The Influence of Thermal Treatment and Spray Drying on the Physicochemical Properties of Polish Honeys

The effect of heat treatment (50, 70 and 90C) and spray drying, with the addition of Arabic gum (inlet air temperature: 180C; outlet air temperature: 70C), on the diastase activity and hydroxymethylfurfural (HMF) content in multifloral honey (MFH) and rape honey (RH) was investigated. The physical properties of the powders were studied, including particle shape and size distribution, water content, bulk loose and tapped density, and hygroscopicity. During heat treatment, diastase activity was a more sensitive parameter than HMF content: its values decreased below admissible level (8 DN Schade units) for samples treated at 70 and 90C, while HMF increase exceeded admissible upper limit (40 mg/kg). Powders were characterized by low water content and good or medium flowability. Diastase activity in the powders remained at the same level as in fresh honeys, while HMF content increased by 1.8 (MFH) and 26.1 times (RH), exceeding maximum admissible value in the case of RH. PRACTICAL APPLICATIONS: Hydroxymethylfurfural (HMF) content and diastase activity are two major parameters used as honey quality indicators. This work shows the effect of heat treatment on the values of these two parameters in two types of honey. The results indicate that honey diastase activity decreases with temperature increase, while HMF increases, in the 50–90C range, and this behavior is different in multifloral honey than in rape honey, directly influencing honey processing and handling. Moreover, the paper deals with a difficult problem: honey production in a powder form, showing that it is possible to obtain powdered honey of good physical properties by spray drying with the addition of Arabic gum as a carrier material. The results show also that diastatic activity during spray drying was preserved, which is important for the final quality of the product.