# Quality Assessment of Natural Juices and Consumer Preferences in the Range of Citrus Fruit Juices
## 3 Results and Discussion
### Physicochemical Evaluation of the Commercial juice and Juices Made with a Juicer or Squeezer
The highest sugar level for commercial orange juice \"O\" and ES juice was 10.2 g. According to the commercial juice manufacturer \"O\", the content of all sugars is 10 g. A slightly higher sugar level was determined for EW juice--10.15 g. The lowest values were recorded for HS juice--8 and HW juice--7 (see Table 2), which is consistent with the results of the organoleptic evaluation, in which juices from oranges from Spain were rated as the least sweet. The determination of sugars in juices was also handled by [PERSON] et al. [52], who used high-performance liquid chromatography (HPLC). The author indicated that in orange juice the content of fructose was 1.82 \(\pm\) 0.20 g/100 cm\({}^{3}\), glucose 1.56 \(\pm\) 0.20 g/100 cm\({}^{3}\), sucrose 3.14 \(\pm\) 0.13 g/100 cm\({}^{3}\), providing a total sugar content of 6.51 \(\pm\) 0.38 g/100 mL. From the results presented in this work for commercial orange juice, the content of fructose was 2.22 \(\pm\) 0.08 g/100 cm\({}^{3}\), glucose 2.04 \(\pm\) 0.16 g/100 cm\({}^{3}\), and sucrose 3.69 \(\pm\) 0.09 g/100 cm\({}^{3}\); the total content of sugars was 7.97 \(\pm\) 0.24 g/100 cm\({}^{3}\). Comparing these data with the information provided by [PERSON] et al. [52], the amount of determined sugars in the presented work was higher. An important parameter in the characterisation of juices is the dry-matter content. Comparable values of dry-matter content were obtained for ES juices--10.88%, commercial orange juice 10.75%, and squeezed orange juice from Egypt 10.32%. Significantly lower values of dry matter were noted for orange juice from Spain, squeezed in a juicer--8.75%, and a squeezer--7.25% (see Table 2). The above data differentiate the water content of the juices depending on where the fruit came from. Smaller differences were observed in juices obtained by the squeezing method in the squeezer and juicer. The vitamin C content of juices, according to the _Good Production Practice Guide for the Jucing Industry_[49], should be a minimum of 200 mg/L. From the research conducted in the work presented, more vitamin C was contained in juices from oranges originating in Spain than in juices from oranges originating in Egypt. Juices from oranges squeezed with a juicer showed more vitamin C than juices squeezed with a squeezer (see Table 3). The vitamin C content of commercial juice was significantly higher than that stated by the manufacturer on the package (23.8 units). This inconsistency may be due to the deliberate administration of higher amounts of vitamin C during juice production. As reported by [PERSON] et al. [53], the content of vitamin C during the production process may decrease due to its perishability, hence higher amounts are given so that the declared amount is not underestimated. In the work presented it was observed that the vitamin C content decreased slightly after pasteurisation at 72 \({}^{\circ}\)C. [PERSON] et al. [54] reported that the heating process in thermal pasteurisation might have caused an increase in the total acids. The main reason of the increase of the total acid in juice might be the generation of acids from carbohydrate according to the oxidation [55]. This did not agree with our results. The biggest difference between the vitamin C content in the juice before and after pasteurisation was recorded for commercial juice (3.2 mg/100 cm\({}^{3}\)). For orange juice squeezed with a squeezer, for both Egyptian and Spanish juice, the vitamin C content was virtually unchanged (see Table 4). Studies of the effect of temperature on the physicochemical changes of orange juice were also conducted by [PERSON] et al. [56]. Storage time, temperature and microbial contamination significantly affected the flavour of fruit juice [57]. Pasteurisation was carried out at 70 \({}^{\circ}\)C for 7.2 s, and there was no significant reduction in vitamin C either. [PERSON] et al. [58] obtained larger changes in vitamin C content, who conducted fixation at a higher temperature (90 \({}^{\circ}\)C/1 min).