Effect of environmental factors [air and UV-C irradiation] on some fresh fruit juices

The present study was carried out to evaluate the effect of environmental factors (air and UV-C irradiation) on various common fruits juices (lemon, orange, papaya and grape). Total phenolics, total ascorbic acid (AA) content and antioxidant capability were determined in atmospheric air oxidation on fresh fruit juices, and the effect of UV-C irradiation on AA was investigated in both fresh fruit juices and commercial AA using RP-HPLC. The total phenolics content was found to be 92.46 +/- A 1.5, 41.53 +/- A 2.1, 138.56 +/- A 2.3 and 110.54 +/- A 3.9 mg/100 ml of lemon, orange, papaya and grape juices, respectively. DPPH radical-scavenging activity of the fresh juices was 94.53 +/- A 3.1, 82.36 +/- A 2.2, 94.65 +/- A 3.5 and 90.74 +/- A 2.6 percentage, whereas the 1-day-old fruit juices showed reduced scavenging activity when compared to fresh juices. Total phenolic (TP) and DPPH-scavenging activity were significantly decreased in the mean at < 0.05 level. Ascorbic acid (vitamin C) content of fresh fruit juices was determined through RP-HPLC; fruit juices that were kept in open container for 24 hrs and that were treated with UV irradiation have shown a decrease in AA content, when compared with control fresh juice samples. AA degradation increased with high significant differences at < 0.001 level, with the increase in oxidation time in atmospheric air and UV-C radiation.