## 3 Results and Discussion  
### Drying Kinetics  
The freeze-drying kinetics of foam-mat kiwiberry pulp are presented in Figure 1. The results show that the shelf temperature influenced the exhibited different patterns of water removal, and thus the drying curves. As expected, a shorter drying time was obtained for samples dried at the higher temperatures. The foam mat dried at 25 \({}^{\circ}\)C and 40 \({}^{\circ}\)C dried faster by 37.3 and 40.7%, respectively, compared to the sample dried at 10 \({}^{\circ}\)C (885 min). For instance, after 60 min of freeze drying, the MR outcomes ranged to 0.86 for the foam mat dried at 10 \({}^{\circ}\)C and 0.80-0.82 for the foam mats dried at 25 \({}^{\circ}\)C and 40 \({}^{\circ}\)C. Moreover, for the sample dried at 25 \({}^{\circ}\)C, the MR value was the lowest, which means that, in this case, the temperature of 40 \({}^{\circ}\)C did not cause an increase in the drying progress. This can be explained by the disruption of sublimation and dissolution of the material during the process. The results of this study are in accordance with those of other studies. In general, increasing the temperature of the drying air intensified the process course, which was found for foamed tomato puree dried at the layer of 15 mm in thickness via a vacuum and air-drying methods at temperatures of 50, 60 and 70 \({}^{\circ}\)C [27], foamed papaya pulp with different foaming agents (methyl cellulose, glycerol monostearate, egg albumin) using air-drying methods at temperatures of 60, 65 and 70 \({}^{\circ}\)C [38; 39], foamed mango pulp with different levels of egg albumin dried at temperatures of 65, 75 and 85 \({}^{\circ}\)C [40], foamed cocoa powder at the layer of 4 mm in thickness dried at temperatures of 50, 60 and 70 \({}^{\circ}\)C [11], foamed kiwiberry pulp dried at the layers of 4, 8 and 12 mm in thickness at temperatures of 50, 60 and 70 \({}^{\circ}\)C [15] and grapefruit puree freeze dried at room temperature and 40 \({}^{\circ}\)C [28]. The effective water diffusion coefficient was determined via the simplified [PERSON]'s second law and the relationship between the shelf temperature and the \(D_{\text{eff}}\) values is presented in Figure 1. The effective water diffusion coefficient of the freeze-dried samples varied from 2.47 \(\times\) 10\({}^{-9}\) to 4.51 \(\times\) 10\({}^{-9}\) m\({}^{2}\)/s. The higher values were noted for samples dried at a higher shelf temperature, and it was also found that the shelf temperature affected the \(D_{\text{eff}}\) values. This means that at a higher drying temperature, the water molecules can move faster, and thus provide a higher moisture diffusivity [41]. The \(D_{\text{eff}}\) parameter is a significant indicator of the optimization and evaluation of the drying processes and is primarily concentrated via the internal moisture movement, especially mass transfer mechanism and molecular and hydrodynamic diffusion [42]. For food, the value of this parameter should vary from 10\({}^{-11}\) to 10\({}^{-9}\) m\({}^{2}\)/s [7]. The obtained results are in good accordance with the data presented in the literature, which show the tendency to increase the \(D_{\text{eff}}\) values with increased drying temperature. For instance, this tendency was noted by [PERSON] et al. [40], who dried foam-mat mango pulp with 3% egg white using a convective drying method at three different temperatures (65, 75 and 85 \({}^{\circ}\)C). It was stated that an increase in temperature resulted in an increase in \(D_{\text{eff}}\) values, which were 1.68 \(\times\) 10\({}^{-8}\) m\({}^{2}\)/s and 2.48 \(\times\) 10\({}^{-8}\) m\({}^{2}\)/s for 65 and 85 \({}^{\circ}\)C, respectively. [PERSON] et al. [15] stated the same tendency in \(D_{\text{eff}}\) values after the convective drying of foam-mat kiwiberry pulp with 2% ovalbumin.