# Shaping the Properties of Osmo-Dehydrated Strawberries in Fruit Juice Concentrates
## 3 Results and Discussion
### PCA Results  
In order to determine differences and similarities (correlations) [14] between the analyzed dehydrated fruits in terms of the type of osmotic agent and mass exchange indices (water loss, solid gain, weight reduction, dry matter content) and physical properties assessed in terms of compression force and work, as well as composition (the content of total polyphenols, anthocyanins, ascorbic acid, and sugars, as well as antioxidant activity), a major component analysis with classification (PCA) for strawberries dehydrated for 3 h was performed (Figure 11a). The main components (PC1 and PC2) explain 98.5% of the variability in the properties of dehydrated fruit. Figure 11: PCA analysis: (**a**) PCA loading plot of two principal components, (**b**) score plot presenting analyzed samples in term of PC1 vs. PC2. Markings: DM—dry matter content, WL—water loss, SG—solid gain, Aw—water activity; L*, a*, b*, \(\Delta\)E—color parameters. Red lines indicate active data included in the PCA analysis, blue lines - additional data. The red line on (**b**) concerns the separation of a group of data with a similar effect of osmotic agent on the examined physicochemical indicators. Weight reduction was strongly (r\({}^{2}\) = 0.97, data not shown) positively correlated with fruit water loss, while relatively low solid gain values had no effect on these indicators (Figure 11a), which confirms that water migration from the samples to the surroundings was predominately mass flux during osmotic dehydration. The water activity of dehydrated strawberries was strongly correlated with solid gain and sucrose content (r\({}^{2}\) = 0.96 and 0.99). Such results are very interesting when comparing them with previously mentioned results, despite the fact that water loss dominated solid gain and the uptake of solids participated in the creation of water activity value as well. It was shown that the compressive force F\({}_{\rm max}\) and the compressive work correlated negatively with dry matter content (r\({}^{2}\) = \(-\)0.81 and \(-\)0.85, respectively). Although osmotically dehydrated products are not hard and crunchy, appropriate softness is desirable in them and the changes in their mechanical properties may be mainly related to changes in the tissue structure caused by osmotic dehydration. Lower dry matter content could be associated with smaller changes in structure, a lower solid gain, greater firmness, and higher values of mechanical properties. DPPH and ABTS indices were strongly positively correlated with the content of anthocyanins (r\({}^{2}\) = 0.80 and 0.93), while DPPH also correlated with the content of total polyphenol content (r\({}^{2}\) = 0.66) and both negatively correlated with solid gain (r\({}^{2}\) = \(-\)0.89 and \(-\)0.93). The negative correlation between solid gain and antioxidant activity shows that the role of osmotic agents represents a protective role rather than being a source (per se) of biological compounds. It was also interesting that the total polyphenol content was strongly correlated with the vitamin C content (r\({}^{2}\) = 0.94) of the dehydrated strawberries. Among the color parameters, color lightness L* was positively correlated with solid gain (r\({}^{2}\) = 0.85) and sucrose content and negatively correlated with mass and water loss (r\({}^{2}\) = \(-\)0.80 and 0.92) and anthocyanin content (r\({}^{2}\) = \(-\)0.91). The increased content of anthocyanins in the chokeberry juice concentrate caused the greatest darkening and color changes in dehydrated strawberries (Figure 11a, Table 2, Figure 6). The color parameter a* correlated with glucose and fructose content (r\({}^{2}\) = 0.90 and 0.95) and b* correlated with vitamin C and fructose content (r\({}^{2}\) = 0.75 and 0.79). The color parameters a*, b*, and \(\Delta\)E and the fructose content had the least influence on the PCA (the shortest lines in the PCA diagram) and did not correlate significantly (\(p\) < 0.05) with any of the factors.