of the technique that use in a company to meet those standard uses a dehumidification system combined with air conditioning and a honey rain device. With the current machine configuration, the required honey moisture reduction process time is 11 days. This study focuses on finding a combination of degrees Celsius temperature factor and relative humidity percentage factor that results in the optimal rate of reduction in water content. The results showed that temperature and relative humidity each had an effect on the rate of decrease in the water content of honey and no interaction effect was found between the factors of temperature and relative humidity on the rate of decrease in the water content of honey. The combination of selected temperature and relative humidity factors, namely 27℃ and 40%, in the most optimal rate of decrease in water content with an average of 0.416667% per hour. When compared with the combination of temperature and relative humidity in the company, namely 30°C and 60%, the selected treatment combination can reduce the processing time for reducing the honey moisture content and increases productivity by 50%.

Honey moisture reduction using several thermal methods and their effects on its quality

Honey is thermally heated at various methods to decrease the moisture content and prolong the shelf life. The heating methods might decrease the quality of honey's physicochemical and biochemical properties. The present study thermally treated the honey with a pasteurizer, evaporator, and dehumidifier. The most thermally affected to decrease the moisture content were treatment by dehumidifier (14.09%), subsequent evaporation (8.41%), and pasteurization (8.41%). After heating, significant differentiation was also observed in the variation of both HMF (Hydroxymethylfurfural) content and diastase activity according to the botanical origin of the honey sample. In line with the biochemical analysis of honey, total phenolic decreased significantly during the pasteurization treatment. Evaporation was the most resistant thermal treatment due to its ability to maintain the level of HMF and the enzyme diastase as a standard for honey quality. However, changes made in physicochemical and biochemical quality are still in compliance with national and international legal limits.

Unique physicochemical properties and rare reducing sugar trehalulose mandate new international regulation for stingless bee honey

Stingless bee honey (SBH) of four stingless bee species (Heterotrigona itama, Geniotrigona thoracica, Tetragonula carbonaria, and Tetragonula hockingsi) from two geographic regions (Malaysia and Australia, n = 36) were studied for their physicochemical parameters, including total phenolic and multi-elemental contents. Sugar analysis confirmed the prominent presence of trehalulose in all samples. All SBH failed to meet the CODEX Standard for honey moisture, free acidity, and total fructose plus glucose levels. One-way ANOVA, principal component analysis (PCA) and hierarchical component analysis (HCA) confirm distinctive differences between Australian and Malaysian SBH with Australian SBH having significantly (P < 0.05) higher pH, total phenolic, total mineral, and electrical conductivity attributes. Toxic elements in all SBH were much lower than standard CODEX limit. The species G. thoracica produced honey with significantly (P < 0.05) higher trehalulose than both Australian bee species. This research will add value to SBH and hasten new international standards ensuring commercial viability, safety, quality, and marketability of SBH.

Botanical origin and characterization of monofloral honeys in Southwestern forest of Ethiopia.

The study was conducted to identify and characterize the monofloral honey types found in the Gesha‐Sayilem forest. A total of 15 honey samples were collected during the honey flow seasons. For honey pollen analysis, the method recommended by the International Commission for Bee Botany and harmonized methods of the International Honey commission were used. Data were analyzed using one‐way ANOVA, PCA, and Pearson correlation coefficients. Three monofloral honey types were identified, such as Schefflera abyssinica honey, Croton macrostachyus honey, and Vernonia amygdalina honey types. The mean moisture content of the honey samples of Vernonia amygdalina honey was 18.3 ± 1.02%, that for Schefflera abyssinica honey 18.1 ± 1%, and 21.2 ± 1.05% for Croton macrostachyus honey. The HMF value of the Vernonia honey ranged from 1.1 to 1.3 mg/kg, with a mean value of 1.2 ± 0.1 mg/kg; that of Schefflera abyssinica honey ranged from 2.2 to 2.5, with a mean value of HMF 2.3 ± 0.15; and that of Croton honey ranged from 2.4 to 2.6 mg/kg, mean value of 2.56 ± 0.15 mg/kg. There was a significant difference in the free acid content of honey samples due to the botanical origin of honey and sampling locations (p < .05). The electrical conductivity of honey samples in the Gesha‐Sayilem forest was found within an international range, with a maximum limit of 0.8 mS/cm for most nectar honey. There was a significant strong correlation between proline, free acid, and sucrose. Moisture content was positively correlated with electric conductivity, due to the dependable nature of electrical conductivity on honey moisture. The study area honey meets the basic honey quality standards both of the national and international honey quality specifications, except that the moisture content of croton honey which was some what out of the accepted range.

Use of the Composite Properties of a Microwave Resonator to Enhance the Sensitivity of a Honey Moisture Sensor.

A moisture sensor based on a composite resonator is used to measure different honey samples, which include imitation honey. The sensor changes its frequency response in accordance with the dielectric permittivity that it detects in the measured samples. Although reflectometry sensors have been used to measure the percentage of moisture in honey for almost a century, counterfeiters have achieved that their apocryphal product is capable of deceiving these kinds of sensors. Metamaterial features of the composite resonators are expected to improve their response when detecting lossy samples such as organic samples. It is also sought that these sensors manage to detect small differences not only in the real parts of the dielectric permitivities of samples but also in their imaginary parts, and, thus, the sensors are able to discern between real honey and slightly altered honey. Effectively, not only was it possible to improve the response of the sensors by using lossy samples but it was also possible to identify counterfeit honey.

Development of inclined plate honey moisture reduction system.

Honey is delicious, nutritious and has high medicinal value in comparison to other sweeteners. Honey is usually extracted from comb as immature product which results in high moisture which makes it more liable to be fermented by osmophilic yeasts. So, it needs to be processed for moisture reduction, to delay crystallization and to overcome the problem of fermentation. In the present investigation, a honey moisture reduction system was developed and tested to reduce the moisture content of honey to about 17%. The system consisted of a flat plate inclined at an angle. The plate was heated from the underside and honey for moisture reduction was re-circulated over it until desired moisture content was achieved. Experiments were conducted for honey moisture reduction at water temperature of 40-70°C with plate inclinations of 30°-60° according to four level full factorial design of experiment. The results showed that the total reduction time required for reaching moisture content of about 17% varied with water temperature and angle of inclination. The moisture reduction time required for reaching a moisture content of 17 percent at 40°C was about five times the time required at 70°C. The energy cost of honey moisture content reduction from 21.5 to 17% was Rs. 4.7 to Rs. 12.5 per kg.

Capped Honey Moisture Content from Four Honey Bee Species; Apis dorsata F., Apis florea F., Apis cerana F, and Apis mellifera L. (Hymenoptera: Apidae) in Northern Thailand

Honey moisture content from beneath capped honey storage cells was examined for four species of honey bees in northern Thailand. Three species, Apis dorsata, A. florea, and A. cerana are indigenous to SE Asia, the fourth species, A. mellifera, is a recently introduced species. It is assumed that capped honey will possess the lowest moisture content attainable under tropical conditions. Average honey moisture content was as follows: A. dorsata 22.7%, A. florea 20.1%, A. cerana 21.2% and A. mellifera 18.8%. Capped honey storage cells for the indigenous honey bee species frequently exceed the moisture content standard set by regulatory agencies for A. mellifera honey in Europe. The introduced, temperately adapted A. mellifera is capable of lowering honey moisture to regulatory standards even in the environmental restraints of high ambient temperature and relative humidity of northern Thailand.

Effect of ultrasonic energy density on moisture transfer during ultrasound enhanced vacuum drying of honey

The purpose of this work is to explore the water content, distribution and stage changes of honey during ultrasound enhanced vacuum drying process. Ultrasound enhanced vacuum drying of honey was carried out at ultrasonic energy density levels of 0, 0.4, 0.8, 1.2, 1.6 W/g, respectively, and the drying kinetics model was established. The transverse relaxation time T2 inversion spectra of honey at different ultrasonic energy densities during drying process were measured and the changing characteristics of internal moisture state were analyzed by using the low-field nuclear magnetic resonance (LF-NMR). The results showed that the process of honey during ultrasound enhanced vacuum drying could mainly be divided into two periods, namely accelerating rate period and falling rate period. The range of effective moisture diffusion coefficient (Deff) was from 0.7879 × 10−7 to 2.1850 × 10−7 m2/s and the Deff values increased with the rise of ultrasonic energy density. According to the nonlinear fitting based on 9 dynamic models, two-term exponential model was determined by the optimal model, and the values of R2, χ2 and RMSE were 0.9991, 0.001 and 0.0091, respectively. The LF-NMR results showed that immobilized water was the main moisture in honey, which was 96.47%. As the drying proceeded, the relaxation time of immobilized water (T22) and free water (T23) decreased, which indicated that their mobility reduced gradually. The relaxation time of bound water (T21) showed little changes. The amplitude of immobilized water (A22) and free water (A23) decreased significantly at the initial stage of drying, and the amplitude of bound water (A21) decreased significantly at the last stage. Magnetic resonance imaging results revealed that the moisture distribution in honey was uneven and the brightness of images started to darken with the increase of drying time. Therefore, the results of this work demonstrate that NMR is a promising method to measure and quantify residual water content, water distribution and state of water of honey in real time during the drying process.

Effect of Six Month Storage on Physicochemical Analysis and Antioxidant Activity of Several Types of Honey

Honey composition could change during storage, which might affect the quality of honey. Subsequently, it could reduce the honey commercial value. However, data on the effect of the storage on several types of local honey is still lacking. Thus, in this study, moisture content, pH and antioxidant level of honey stored at 4°C were analysed after six-month of the storage. Initially, physicochemical properties (moisture, electrical conductivity, ash content, pH, free acidity and hydroxymethylfurfural (HMF) level) and antioxidant levels of five local honey samples (Tualang, Gelam, Pineapple, Acacia and Kelulut honey) and Manuka honey as a control were determined. Afterwards, honey samples were stored at 4°C for six months and their moisture content, pH and antioxidant levels were monitored monthly. Physicochemical properties were measured based on the standard method set by the International Honey Commission (IHC). Antioxidant activity was determined based on previous studies. Most of the honey samples exhibited physicochemical properties within the range set by the Codex Standard for Honey but displayed lower antioxidant level compared to other studies. On average, honey moisture content increased by 0.1 to 0.4% while their antioxidant level increased by 2.6 mg GAE/kg to 6.3 mg GAE/kg monthly. In contrast, pH level of honey decreased by 0.03 to 0.09 monthly. Storage of honey at low temperature increases its moisture and antioxidant level while decreases its pH level. However, further study needs to be carried out to observe whether the pattern will continue even after a lengthy storage period exceeding six months.

Honey moisture reduction and its quality.

Beekeeping has been widely promoted in many countries as a major contributor to rural development. Honey is a sweet and viscous liquid which has sweetness due to the presence of monosaccharides. The major constituents of honey are sugars, water, proteins, enzymes, acids and minerals, while the major causes of quality deterioration include heating at high temperatures, high moisture content, adulteration, poor packaging and poor storage conditions. Heating not only eases the processing of bottling by reducing the viscosity of honey, but also reduces the water content in honey to prevent fermentation and delays the granulation by destroying large sugar nuclei. The paper discusses about the different honey moisture reduction systems designed by research workers as well as beekeepers at farm level and the different quality parameters affected by thermal treatment of honey.

Ling Heather Honey Authentication by Thixotropic Parameters

This paper assesses the actual reliability of four rheological parameters to help describe honeys that exhibit non-Newtonian behavior, being the most representative of which, ling heather (Calluna vulgaris (L.) Hull) honeys. Sampling included a representative number of unifloral ling heather honeys, non-unifloral honeys close to ling heather uniflorality, and other non-unifloral honeys containing ling heather. All experiments were performed at 25 °C and consisted on researching viscosity curves at different shear rates, as well as the time dependency of honey samples at a constant shear rate. Viscosity curves were correctly fitted by the Ostwald-de Waele model. Consistency coefficients (k) and flow behavior indexes (n) were calculated, and the Weltmann model was used to determine the stress decay behavior. The influence of honey moisture on k value was also researched. Hysteresis area and time-dependent thixotropic index B proved to be the most suitable parameters for a reliable ling heather honey authentication.

Conformational Redistribution of Honey Components following Different Storage Conditions

The present study aims at the investigation of the changes in water distribution among the organic components of selected honey samples following honey storage at different temperatures. Results, achieved by application of fast field cycling NMR relaxometry, revealed that the organic constituents were homogeneously distributed within the whole samples stored at room temperature. Conversely, after four months of refrigeration at 4°C, the organic systems were included in persistent clusters, as a consequence of the water release due to the larger stability of the intramolecular interactions over the intermolecular ones. The new conformational arrangements of the honey constituents entailed enhancement of honey moisture content. For this reason, it can be suggested that honey refrigeration prior to storage at room temperature may be detrimental for its long-term storage. In fact, higher risk of fermentation may occur once the sample is warmed after the first refrigeration step.

A small scale honey dehydrator.

A small scale honey dehydrator has been designed, developed, and tested to reduce moisture content of honey below 17%. Experiments have been conducted for honey dehydration by using drying air at ambient temperature, 30 and 40°C and water at 35, 40 and 45°C. In this dehydrator, hot water has been circulated in a water jacket around the honey container to heat honey. The heated honey has been pumped through a sieve to form honey streams through which drying air passes for moisture removal. The honey streams help in increasing the exposed surface area of honey in contact with drying air, thus resulting in faster dehydration of honey. The maximum drying rate per square meter area of honey exposed to drying air was found to be 197.0g/h-m(2) corresponding to the drying air and water temperature of 40 and 45°C respectively whereas it was found to be minimum (74.8g/h-m(2)) corresponding to the drying air at ambient temperature (8-17°C) and water at 35°C. The energy cost of honey moisture content reduction from 25.2 to 16.4% was Rs. 6.20 to Rs. 17.36 (US $ 0.10 to US $ 0.28 (One US $=62.00 Indian Rupee on February, 2014) per kilogram of honey.

Physicochemical properties of the Harenna forest honey, Bale, Ethiopia

In this study, the physicochemical properties of the Harenna forest honey were characterised. The Harenna forest honey moisture, reducing sugar, sucrose, water insoluble solids, ash, free acid, pH, HMF contents, electrical conductivity and specific rotation were found to be 17.89±1.02g/100g, 69.48±1.72g/100g, 2.43±1.02g/100g, 0.12±0.08g/100g, 0.19±0.09g/100g, 34.57±4.80meq/kg, 3.87±0.16, 0.84±0.46mg/1000g, 0.70±0.04mS/cm and −132±15.27 [α]D20, respectively. All quality indicators of honey from traditional and frame hives were within the criteria set by Codex Alimentarus (CA), European Union (EU) and Ethiopian standard, except for water insoluble solids. The type of hives significantly affected the moisture (p<0.01), reducing sugar (p<0.05), ash (p<0.05) and HMF (p<0.05) contents of the Harenna forest honey. The sampling location also significantly affected the moisture (p<0.001), water insoluble solids (p<0.01), ash (p<0.01), electrical conductivity (p<0.001) and specific rotation (p<0.001) values of the Harenna forest honey. Significant correlations were observed between moisture content and electrical conductivity (r=0.76, p<0.01), and electrical conductivity and specific rotation (r=0.74, p<0.01). Traditional hive has no negative effect on quality factors of honey if honey harvesting, handling and processing is properly carried out.

Karl Fischer Titration to determine moisture in honey: A new simplified approach

Honey, produced by Apis mellifera from nectar or honeydew, contains a discrete quantity of water (about 17%). The variability of water content influences the quality, the stability, the workability and the storage of honey. Moisture in honey is usually measured via determination of refractive index (RI); from the value measured, the percentage is calculated by an empirical formula or by “conversion” table. A possible alternative approach is the Karl Fischer Titration (KFT). The objective of this work was to find the optimal parameters for water determination in honey with KFT without any heat treatment of sample or working medium and the measurement of water content in more than 100 honeys of different botanical origin, using RI and KFT determinations. The water content, obtained with KFT, was usually higher than that determined by RI analysis. According to our results KFT seems to be the most reliable method.

Literature Review on Linear Regression Equations for Relating Water Activity to Moisture Content in Floral Honeys: Development of a Weighted Average Equation

A literature review on several existing linear regression equations for correlating water activity (a w) and refractometric moisture content in floral honeys was performed in order to provide a weighted average regression equation. For this purpose, a meta-analysis of the literature linear equations was made which takes into account the number of data points as well as the precision involved in the different literature studies. The weighted average linear regression equation is a general linear relationship to calculate the honey water activity on the basis of the honey moisture content. It was obtained from comparing and combining the results of ten independent studies involving 638 observations and including honeys from Argentina, Colombia, Spain, Germany, Czech Republic, China, Mexico, Cuba, Brazil, El Salvador, India, and Vietnam. It was also found that the proposed equation describes satisfactorily the water activity of concentrated (and supersaturated) glucose/fructose solutions, which would confirm that these sugars are the main determinants of water activity in honey.

On the nature of the relationship between water activity and % moisture in honey

Some theoretical basis of water activity in honey as well as the nature of its correlation with % moisture, are examined. For this purpose, the water activity of high concentrated glucose, fructose and glucose/fructose solutions (many of them supersaturated solutions) was determined and correlated with moisture content. It was found that the a w of glucose and fructose was identical for practical purposes. Literature data on the water activity and moisture content of a large number of honey samples (either fluid, crystalline or partially crystalline) from different geographical origin and botanical sources were statistically analyzed, and compared with the water activity of glucose/fructose solutions. A survey of literature data was performed to obtain and compare regression equations between water activity and % moisture for honeys from different sources.

The correlation between water activity and % moisture in honey: Fundamental aspects and application to Argentine honeys

The present work examined some fundamental aspects of the relationship between water activity and % moisture in honey. For this purpose a theoretical analysis was made on water activity lowering in sugar solutions and honey; the correlation between water activity and % moisture in Argentine honeys was then experimentally determined and explained on the basis of the above analysis. A very good straight line relationship (correlation coefficient 0.971) was found between both parameters in the range examined (15–21% moisture), and also the goodness of fit of the regression equation was found to be quite satisfactory. Previous literature results were compared with the present ones.

Response of Honey Bees, Apis mellifera L., to High-Voltage Transmission Lines 1

Honey bee colonies under a 765-kV power line (electric field [E-field[ 7 kV/m) showed effects, with hive height and weather-influenced hive current distribution the controlling factors. Hive current was a mean of 59 μA(= 1 m hive height) or 85 μA (1.5 m). Shielded controls under the line had E-fields and hive currents 150- to 300- fold and 100-fold lower, respectively, than exposed hives. Groups were exposed or shielded 8 or 16 weeks, with treatment reversal for some at week 8. A 16-week exposure did not affect percent honey moisture or teneral adult weight. When first exposed, colonies exhibited pronounced but transient elevations in temperature. Capped brood was normal in exposed 1-m hives but declined ( P <0.01) in 1.5-m hives by week 4, associated with higher incidence of queen loss and queen cells and colony failure. Weight gain was depressed in all exposed hives after 2 weeks, being severe in 1.5-m hives ( P <0.001 at week 5) and intermediate in 1-m hives (P = 0.05 at week 8). Effects were more pronounced the first 8 weeks than the last 8. Painted hive interiors reduced bio-effects, presumably by reducing internal current flow. Only exposed colonies propolized hive entrances, but amount and time of onset were not dose related. Treatment reversal at midseason resulted in reversal of colony behavior, manifested more with hive weight than brood. Overwinter survival of exposed groups was ≤29% compared with ≥71% among shielded ones.

Moisture in Honey: Review of Chemical and Physical Methods

Abstract A critical review is presented of the determination of moisture in honey by chemical (Karl Fischer) and several physical methods, including evaporation, distillation, refractometry, density, and viscosity. Methods are compared for precision and accuracy, and interrelationships are discussed. Wedmore’s interpretation of Chataway’s specific gravity results is shown to be based on a misconception.