## 3 Results and Discussion  
The results of the conducted experiments (in three repetitions) are presented in Figure 1. The figure demonstrates mass changes and the rate of mass changes (Figure 1a), dry matter changes and the rate of dry matter changes (Figure 1b), water changes and the rate of water changes (Figure 1c), moisture content changes and the rate of moisture content changes (Figure 1d), and volume changes and the rate of volume changes (Figure 1e) during the course of dried red beets cubes' rehydration. The mass, dry matter mass, water mass, moisture content, and volume of rehydrated dried red beets for 10, 20, 40, 90, 180, and 360 min of the rehydration depended (in a statistically significant way) on the solid-to-liquid ratio. It can be seen (Figure 1a) that at all investigated values of the solid-to-liquid ratio, water uptake increased whereas the rate of water uptake decreased with increasing rehydration time. The higher rehydration rate at the beginning of the process could be caused by fast filling the capillaries of the dried red beets near the surface with the rehydration water [26]. When the rehydrated samples approached the saturation level, the discussed rate was close to zero, so it can be accepted that the mass of the rehydrated material attained the state of equilibrium. Such a typical rehydration behaviour has been observed for kiwifruits [27], lablab bean seeds [28], potatoes [29], wheat starch, wheat protein concentrate, and whey protein isolate [30]. As far as the influence of the solid-to-liquid ratio on the course of mass gain was concerned, it can be stated that at the beginning of the process, the rehydration rates at all considered solid-to-liquid ratios could be treated as almost the same. Then, samples rehydrated in a smaller amount of water reached the state of equilibrium more quickly than samples rehydrated in a larger amount of water. The value of equilibrium sample mass increased with the increasing solid-to-liquid ratio. Similar results obtained by [PERSON] [31] concerned rehydration of dried parsley slices at the solid-to-liquid ratios of 1:10, 1:20, 1:30, 1:40, and 1:50. At all investigated values of the solid-to-liquid ratio (Figure 1b), the rate of dry matter loss was faster in the initial period of rehydration and then slowed down. The discussed rate was faster at the beginning of the process, because the solid concentration gradient between rehydrated dried red beet cubes and rehydrating water was high. As the solid concentration in rehydrated samples equilibrated with a rehydrating medium, the rate of dry matter loss was gradually reduced [30]. A similar course of rehydration has been reported for apples [32], carrots [33; 34], and parsley [31]. It can be stated that in the initial period of rehydration, the rates of dry matter loss at all investigated solid-to-liquid ratios were almost the same. In the further stage, dried red beet cubes rehydrated in a smaller amount of water attained a lower loss of dry matter. It could be explained in such a way that in case of a smaller water amount, solid concentration in the rehydrating medium grew quickly and both concentrations (in the rehydrated sample and rehydrating water) approached the equilibrium state faster than in a larger water amount. It can be however noticed that the equilibrium concentrations of dry matter in samples rehydrated in water in case of the solid-to-liquid ratios of 1:20, 1:15, and 1:10 were close to each other. Similar dependences were noticed by [PERSON] [31] for the rehydration of dried apple slices. Figure 1: Mass changes and rate of mass changes (**a**), dry matter changes and rate of dry matter changes (**b**), water changes and rate of water changes (**c**), moisture changes and rate of moisture content changes (**d**), and volume changes and rate of volume changes (**e**) for the rehydration (distiller water; 20 \({}^{\circ}\)C) of dried red beets cubes at different solid-to-liquid ratios of 1:20 (), 1:15 (), 1:10 (), 1:5, (), 1:5, (), 1:3 (), and 1:1 ().