Author: Borut POLJŠAK
Type of paper: Original scientific paper
Issue: Volume 2 | number 1 – 2008
Abstract: The ageing process is influenced by increased oxidative stress, which causes damage to cellular components, such as DNA, proteins and lipids. Many studies claim that use of antioxidant might prevent intracellular oxidative damage formation and thus decrease the incidence of age related diseases (cancer, cardiovascular diseases, cataract…). The level of endogenous antioxidants cannot be deliberately increased. However, the level of exogenous antioxidants intake can be increased by consuming more fruit, vegetables or their juices, which are a rich source of many different antioxidants. Today consumers are aware of a healthy way of living, thus the antioxidant status of a product can be important information in the decision of purchase.
We measured the antioxidant status in selected fruit juices and teas. Since each exogenous antioxidant (vitamin C, E, beta carotene) prevents oxidation or quenches free radicals by donating one electron or H-. For this reason the amount of active H (H-) was determined as an indicator of the total antioxidant potential. Besides, the intake of H- with natural products is better than with synthetic ones, because fruits and vegetables contain many different antioxidants which can regenerate each other. It was concluded that the total antioxidant potential, measured as the relative amount of H- (partial H pressure), is a better indicator of the antioxidant status of a specific food product, than the determination of only one specific antioxidant, eg. vitamin C, E or beta carotene. The results indicate significant differences in the rH level among different drinks. The highest value of active hydrogen was determined in tomato juice, red grapes juice, carrot, blackcurrant, nectar of strawberry, apple and grapes, orange juice, pineapple juice, sour cherry nectar and blueberry tea. There is much active hydrogen also in the pear nectar, apricot nectar, peach nectar, banana nectar, nectar made of seven juices and five mashes, but these are with added synthetic antioxidants (ascorbic acid) that contribute to the increased value of active hydrogen. The antioxidant potential of teas is lower than the antioxidant potential of the majority of juices. However, the portion of active hydrogen is in all selected beverages is much larger than in potable water.