المجلة الدولية للعلوم والتقنية

The concentrations of Vitamin C, also known as L-ascorbic acid, in eleven different types of fresh and frozen fruits were determined by titration method. The effects of some conditions such as time of freezing on the Vitamin C contents were studied. Samples were collected from farms close to Janzour overall seasons. Each sample or a part of it was squeezed to get juice and centrifuged; the volume and the weight of the supernatant liquid were taken. The estimation of vitamin C concentrations were done for fresh samples, after 12, 24, 48 and 72 hours and frozen samples after 1, 2, 3 and 4 weeks. From obtained results, the concentrations of vitamin C were decreased with increasing time of experiments for fresh and frozen samples with statistically significant deference. The highest concentration was found in blood oranges and lowest concentration noticed with apple for fresh and frozen samples. Meanwhile, the concentration of vitamin C was higher in frozen sample than fresh sample without significant differences. In conclusion, the freezing method for limited time (month for example) is the best way to maintain the concentration of vitamin C because it works to inhibit the activity of oxidative enzymes and break down the vitamin C............. Keywords: .......Vitamin C, Frozen fruits; Fresh fruits; titrimetric method; L-ascorbic acid.