# Evaluating the Physicochemical Properties of Some Kosovo's and Imported Honey Samples
## 1 Introduction  
Honey produced by bees is a very concentrated natural sugar solution, which consists of a complex mixture of carbohydrates and is consumed as a food with high nutritional value [1]. It is produced worldwide and is known as the only product in the form of concentrated sugar with a low content of enzymes (glucose oxidase, catalase, phosphatase), glucose and sucrose (65--the total amount of soluble matter), proteins, amino acids, organic acids, vitamins, lipids, volatile chemicals, flavonoids, phenolic acids, and various minerals [2; 3; 4]. The biochemical characteristics of honey and its quality depend on the climatic conditions, mode of production, maturity, storage conditions, and source of honey nectar [5; 6; 7; 8]. The identity and quality requirements of honey are regulated by the Codex Alimentarius standard [9] and the EU Honey Directive [10], which are indicated in Table 1.  
Different researchers have investigated the physicochemical properties of honey from many countries worldwide [11; 12; 13; 14]. The moisture content is important as it influences many other parameters in honey, such as the sugar content, hydroxymethylfurfural (HMF), viscosity, crystallization, as well as sensory and microbial properties. Codex Standard for Honey of 2001 [9] stipulates that the moisture content in honey should not exceed 20 g100 g\({}^{-1}\). Authors have also mentioned that honey, being hygroscopic, can absorb moisture, thus the moisture in honey can increase depending on the processing operations, as well as due to inadequate storage conditions [11; 12]. The natural acidity and low pH level of honey are also important parameters since they contribute to inhibition of microbiological growth, but on the other hand, these two parameters could also be related to adulteration and deterioration of honey. The Codex Alimetarius [9] permits a maximum value of 50.0 meq kg\({}^{-1}\) free acidity and higher values may indicate possible fermentation of sugars into acids. The soluble solid content is a parameter that shows the presence of most sugars in honey. The honey product is considered qualitative when values are above 80 \"Brix [15]. Electrical conductivity and ash are used as indicators of honey quality and depend on the mineral content of the honey. Ash presents as an inorganic residue after carbonization, while electric conductivity measures all ionizable organic and inorganic substances [16]. The EU Honey Directive stipulates a maximum permitted value of 0.8 uS cm\({}^{-1}\) conductivity for nectar honey except for chestnut honey, which should not be less than 0.8 uS cm\({}^{-1}\)[10]. Apart from other factors, the quality of honey can also be affected by the use of excessive heating either during the production process or due to improper storage conditions [17]. The HMF (hydroxymethylfurfural) content is considered an important parameter for the measurement of honey quality and authenticity. It is usually absent or only low amounts occur naturally in fresh honey, while high levels may be a result of inadequate storage, adulteration with sugar additives, or application of heat to decrease honey's viscosity [18]. Since high levels of HMF may be the result of excessive heat treatment, improper storage, or possible addition with other sugars or syrups, food standards regulate the levels of HMF in honey. The Codex Alimetarius Commission recommends the maximum amount of HMF to be 40 or 80 mg/kg for honey from tropical climates [9; 19]. The European Union established the same maximum amount of HMF [20]. The Republic of Kosovo has a tradition in honey production. Data on beekeping, although scarce, show that the number of beehives and total production sharply increased in Kosovo after the war. The total honey produced in Kosovo in 2019 was around 2198 tons [21].