## 2 Materials and Methods
### Osmotic Dehydration of Tomatoes and Spinach Leaves  
Osmotic dehydration of cherry tomatoes and spinach leaves was conducted in a pilot scale setting. A cylindrical (\(\O 28\ \times\ 60\) cm) stainless steel tank of 100 L was used. The tank was fitted with spigots that allowed draining of the solution. Stirring was provided using an electrical motor stirrer fitted with a paddle and submerged in the solution. To avoid damaging the delicate plant tissues, stirring was kept to a minimum and the motor was set at a rotational speed of 120 rpm. Where required, heating capabilities were provided to the tank using a submerged stainless steel helical tube, and heated via a continuous circulation of water from a 3 kW water bath. The temperature of the solution was monitored with a thermocouple.  
The solution required for each osmotic dehydration was prepared in situ within the stainless steel tank by dosing the ingredients using a high-capacity electronic balance.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Ingredient** & **Processing Characteristics** & **Mass Percentage in the Product** \\ \hline \multicolumn{3}{c}{**OD-treated tomato-based ready-to-eat salad product**} \\ \hline OD-treated tomatoes & \
\begin{tabular}{c} Halved cherry tomatoes were osmoltically \\ dehydrated for 180 min at 35 \({}^{\circ}\)C \\ Feta cheese trimmings were osmotically \\ dehydrated for 60 min at room \\ temperature in an osmotic medium \\ containing 40\% glycerol, and further \\ air-dried for 24 h at 50 \({}^{\circ}\)C \\ Am-dried olives \\ \end{tabular} & 70\% \\ \hline \multicolumn{3}{c}{**OD-treated spinach-based ready-to-eat salad product**} \\ \hline OD-treated spinach leaves were osmotically &
\begin{tabular}{c} Spinach leaves were osmotically \\ dehydrated for 60 min at \\ room temperature \\ Feta cheese trimmings were osmotically \\ dehydrated for 60 min at room \\ temperature in an osmotic medium \\ containing 40\% glycerol, and further \\ room temperature in an osmotic medium \\ containing 40\% glycerol, and further \\ air-dried for 24 h at 50 \({}^{\circ}\)C. \\ Roasted ground peanuts \\ \end{tabular} & 25\% \\ \hline \hline \end{tabular}
\end{table}
Table 1: OD-treated tomato and spinach-based ready-to-eat (RTE) salad product formulation and characteristics (the serving size was 100 g of net product weight).  
Gentle heating was employed (temperature set at 35 \({}^{\circ}\)C and room temperature for tomatoes and spinach, respectively) to ensure the homogeneous dissolution of the osmotic medium constituents. The osmotic dehydration medium for the OD of cherry tomato contained 60% \(w/w\) glycerol, 10% \(w/w\) vinegar (8% acetic acid), 10% \(w/w\) maltodextrin (DE 47), 3.5% sodium chloride, and 1.5% calcium chloride [31]. The osmotic dehydration medium for the OD of spinach contained 60% \(w/w\) glycerol, 10% \(w/w\) maltodextrin, 1.5% calcium chloride, 1% sodium chloride, 2.5% vinegar and 0.05% \(w/w\) sodium metabisulfite [25].  
The vegetables were manually loaded and unloaded in the tank. After OD treatment, the vegetables were ringed with a centrifugal household vegetable wringer and placed on a perforated rack for 30 min to drain off excess osmotic solution.