4. Conclusions
This paper aimed to determine the comparative
antioxidant activity (using the DPPH free- radical
method) of some natural, fresh vegetable and fruit
juices (pink grapefruit, apple, beetroot, red cabbage,
tomatoes). Knowing that vitamin C is one of the most
powerful natural antioxidants we try to establish a
correlation between antioxidant activity and vitamin
C content of the analysed juices. The results of
experiments may be summarized as:
Between fruits and vegetables examined, the
highest content of vitamin C is present in
pink grapefruit, followed by the beetroot and
red cabbage and the lowest vitamin C content
is found in apple.
Vitamin C concentration is higher in the
juices than in the raw materials, the richest in
ascorbic acid being pink grapefruit juice,
followed by the beetroot juice. The lowest
concentration of vitamin C was obtained for
apple juice.
For all the analysed samples the antioxidant
activity varies in direct proportion with the
vitamin C concentration.