Abstract :
[en] Antioxidants are enzymes, non-enzymatic proteins, minerals micronutrients, vitamins, phenolic compounds, pigments and others. Polyphenols have the ability to reduce or prevent damage caused by free radicals promoting positive effects on human health due to their antioxidant capacity. In this study we evaluated the content of polyphenols from several commercial biological (n = 6) and conventional juices (n = 6 ) (orange, blackcurrant, apple, grapes, tomato, carrot, pomegranate, lemon, grapefruit juices) and we determined the antioxidant effect by inhibition of the superoxide anion production measured by chemiluminescence technology. Conventional juices (orange, apple, tomato, pomegranate, lemon, grapefruit juices) showed more total polyphenolics (+ 32%), more flavan-3-ols (+ 67%) and more flavonols (+ 42%) than the same biological juices. The presence of anthocyanins was reported in juices made with blackcurrant, pomegranate and grapes only, with values above 50 µg/mL, regardless of their nature. Surprisingly, chemiluminescence results showed an inhibition in superoxide anion production by 51% for biological juices vs 23% in conventional ones. The correlation between total polyphenol content and antioxidant capacity of all the juices was r = 0.83 (r2 = 0.7). The fact that there is less polyphenols and higher antioxidant activity in bio juices could be related to the concentration and the type of polyphenol present.
