# The Effect of Hybrid Drying Methods on the Quality of Dried Carrot
## 3 Results
The average values of shrinkage are presented in Figure 5. It was shown that the applied drying methods affected the material shrinkage. The highest value of shrinkage is characteristic of convection-dried carrots (K), for which this parameter is 68.95%. The dried material obtained by the methods of combined drying with the use of freeze-drying (F-K, F-M, K-F) was characterized by shrinkage with lower values not significantly different from each other (Table 5). The results ranged from 54.75-58.16%. The lowest shrinkage is characteristic for carrots subjected to combined drying (F-K) 54.75%. Between the results \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample** & **Count** & **Average** & **Standard Deviation** & **Coeff. of Variation** \\ \hline K-F & 3 & 94.1167 & 0.862863 & 0.916802\% \\ K & 3 & 94.1 & 1.30288 & 1.38457\% \\ F-M & 3 & 96.4667 & 0.297714 & 0.308618\% \\ F & 3 & 98.36 & 0.31 & 0.315169\% \\ F-K & 3 & 95.68 & 1.07791 & 1.12658\% \\ M-F & 3 & 94.4633 & 0.749689 & 0.793629\% \\ M & 3 & 95.3667 & 0.520416 & 0.545701\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The results of the analysis of the variance of dry matter content for dried carrots depend on the drying method. Statistical significant differences at \(p<0.05\). Designations in Table 1.  
Figure 3: The impact of the type of drying method on the dry matter content of dried carrots. The same letters (a–c) in individual columns indicate the absence of a statistically significant difference between the samples (significance level 0.05). Designations in Table 1.  
The effect of the drying method on the porosity of dried carrots was shown in Figure 6. The highest porosity value of 84.14% was obtained in freeze-dried carrots (F). The convective dried sample (K) was characterized by the lowest porosity among all drying methods. The combination of freeze-drying and convection-drying (F-K, K-F) allowed us to obtain statistically significant lower porosity of 44.28%, 36.7%, compared to freeze-dried (F) samples but higher than convective dried (K) (Table 6). Differences were statistically significant. The dried material obtained by hybrid (combined) methods with the use of microwaves and freeze-drying (M-F, F-M) had a porosity of 57.16 and 52.06%, respectively, and results were significantly higher than for the microwave-dried (M) 37.38%. The internal structure of dried carrots was examined using a scanning electron microscope (Figure 7). The convection-dried carrot tissue (K) (Figure 7A) is characterized by a regular distribution of pores, evenly shaped and of similar sizes, in high-density clusters. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample** & **Count** & **Average** & **Standard Deviation** & **Coeff. of Variation** \\ \hline K-F & 3 & 36.7233 & 0.546474 & 1.48808\% \\ K & 3 & 31.82 & 0.230651 & 0.724863\% \\ F-M & 3 & 57.1533 & 0.381095 & 0.666794\% \\ F & 3 & 84.1433 & 0.388115 & 0.461255\% \\ F-K & 3 & 44.71 & 0.39281 & 0.878574\% \\ M-F & 3 & 52.0233 & 0.120554 & 0.231731\% \\ M & 3 & 37.46 & 0.383145 & 1.02281\% \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The results of the analysis of the variance of porosity for dried carrots depend on the drying method. Statistical significant differences at \(p<0.05\). Designations in Table 1.  
Figure 6: The impact of the type of drying method on the porosity of dried carrots. The same letters (a–g) in individual columns indicate the absence of a statistically significant difference between the samples (significance level 0.05). Designations in Table 1.  
The freeze-dried material (F) (Figure 7C) in the microscopic image is distinguished by a large number of pores of small diameter, creating a delicate porous structure. Compared to the convection (K) (Figure 7A) and microwave (M) (Figure 7F) methods, the structure of the tissue was not exposed to high temperature, the pores are much smaller and there are no numerous damages and structural cracks.