## 3 Results and Discussion
### Further Experimental Validation  
To further explore the mechanisms of WL and SG in the OD process, and then to investigate the transfer of antioxidants into strawberries, additional experiments were conducted at maximum glycerol concentration and temperature, with varying immersion times of 170, 190, 220, 270, and 300 min. These specific immersion times were selected based on the optimization results, which indicated that this range was critical for maximizing water loss and solid gain. Previous studies have consistently shown that immersion time plays a key role in determining dehydration efficiency [25; 28; 34]. By focusing on this time range, we aimed to gain deeper insights into how immersion time influences not only WL% and SG% but also the migration of natural antioxidants into the strawberries from the hypertonic osmotic chokeberry infusion, as well as the physicochemical parameters of the strawberries such as water activity (a\({}_{\text{w}}\)), moisture content, firmness, and color. In Figure 5, the relationship between immersion time and the two key responses, WL% and SG%, is presented. It is clear that both water loss and solid gain increase consistently with increasing immersion time. However, at immersion times of 220 and 270 min, these parameters remained practically stable before increasing slightly again at 300 min. This plateau indicates a temporary equilibrium in the osmotic dehydration process, where the rate of water being drawn out and solids being infused balanced out. The subsequent increase at 300 min suggests that extending the immersion time beyond the equilibrium period allows for further mass transfer, possibly due to deeper penetration of the osmotic solution into the fruit tissue and more extensive cellular breakdown. It has been reported that in the early stages of the osmotic process, the driving force between the product and the hypertonic solution is the strongest, resulting in more pronounced solid uptake rates [30]. As the process progresses, the osmotic pressure reduces  
Figure 5: Effect of immersion time on water loss (WL%) and solid gain (SG%). *: indicates \(p<0.05\), showing a statistically significant difference compared to the previous time point. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Experiments/** & **Predicted** & **Predicted** & **Composite** & **Experimental** & **Experimental** & **Prediction** & **Prediction** \\
**Runs** & **WL\%** & **SG\%** & **Desirability** & **WL\%** & **SG\%** & **Accuracy** & **(WL\%)** & **(SG\%)** \\ \hline
1 & 63.1979 & 20.2404 & 1.00000 & 55.2089 & 11.6984 & 87.37\% & 57.81\% \\
2 & 62.5173 & 16.8397 & 0.99799 & 54.8344 & 10.8976 & 87.69\% & 64.72\% \\
3 & 63.3045 & 16.5406 & 0.98121 & 42.9251 & 7.0793 & 67.81\% & 42.80\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Predicted and actual values of WL% and SG% under optimized conditions, and prediction accuracy. due to mass transfer between the phases. Over time, as water migrates from the sample to the medium and solute moves from the solution to the sample, the concentration gradient decreases, leading to lower dehydration rates [44; 45]. This is also consistent with [PERSON] et al. (2023) [3], who observed that water loss and solid gain were most pronounced in the early stages of osmotic dehydration. Moreover, this rapid initial loss can be attributed to the significant pressure difference between strawberry cells and the surrounding hypertonic solution, which promotes quick water molecule diffusion. As dehydration continues, this pressure difference diminishes, leading to structural changes in the strawberry tissue and approaching a dynamic equilibrium in mass transfer [34]. Finally, [PERSON] et al. (2019) [39] observed that solid gain reached equilibrium after 250 min in a 65 \({}^{\circ}\)Brix solution at 25 \({}^{\circ}\)C for kiwi fruit. These findings align with the optimization model, which predicted that immersion time, along with glycerol concentration and temperature, plays a crucial role in maximizing water loss and solid gain.