# The Effect of Freeze-Drying on the Properties of Polish Vegetable Soups
## 3 Results and Discussion
The TPC and antioxidant activity after drying of beetroot and pumpkin soups did not change but the significant changes of color were observed (Tables 5 and 6). [PERSON] et al. [75] stated that the degradation of betacyamins leaded to other phenolic compounds which stimulated the increase of antioxidant activity of dried beetroot. The content of polyphenic compounds (TPC) after drying decreased significantly from 763 to 543 mg GAE/100 g d.m. for tomato soup and from 569 to 367 mg GAE/100 g d.m. for cucumber soups. It can be noticed that in the case of these soups, also the antioxidant capacity was the lowest. The significant decrease of TPC after storage was only observed for freeze-dried tomato soup. The investigation of freeze-dried soups showed that these products were characterized by good sensory attributes based on overall acceptability [33] but the food ingredients could significantly affect the sensory quality of instant soups [31]. The fresh soups and rehydrated soups were subjected to sensory analysis (Table 7). The investigated fresh commercial soups varied in the scores of sensory attributes. Thus, the change of these attributes of fresh soup and after rehydration of dried sample was analyzed. Sensory analysis showed the scores of color after rehydration of freeze-dried tomato, pumpkin, and cucumber soups  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Product**} & **Content of Polyphenolic Compounds** & **EC 50** \\  & **(TPC)** & **DPPH\(\bullet\)** \\  & **(mg GAE/100 g d.m. )** & **(mg/mL)** \\ \hline \multicolumn{3}{c}{**Tomato soup**} \\ \hline fresh & 3.95 \(\pm\) 0.14 **a** & 763 \(\pm\) 15 1  & 2.08 \(\pm\) 0.14 2  \\ dried & 4.17 \(\pm\) 0.08 3  & 543 \(\pm\) 22 2  \\ stored & 4.05 \(\pm\) 0.11  & 401 \(\pm\) 29  & - \\ \hline \multicolumn{3}{c}{**Beetroot soup**} \\ \hline fresh & 4.74 \(\pm\) 0.08 1  & 595 \(\pm\) 49  & 1.26\(\pm\) 0.08 1  \\ dried & 4.85 \(\pm\) 0.10 1  & 537 \(\pm\) 57  & 1.24 \(\pm\) 0.09 1  \\ stored & 4.80 \(\pm\) 0.12  & 521 \(\pm\) 47  & - \\ \hline \multicolumn{3}{c}{**Tomato soup**} \\ \hline fresh & 3.95 \(\pm\) 0.14 **a** & 763 \(\pm\) 15 1  & 2.08 \(\pm\) 0.14 2  \\ dried & 4.17 \(\pm\) 0.08 1  & 543 \(\pm\) 22 2  & 2.38 \(\pm\) 0.09 1  \\ stored & 4.05 \(\pm\) 0.11  & 401 \(\pm\) 29  & - \\ \hline \multicolumn{3}{c}{**Beetroot soup**} \\ \hline fresh & 4.74 \(\pm\) 0.08 1  & 595 \(\pm\) 49  & 1.26\(\pm\) 0.08 1  \\ dried & 4.85 \(\pm\) 0.10 1  & 537 \(\pm\) 57  & 1.24 \(\pm\) 0.09 1  \\ stored & 4.80 \(\pm\) 0.12  & 521 \(\pm\) 47  & - \\ \hline \multicolumn{3}{c}{**Cucumber soup**} \\ \hline fresh & 3.89 \(\pm\) 0.03 1  \\ dried & 4.20 \(\pm\) 0.07 1  & 367 \(\pm\) 55 [FOOTNOTE:2]Footnote 2: the different were lower by about 31-36% regarding fresh soups. The rehydrated beetroot soup showed the highest change of color in comparison to fresh soups. Sensory analysis confirmed the results obtained by the instrumental measurement of color attributes. The beetroot soups showed the highest change of color after drying. These changes negatively affected the color of the reconstituted soup evaluated by the panelists. The drying process did not affect the consistency of the pumpkin and beetroot soups after rehydration. The scores of taste and aroma, as well as overall quality, decreased the most for rehydrated tomato soup. The reconstituted freeze-dried soups were positively evaluated regarding taste, consistency, aroma, and overall quality, but the color of the soup significantly deviates from the color of fresh soups.