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The main objective of this work was to determine the significant physicochemical and bioactive parameters of honeys originating from Iraqi Kurdistan. For this purpose, honey samples (n = 16) were taken directly from Kurdish beekeepers from different places of Dohuk and Erbil Governorate in 2018 and 2022. The following parameters were analyzed: moisture content, electrical conductivity, diastase activity, hydroxymethylfurfural content, pH, free acidity, content of saccharides, total phenolic content, total flavonoid content, color, color intensity and DPPH, FRAP. Another objective of this work was to compare the properties of Kurdistan honeys with the requirements of European Union law and with the honeys of Central Europe. A total of 48 honey samples were included in the comparison. It was detected that the honeys produced in Iraqi Kurdistan met the strict quality criteria set by European law, which is important information for local beekeepers and experts in relation to honey production and an opportunity to set local limits of honey quality. Despite the different climatic and topographical conditions, the available flora, and the different species of bees, the properties of Iraqi Kurdistan honeys were similar to the properties of honeys from the Czech and Slovak Republics. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the effect of freeze-drying and vacuum-drying on moisture, water activities (aw), total soluble solid (TSS), hydroxymethylfurfural (HMF), diastase activity, total phenolic content (TPCs), and antioxidant activities (ABTS, DPPH, FRAP, ORAC) of longan (Dimocarpus longan Lour.) blossom honey and Siam weed (Chromolaena odorata Lour.) honey. The fresh longan blossom honey and Siam weed honey were collected from a local apiarist in Northern Thailand. Freeze-drying at 0.013 kPa, −54℃ for 72 h or vacuum-drying at 2.5 kPa at 60 ℃ for 12 h was applied to dehydrate fresh honey. The moisture of freeze-dried samples was 10.10% for longan blossom honey and 11.50% for Siam weed honey, and the aw of both freeze-dried honeys was 0.43. Freeze- and vacuum-dried produced more TSS than fresh honey did (p ≤ 0.05). However, the amounts of TSS derived freeze-dry and vacuum-dry were not significantly different. Freeze-dried honey contained the highest HMF and the lowest diastase activity regardless of honey origins (p ≤ 0.05). Drying processes significantly increased the TPCs levels of honey (approximately 2 folds by freeze-drying method). The antioxidant activity of dried honey was significantly higher than that of fresh honey. It was observed that the freeze-drying method tended to better preserve the antioxidant activity of honey compared to vacuum-drying methods in both types of honey. The results indicated that drying processes significantly affect the quality of dried honey, including TSS, HMF, diastase activity, TPCs, and antioxidant activity. In this study, freeze-drying emerged as the relatively low temperature drying method that can preserve the quality of honey, especially in terms of TPCs and antioxidant activity.

The thermal treatment of honey is used to prevent honey crystallization which is one of the main problems that face beekeepers. In this study three samples of honey were heated at 40, 60, 80 and 100 °C, as a function of time in hours (h). Heating the samples at 40 °C did not show any significant effect on hydroxymethylfurfural (HMF) production or diastase enzyme activity up to 95 hours. Heating to higher temperatures 60, 80 and 100 °C resulted in a regular increase in HMF content and drop-off in diastase activity as a function of time. The HMF content reached 40 mg/kg after 80, 12.5 and 6 hours. For the three samples at 60, 80 and 100 °C respectively. Conversely, diastase enzyme activity reached close to 8 IU after 96, 12.5 and 5 hours. For the following temperatures 60, 80 and 100 °C respectively. The results showed that heating temperatures up to 40 °C is safe for long-term storage, while heating at 60 °C could be used but for a shorter treatment time. Results showed that the must temperature does not exceed 60 °C for 5 hours or 80 °C for one hour to preserve the honey's quality. The reaction rate constants and activation energy Ea of HMF formation in three samples were found 83.07, 91.79 and 89.57 kJ.mol-1 respectively. Therefore, honey can be preserved in this way, while at the same time the HMF remains below the permissible values, and the enzymatic activity remains at its highest level.

The main objective of this work was to determine the significant physicochemical and bioactive parameters of honeys originating from Iraqi Kurdistan. For this purpose, honey samples (n = 16) were taken directly from Kurdish beekeepers from different places of Dohuk and Erbil Governorate in 2018 and 2022. The following parameters were analyzed: moisture content, electrical conductivity, diastase activity, hydroxymethylfurfural content, pH, free acidity, content of saccharides, total phenolic content, total flavonoid content, color, color intensity and DPPH, FRAP. Another objective of this work was to compare the properties of Kurdistan honeys with the requirements of European Union law and with the honeys of Central Europe. A total of 48 honey samples were included in the comparison. It was detected that the honeys produced in Iraqi Kurdistan met the strict quality criteria set by European law, which is important information for local beekeepers and experts in relation to honey production and an opportunity to set local limits of honey quality. Despite the different climatic and topographical conditions, the available flora, and the different species of bees, the properties of Iraqi Kurdistan honeys were similar to the properties of honeys from the Czech and Slovak Republics.

The thermal treatment of honey is used to prevent honey crystallization which is one of the main problems that face beekeepers. In this study three samples of honey were heated at 40, 60, 80 and 100 °C, as a function of time in hours (h). Heating the samples at 40 °C did not show any significant effect on hydroxymethylfurfural (HMF) production or diastase enzyme activity up to 95 hours. Heating to higher temperatures 60, 80 and 100 °C resulted in a regular increase in HMF content and drop-off in diastase activity as a function of time. The HMF content reached 40 mg/kg after 80, 12.5 and 6 hours. For the three samples at 60, 80 and 100 °C respectively. Conversely, diastase enzyme activity reached close to 8 IU after 96, 12.5 and 5 hours. For the following temperatures 60, 80 and 100 °C respectively. The results showed that heating temperatures up to 40 °C is safe for long-term storage, while heating at 60 °C could be used but for a shorter treatment time. Results showed that the must temperature does not exceed 60 °C for 5 hours or 80 °C for one hour to preserve the honey's quality. The reaction rate constants and activation energy Ea of HMF formation in three samples were found 83.07, 91.79 and 89.57 kJ.mol-1 respectively. Therefore, honey can be preserved in this way, while at the same time the HMF remains below the permissible values, and the enzymatic activity remains at its highest level. [ABSTRACT FROM AUTHOR]

The honey quality can vary based on various factors such as plant origin, geographical area, production method and storage. By determining the quality characteristics of honey, it is possible to ensure the quality level as well as the existence of fraud in it. In this study, some physico-chemical, rheological and microbiological characteristics of 14 types of honey of Sistan and Baluchestan and Qazvin provinces (six natural honey samples and one counterfeit honey sample from each province) were investigated. The results indicated that there was no significant difference between amounts of reducing sugar of natural honey samples. The highest significant sucrose value belonged to the counterfeit samples and Diyalabad Qazvin and Ziziphus honey of Chabahar had the lowest values. Moisture content of samples varied from 12.5 to 17.21%. Diastasis activity of counterfeit samples was zero and Astragalus-Thymus of Tarom Qazvin with 08.09 DN had the lowest diastase activity among the natural honey samples. HMFcontent of natural samples was in the range of 3.9 to 7.80 mg/kg whereas for Zabol and Qazvin counterfeit honey was measured 341 and 280 mg/kg respectively. The highest and lowest fructose to glucose ratio was obtained for the samples of Ziziphus of Chabahar (1.22) and Alhagi honey of Zabol (0.69). In general, Sistan and Baluchestan samples had the higher viscosity compared to Qazvin provine’s ones. Furthermore, the highest contamination of osmophilic yeasts and mold belonged to counterfeit honeys. According to the results of this study, the quality of honey can vary significantly depending on the geographical location and plant origin. Also, some quality indicators of honey, especially the amount of sucrose, diastase activity and hydroxymethylfurfural content can be used as useful tools to detect the adulteration of the product. [ABSTRACT FROM AUTHOR]

In this study, three parameters (hydroxymethylfurfural, diastase activity and invertase activity) were used to evaluate the quality of twenty samples of multifloral honey from northern Algeria heated by a traditional method (conventional heating in a water bath at 100 °C) for five treatment periods (2, 4, 6, 8 and 16 min). The assay was carried out with honey samples whose initial HMF, diastase activity and invertase activity values were within the recommended food authority limit. HMF was determined by HPLC, diastase was measured with Phadebas and invertase was determined using the Siegenthler method. During heating, it was observed an increase in the HMF related to an increase in temperature, but still below the international standard limit (40 mg.kg-1 ). Diastase activity and invertase activity also decreases during heating. However, invertase is more heat-sensitive and heating time than diastase and HMF, and it's an important parameter to determine if honey has been submitted to heating. Therefore to liquefy honey we can use this method but with a low temperature and a short time because time has a deep impact on the quality of heating treatment of honey. [ABSTRACT FROM AUTHOR]

The present study was done to optimize the power ultrasound processing for maximizing diastase activity of and minimizing hydroxymethylfurfural (HMF) content in honey using response surface methodology. Experimental design with treatment time (1-15 min), amplitude (20-100 %) and volume (40-80 mL) as independent variables under controlled temperature conditions was studied and it was concluded that treatment time of 8 min, amplitude of 60 % and volume of 60 mL give optimal diastase activity and HMF content, i.e. 32.07 Schade units and 30.14 mg/kg, respectively. Further thermal profile analyses were done with initial heating temperatures of 65, 75, 85 and 95°C until temperature of honey reached up to 65°C followed by holding time of 25 min at 65°C, and the results were compared with thermal profile of honey treated with optimized power ultrasound. The quality characteristics like moisture, pH, diastase activity, HMF content, colour parameters and total colour difference were least affected by optimized power ultrasound treatment. Microbiological analysis also showed lower counts of aerobic mesophilic bacteria and in ultrasonically treated honey than in thermally processed honey samples complete destruction of coliforms, yeasts and moulds. Thus, it was concluded that power ultrasound under suggested operating conditions is an alternative nonthermal processing technique for honey. [ABSTRACT FROM AUTHOR]

The physicochemical properties, colour characteristics and dynamic viscosity of fresh rapeseed honey (control, CON) and those stored for 18 months at room temperature (RT) or in freezer (FRO) were compared. The significant decrease of pH after storage was found. Honey stored at RT showed an increase of 5-hydroxymethylfurfural (HMF) (+543.0 %) and decrease of diastase activity (−24.4 %), while in FRO samples the decreasing course (−50.5 and −7.3 %, p > 0.05) were found in comparison with CON samples (3.07 and 28.37 mg kg). The negative correlation between HMF content and diastase activity was found. The temperature of storage significantly influenced colour parameters, however, RT differentiated colour of honey to a greater extent (ΔE = 20.37) than FRO (ΔE = 8.07). The lightness (L*), hue (h°), whiteness index (WI) and colour intensity (ABS) of CON honey samples were similar to honey from FRO. The dynamic viscosity was significantly higher in honey stored in FRO in comparison to CON honey and honey stored at RT. However, in comparison with CON honey, higher (almost twice) viscosity for honey stored at RT was observed. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize and classify 10 honey samples collected from different regions of Iran based on their physicochemical properties. Moisture, ash and hydroxymethylfurfural content, pH, electrical conductivity, diastase activity, color, and fructose to glucose ratio were determined. Phenolic and flavonoid compounds, antioxidant activity, and the ability to inhibit enzymatic browning were also evaluated in the samples. Based on diastase activity and hydroxymethylfurfural content, Tamarisk honey showed the best quality. The highest ratio of fructose to glucose (1.5) belonged to Ziziphus. Coriander honey with the lowestL* (18.9) was considered darker than other samples. High correlation coefficients between phenolic, flavonoid compounds, and antioxidant activity indicated that these compounds are mainly responsible for the antioxidant capacity of honey. Based on the first principal component, honey samples were classified into four main groups. The first group included coriander and ziziphus, the second group was dill, the third group contained thyme, parsley, and qanqal, and the fourth group included astragal, alfalfa, tamarisk, and orange blossom. [ABSTRACT FROM PUBLISHER]

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The effect of heating at various temperatures (30, 40, 50, 60, 70 and 80 °C) on dynamic viscosity, colour, 5-hydroxymethylfurfural (5-HMF) concentration and diastase activity of raw rape honey were assessed. In fresh honey, moisture, ash, free acidity, pH and electrical conductivity averaged 185.3 g kg, 1.2 g kg, 18.71 mEq kg, 4.2 and 0.25 mS cm, respectively. Heating significantly ( p ≤ 0.05) increased lightness (L*), yellowness (b*), chroma (C*), hue (h°) values, but decreased redness (a*). The viscosity at 20 °C (33.6 Pa s) differed significantly ( p ≤ 0.01) with those at 30, 40 and 50 °C (8.2, 2.5, and 1.6 Pa s, respectively). Diastase activity decreased concomitant with heating at higher temperatures. Honey heated at 80 °C for 15 min showed the maximum increase of 5-HMF content, with an average of 1.9 mg kg (62 %), compared to unheated samples. Heating for 15 min between 50 °C and 80 °C did not significantly degrade the quality of the honey, but, slightly enhanced formation of 5-HMF and reduced the diastase activity. [ABSTRACT FROM AUTHOR]