# Quality Assessment of Honey Powders Obtained by High- and Low-Temperature Spray Drying
## 1 Introduction  
Honey is a natural raw material produced by _Apis mellifera_ bees from collected flower nectar or secretions of living parts of plants or excrete of insects sucking the juices of living parts of plants (honeydew). It has not only the aroma characteristics but can improve the human health. Honey is not a medicine but, as food, can have a supportive application in the prevention of diseases [1]. There are many types of honey, their chemical composition is significantly different, as well as the taste and smell. Honeydew honey contains many more minerals, polysaccharides, and dextrins than nectar honey. It is also rich in resins and essential oils and is used against diseases of the upper respiratory tract, asthma, pneumonia, and tuberculosis. Different types of honey have different susceptibility for crystallization, depending on the sugar profile. Rape honey contains a higher content of glucose as compared to fructose, crystallizes very quickly, and obtains a consistency of hard and white color [2, 3].  
Honey is added to cakes, biscuits, dietary supplements, and it goes well with milk-based products such as yogurts [4]. However, the use of honey on an industrial scale is limited due to its high viscosity, causing sticking of devices and handling problems [5, 6]. On the contrary, the powdered form is more convenient, offering many advantages, including easy storage, transport, dosing, and combining with other powder products [7, 8, 9].  
Spray drying is still the technique most commonly used to obtain a powder forms of food. The advantages of spray drying are relatively low cost, good availability of equipment, and suitability for sensitive products with high potential of producing powders characterized by high quality [10; 11]. However, during traditional spray drying high temperature (usually above 180 \({}^{\circ}\)C) is applied. In principle, the decrease in drying temperature allows the preservation of bioactive compounds and sensory characteristics of dried materials. Decreasing the inlet temperature of spray drying below 100 \({}^{\circ}\)C, an innovation, which was described recently by [PERSON] et al., 2019, [PERSON] et al., 2019, has not been achieved by other researchers before [12; 13; 14]. Drying is the simultaneous exchange in heat and mass. However, the resistance of mass movement far exceeds the resistance of heat movement. At the same time, the driving force of the process is the difference between the water vapor pressure of the dried material and the vapor pressure of the drying air. Thus, by reducing the humidity of the air, it is possible to evaporate water from the drying material at a lower temperature [14].  
FTIR spectroscopy is currently gaining popularity in the context of analyzing food products concerning their potential health benefits. Its value stems from the speed, non-invasiveness, and, above all, reliability of the results.  
The aim of the paper was to compare the quality of rapeseed and honeybee honey powders, after spray drying by two approaches--traditional high temperature spray drying (inlet air 180 \({}^{\circ}\)C) and innovative low-temperature spray drying with the use of dehumidified air as a drying medium (inlet air 75 \({}^{\circ}\)C). It was assumed that both the type of honey and the drying temperature could influence the bioactive (polyphenol content and antioxidant activity) and sensory properties (content and types of aromatic compounds) of the obtained powders.