## 3 Results and Discussion
### Further Experimental Validation
#### 3.2.2 Quality Assessment
Initially, the fresh strawberries had a firmness of 2.41 \(\pm\) 0.58 N. With increasing immersion time, there was a general trend of decreasing firmness, although this decrease was not significant in most cases. Specifically, the firmness values at 170 min (2.34 \(\pm\) 0.72 N) and 190 min (1.78 \(\pm\) 0.10 N) showed a reduction compared to the initial firmness, but these changes were not statistically significant (\(p\geq\) 0.05). At 220 min, firmness slightly increased to 2.03 \(\pm\) 0.18 N, indicating a temporary stabilization of the fruit's structural integrity during this phase of dehydration. Beyond 220 min, the firmness of the strawberries continued to decline, reaching 1.43 \(\pm\) 0.20 N at 270 min and further decreasing to 1.05 \(\pm\) 0.16 N at 300 min. The changes in firmness at these longer immersion times were statistically significant to the initial firmness of the slices. This suggests that the structural integrity of the strawberries was relatively well maintained throughout most of the osmotic dehydration process, with significant changes only observed at extended immersion times. The observed decrease in firmness found during osmotic dehydration aligns with findings from previous studies. [PERSON] and [PERSON] (2019) explained that the deformation of the middle lamella, which leads to turgor loss and displacement of intercellular substances, causes textural changes [52]. The primary reasons for the decrease in firmness include the dissolution of pectin, turgor loss, and tissue shrinkage [53; 54; 55]. Although some water loss and solid gain can temporarily stabilize firmness, osmotic dehydration generally results in a softer texture in fruits and vegetables [56]. The type and concentration of the osmotic solution has a significant impact on the rate of osmotic dehydration and the food material's texture [30]. For example, increasing the osmotic solution concentration with added sugar can increase the hardness of fruits like mangoes due to sugar's structural strengthening effect [57]. However, excessively high concentrations can lead to structural deterioration and decreased firmness, as seen in studies on potatoes and cranberries [58; 59]. The use of firming agents, such as calcium lactate and calcium chloride, in the osmotic solution has been shown to enhance the firmness of fruits and vegetables by interacting with the carboxyl groups of pectin in the cell wall [57; 60]. [PERSON] and [PERSON] (2018) successfully used calcium lactate to achieve a better texture during osmotic dehydration [61]. In summary, while the firmness of strawberries generally decreased during osmotic dehydration, the changes were not significant until longer immersion times were reached. This indicates that the strawberries' structural integrity was mostly preserved throughout the osmotic dehydration process. The addition of calcium chloride (CaCl\({}_{2}\)) in the osmotic solution significantly helped maintain texture by forming chemical bonds with the plant tissue matrix, preventing textural deterioration. To assess the impact of the dehydration process on the visual appeal of the samples, the color parameters L*, a*, b*, and h were measured, and their values at the different immersion times are presented in Table 7. These color parameters were crucial in assessing the visual quality and any changes in the appearance of the strawberry slices due to the osmotic dehydration process. The values of L* indicates that the strawberries darkened initially, as the value dropped significantly at 170 min, remained stable until 270 min, and further increased at 300 min. The overall trend indicates that the strawberries darkened initially but regain some lightness with extended immersion times. The a* value increased, reaching its peak at 300 min with a value of 23.55. This increase suggests a more intense red color, which is desirable as it can be associated with ripeness. The b* value decreased significantly from 16.36 to 11.00 during the 170 min of the procedure, showing a reduction in yellowness.