# Bioactive Vitamin C Content from Natural Selected Fruit Juices
## 3 Results and Discussion
### Vitamin C Content in Juices Stored in Plastic Containers
The vitamin C content of apple juice at storage temperature t\({}_{3}\) = \(-\)18 \({}^{\circ}\)C in plastic containers was as follows: 1 st day: 19.32%; 2 nd day: 20.45%; 3 rd day: 21.59%; 7 th day: 23.86%. The vitamin C content in apple juice at storage temperature t\({}_{3}\) = \(-\)18 \({}^{\circ}\)C in glass containers differed little from those in plastic containers. In plastic packaging regarding winter pear juice at storage temperature t\({}_{1}\) = 4 \({}^{\circ}\)C, the vitamin C content decreased rapidly after the 1 st day (5.07%) (Figure 4e). On the following days, the decrease was only slightly different from the change after the 1 st day (2 nd day: \(-\)5.22%; 3 rd day \(-\)5.97%). The largest decrease from the original content in juice stored in plastic containers was recorded after day 7 (\(-\)7.46%). At t\({}_{2}\) = 23 \({}^{\circ}\)C, during the whole storage time, the vitamin C content in winter pear juice decreased in the plastic containers as follows: 1 st day: \(-\)5.22%; 2 nd day: \(-\)5.97%; 3 rd day: \(-\)5.97 %; 7 th day: \(-\)7.46% (Figure 4e). Concerning days 2 and 3, there was no further decrease in vitamin C content in winter pear juice stored in plastic containers. Figure 4e shows the decrease in vitamin C values when winter pear juice is stored in a freezer at t\({}_{3}=-18\)\({}^{\circ}\)C in plastic containers. The vitamin C content decreased in the plastic container (change of 2.99%) on the first day of storage. After the 2 nd day of storage, the values were balanced in both types of packaging material (change of 4.48%). After the 7 th day of storage, the vitamin C content of the juice stored in plastic containers decreased by a further 1.49% (3 rd day: \(-5.82\%\); 7 th day: \(-7.46\%\)). The vitamin C values of autumn plum juice stored at refrigeration temperature (t\({}_{1}=4\)\({}^{\circ}\)C) in plastic packaging materials can be seen in Figure 4f. However, a significant decrease after the 1 st day of storage was observed in juice stored in plastic packaging material (\(-8.45\%\)). The percentage decreases in vitamin C on the following days in plastic packaging were as follows: 1 st day: \(-8.45\%\); 2 nd day: \(-8.45\%\); 3 rd day: \(-9.86\%\); 7 th day: \(-10.28\%\). At t\({}_{2}=23\)\({}^{\circ}\)C, when the plum juice was stored in glass, the vitamin C values in both packaging materials degraded after the first day of storage as much in the glass container as in the plastic container (Figure 4f). As reported by [PERSON] and [PERSON] [73] and [PERSON] and [PERSON] [2], higher temperatures during storage conditions can negatively affect vitamin C content. As a consequence, on the 2 nd day, the rate of degradation of vitamin C in the juice stored in the plastic material increased by 5.63% compared with the degradation in the juice stored in the glass material, by 1.41% on the 3 rd day, and by 0.99% after 1 week. Figure 4f shows the storage of plum juice at freezing temperature (t\({}_{3}=-18\)\({}^{\circ}\)C) in plastic packaging materials. The vitamin C content at storage temperature t\({}_{3}=-18\)\({}^{\circ}\)C in the plastic packaging decreased as follows: 1 st day: \(-7.04\%\); 2 nd day: \(-8.45\%\); 3 rd day: \(-9.86\%\); 7 th day: \(-10.56\%\). Factors were examined regarding the vitamin C content of fruit juices. The comparison of results (Figure 4a-e) showed that in fruit juices at t\({}_{1}=4\)\({}^{\circ}\)C, stored in plastic containers, there were losses of vitamin C in 24 h in the range of 2.4-17.4%, in 48 h in the range of 5.2-25.3%, and in 3 days in the range of 6.0-39.0% of the value. In fruit juices, by increasing the storage temperature to t\({}_{2}=23\)\({}^{\circ}\)C, stored in plastic containers, the losses in vitamin C values within 24 h were in the range of 5.2-22.17%, within 48 h in the range of 5.9-25.9%, and within 3 days in the range of 6.0-38.7% of the value.