# Shaping the Properties of Osmo-Dehydrated Strawberries in Fruit Juice Concentrates
## 3 Results and Discussion
### The Impact of Fruit Concentrates on the Physical Properties  
2.1 The Impact of Fruit Concentrates on the Dry Matter Content, Water Activity, and Color of Osmotically Dehydrated Strawberries  
The dry matter content in fresh strawberries was 8.2 \(\pm\) 0.05% and, as a result of osmotic dehydration for 0.5 h, it increased twice. After 3 h of osmotic dehydration, it increased to 31.3-36.5%, depending on the type of osmotic agent (Figure 2). Thus, after 3 h of the osmotic dehydration process, the water content was in the range of 63.5-68.7%. A similar effect was observed in sour cherry subjected to osmotic dehydration in concentrated apple juice and a mixture of apple and sour cherry juices [15]. The highest values were found in strawberries dehydrated in cherry juice concentrate. Compared with traditional sucrose, the use of juice concentrates increased the dehydration effect of strawberries by 10-46%, omitting the dry matter of fruits dehydrated for 3 h in chokeberry and strawberry juice concentrates, with values similar to those obtained in the sucrose solution. A longer dehydration time increased the content of dry matter, regardless of the type of osmotic agent, as a result of the mass transfer [34]. Figure 1: Effect of the type of osmotic agent (fruit concentrates) on the mass exchange kinetics of osmodehydrated strawberries: (**a**) weight reduction, (**b**) water loss (dashed lines), and solid gain (regular lines). Water activity is a parameter related to moisture content [7]. The water activity of fresh strawberries was 0.954 \(\pm\) 0.08. Irrespective of the used osmotic substance, it decreased along with the longer dehydration time (Figure 2). Statistical analysis showed that the time of the osmotic dehydration has a significant effect on this parameter (_p_ < 0.05). Significant differences in the water activity of osmotically dehydrated strawberries were observed between the initial (0.5 h) and the final time of osmotic dehydration (3 h). However, there was no significant effect of the osmotic agent on the level of water activity in dehydrated strawberries (_p_ > 0.05). The highest decrease in water activity to 0.873 was obtained in strawberries dehydrated in a cherry concentrate after 3 h of dehydration. The water activity of strawberries at this level protects them against the development of pathogenic microorganisms but does not ensure full microbiological stability. According to [PERSON] et al. [35], a slight decrease in high water activity causes a significant reduction in the relative rate of all growth reactions and microbial destruction. However, further processing is required to assure the longer stability of the product, e.g., drying [36; 37]. The color of food is one of the factors that determine the choice and willingness to consume a product. As it has been shown in many publications, during various treatments, transport, and storage, the color changes [23; 38], therefore the selection of an osmotic agent is of particular importance in shaping the properties of osmotically dehydrated fruits. Fresh strawberries at the stage of consumption maturity were characterized by L*, a*, and b* color parameters at the levels of 33.8 \(\pm\) 3.9, 24.1 \(\pm\) 3.8, and 19.7 \(\pm\) 4.5, respectively (Table 2).