Comparison of some biochemical characteristics of different citrus fruits

The goal of this investigation was to evaluate the antioxidant properties o f some citrus fruits. The contents of dietary fibre, total polyphenols, ess ential phenolics, ascorbic acid and some trace elements of lemons, oranges and grapefruits were determined and compared with their total radical-trapp ing antioxidative potential (TRAP). There were no significant differences i n the contents of total, soluble and insoluble dietary fibre in the studied peeled fruits or their peels. The contents of total, soluble and insoluble dietary fibre in peels were significantly higher than in peeled fruits (P < 0.05 in all cases). The peeled lemons, oranges and grapefruits contain 16 4 +/- 10.3; 154 +/- 10.2 and 135 +/- 10.1 and their peels 190 +/- 10.6; 179 +/- 10.5 and 155 +/- 10.3 mg/100 g of total polyphenols, respectively. The content of total polyphenols in peeled lemons and their peels was signific antly higher than in peeled oranges and grapefruits and their peels, respec tively. The content of total polyphenols in, the peels was significantly hi gher than in peeled fruits (P < 0.05 in all cases). The same results were o btained in the investigation of essential phenolics and ascorbic acid. The content of Fe in peeled lemons and their peels was significantly higher tha n in peeled oranges and grapefruits and their peels, respectively. Also the TRAP was significantly higher in peeled lemons and their peels than in pee led oranges and grapefruits and their peels, respectively. In all three fru its, the TRAP was significantly higher in peels than in peeled fruits (P < 0.05). In conclusion, lemons possess the highest antioxidant potential amon g the studied citrus fruits and are preferable for dietary prevention of ca rdiovascular and other diseases. The peels of all citrus fruits are rich in dietary fibres and phenolic compounds and suitable for industrial processi ng. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.