## 3 Results
### Quality and Sensory Characteristics of Osmotically Dehydrated Pumpkin  
In Figure 2a-d total color change (\(\Delta E\) calculated by the Equation (6)), hardness (\(F_{max}\), N), vitamin C (%), and scores for total sensory quality (scale 1-9) of OD processed pumpkin cuts at the reference processing conditions (55 \({}^{\circ}\)C for 120 min) in solution of strained yoghurt whey or water (OD\({}_{\text{SY}}\) whey, OD\({}_{\text{Water}}\)) during storage at temperatures 5, 10, and 15 \({}^{\circ}\)C are presented. The pumpkin color change during storage was described by the increase of the total color change value \(\Delta E\) (Figure 2a1,a2). The maximum \(\Delta E\) value was calculated for OD\({}_{\text{SY}}\) whey and OD\({}_{\text{Water}}\) samples stored at the highest temperature of 15 \({}^{\circ}\)C (\(\Delta E_{max}\)= 12.71 and 13.81, respectively). At storage temperatures \(<\) 10 \({}^{\circ}\)C (after 90 days), OD\({}_{\text{SY}}\) whey samples presented significantly lower color change values (\(\Delta E_{max}\) = 7.12) (68%) compared to the respective OD\({}_{\text{Water}}\) samples (\(\Delta E_{max}\) = 12.02) (Figure 2a1,a2). The color change of respective non-processed fresh-cut pumpkin samples was described by \(\Delta E\) values of 6, 7, and 8 after storage of 7 days at 5, 10, and 15 \({}^{\circ}\)C, respectively. The hardness values of OD\({}_{\text{SY}}\) whey and OD\({}_{\text{Water}}\) samples were higher than the respective values of fresh-cut pumpkin samples showing that hardness was significantly increased after OD processing (15.24-15.94 N compared to 11.50 N). However, there were no statistically significant differences between OD\({}_{\text{SY}}\) whey and OD\({}_{\text{Water}}\) samples (\(p<\) 0.05) (Figure 2b1,b2). The hardness of both osmotically dehydrated samples decreased with storage time (\(p<\) 0.05). The effect of storage temperature was not significant for OD\({}_{\text{SY}}\) whey (10-15 \({}^{\circ}\)C) and OD\({}_{\text{Water}}\) samples (5-15 \({}^{\circ}\)C) (\(p>\) 0.05). The hardness values of OD\({}_{\text{SY}}\) whey and OD\({}_{\text{Water}}\) samples after 90 days of storage at temperatures from 5 to 15 \({}^{\circ}\)C were approximately 12.75 and 10.91 N, respectively. The hardness of fresh-cut pumpkin samples decreased from the initial value of 11.50 to 6.70-9.68 N after 7 days storage at 5-15 \({}^{\circ}\)C.  
The vitamin C content was significantly increased after OD processing (both in SY Whey and water solutions). The improved retention (after 90 days of storage), accomplished with the application of an osmotic pretreatment, is illustrated in Figure 2c1,c2, (95 and 90% vitamin C retention for OD\({}_{\text{SY}}\) whey and OD\({}_{\text{Water}}\) samples, respectively). Fresh-cut pumpkin samples presented 20%, 25%, and 30% vitamin C loss, after 7 days of storage at 5, 10, and 15 \({}^{\circ}\)C, respectively. Based on the kinetic modeling of each quality index (presented above), the rates of quality deterioration \(k_{color}\), \(k_{texture}\), \(k_{vitaminC}\), \(k_{sensory}\) (Equations (6)-(9), respectively) were calculated (Table 3). The temperature dependence of the rates was then modelled using the Arrhenius equation (Equation (10)) (described by the activation energy value \(E_{a}\)) (Table 3).