# Bioactive Vitamin C Content from Natural Selected Fruit Juices
## 3 Results and Discussion
### Vitamin C Content in Juices Stored in Plastic Containers
[84], the higher the temperature, the higher the loss of vitamin C. The contents of vitamin C in mandarin-clementine juice stored in a plastic container in a freezer (t\({}_{3}\) = \(-\)18 \({}^{\circ}\)C) obtained by the analysis are shown in Figure 4b. Recorded percentage changes of vitamin C content in plastic containers were as follows: 1 st day: \(-\)20.00%; 2 nd day: \(-\)26.09%; 3 rd day: \(-\)43.48%; 7 th day: \(-\)49.13%. During the entire time of storage of mandarin juice at freezing temperature in plastic and glass packaging, the differences between the percentage changes in vitamin C content were only minimal (identical after the 2 nd day of storage). The biggest difference was achieved after the 3 rd day of storage when the vitamin C content in the juice stored in glass containers was 2.17% higher than in plastic containers. [PERSON] [53] established that frozen concentrated orange juice (FCOJ) and reconstituted FCOJ always have the highest levels of vitamin C compared to freshly squeezed or not-from-concentrate (NFC) juice and are above the 100% US RDA value. In mandarin juice, the decrease in total vitamin C as a function of the temperature t\({}_{2}\) (23 \({}^{\circ}\)C) and t\({}_{3}\) (\(-\)18 \({}^{\circ}\)C) was found to be approximately the same (Figure 4b). The juice from late peach, stored in the refrigerator (t\({}_{1}\) = 4 \({}^{\circ}\)C) in plastic packaging, had a lower vitamin C content than citrus fruit (3-4 times). Vitamin C decrease in glass packaging was significantly slighter (1 st day: \(-\)2.35%; 2 nd day: \(-\)5.88%; 3 rd day: \(-\)11.77%; 7 th day: \(-\)17.65%) (Figure 4c). The loss of vitamin C in plastic packaging was 11.77% higher than in glass packaging after 7 days of storage. The loss of vitamin C over time varies from one species to another in similar storage environments [33]. For room temperature (t\({}_{2}\) = 23 \({}^{\circ}\)C) in peach juice stored in plastic packaging materials, the decrease in vitamin C content was analysed: 1 st day: \(-\)9.41%; 2 nd day: \(-\)9.41%; 3 rd day: \(-\)14.12; 7 th day: \(-\)17.65% were lower values than in glass packaging. Except for the 2 nd day of storage when the loss of the content of vitamin C in the juice stored in the plastic packaging material was 1.18% lower than in the glass. After the 7 th day of storage, the vitamin C value in the juice stored in plastic packaging material was 1.77% lower than in glass. In plastic packaging, when storing peach juice at t\({}_{3}\) = \(-\)18 \({}^{\circ}\)C, there was a significant decrease in vitamin C content as early as the 2 nd day of storage (1 st day: \(-\)4.71%; 2 nd day: \(-\)8.82%; 3 rd day: \(-\)18.24%; 7 th day: \(-\)23.53%) (Figure 4c). Vitamin C content in peach juice at storage temperature t\({}_{3}\) = \(-\)18 \({}^{\circ}\)C in plastic containers was almost the same as in glass packaging. The vitamin C content of the juice of winter apple juice at storage temperature t\({}_{1}\) = 4 \({}^{\circ}\)C decreased in the plastic packaging as follows: 1 st day: \(-\)6.82%; 2 nd day: \(-\)17.05%; 3 rd day: \(-\)19.32%; 7 th day: \(-\)22.27% (Figure 4d). The effect of storage conditions (temperature and days of storage) on vitamin C content was detected as early as the second day at t\({}_{1}\) = 4 \({}^{\circ}\)C, and the vitamin C content decreased with increasing days of storage. [PERSON] and others [16] pointed out that storage conditions influenced the quality and nutritional properties of the fruit. In apple juice stored at room temperature (t\({}_{2}\) = 23 \({}^{\circ}\)C) in plastic packaging material, a significant decrease in the vitamin C content was observed already after the 2 nd day of storage (\(-\)17.05%). The overall decrease after 7 days of storage was 22.05% in plastic containers. Fruits generally showed a gradual decrease in ascorbic acid content with increasing temperature or storage time [73]. Figure 4d indicates the reduced vitamin C values when apple juice is stored in the freezer at t\({}_{3}\) = \(-\)18 \({}^{\circ}\)C in plastic packaging material.