Water activity and colour parameters changes during storage of linden and buckwheat honeys

The aim of the study was to evaluate selected quality parameters of honey: water activity and colour parameters and their changes during storage under different conditions. Also the effect of the botanical origin of honey and filtration process on these parameters were examined. In both types of honey, filtered and unfiltered, the initial water content was determined by refractometry, initial water activity was determined by the AquaLab and colour parameters L* a* b* were measured using a colorimeter Chroma Meter CR 400. In addition, a measurement of water activity of the tested honeys stored for 90 days under a constant relative humidity in the range of 0,069-0,932 water activity was done. Analysis of the examined water activity of the honey stored for 90 days showed that storage under conditions of low relative humidity (aw = 0,069-0,548) decreased water activity of honey in relation to their initial water activity, while storage under conditions of high relative humidity (aw>0,548) caused an increase in water activity of honey. It has been also shown that filtration affects the water activity. Storage in different relative humidity conditions and filtration have an impact on the values of the colour parameters of honey, too.