The second important indicator in the quality assessment
was the water activity, which affects many factors determining
the product stability, e.g. the development of microflora. Basically, a microbiologically safe biomaterial is characterized by the
water activity less than 0.6, however, this value does not exclude
enzymatic browning. The Maillard reactions appear unfortunately
mostly in the water activity ranged from 0.5 to 0.8. Nevertheless,
a reduction in aw value due to drying, minimizes the loss of food
quality caused by microbial activity [14,30]. Water activity of cherry
samples was measured before and after drying (3 h from the end
of the process). For this purpose a few cherries were grinded in a
mortar, then were placed in the converter chamber until the equilibrium was reached. The measurements of aw changes are shown
in Fig. 5.