Ruolo delle sostanze antiossidanti negli alimenti

Antioxidants are compounds present in food at low concentrations and able to both protect oxidable substrates and countenrbalance the negative effects that the reactive oxygen species (ROS) cause in the human body (reduction of the risk to develop cardiovascular pathologies, cancer and degenerative diseases that accelerate the aging processes). In foods, lipid oxidation is a degradation regarding the unsaturated fatty acids that react with oxygen through several mechanisms such as chemical autoxidation, action of lipoxigenases, photoxidation, and others. Autoxidation is the main oxidation process and proceed via initiation, propagation, and termination steps leading to the hydroperoxide formation. Hydroperoxides could degraded into low molecular weigh compounds such as alcohols, aldehydes, ketons, acids and other low reactive compounds that negatively influence quality, nutritional value and shelf life of foods. Antioxidants are known to act at different levels of the lipid oxidation. They may act in several ways: they can decrease the oxygen concentration, intercept the singlet oxygen, slow the initiation step by scavenging the first free radicals, break the reaction chain to prevent the hydrogen subtraction, and decompose primary products of oxidation into non-radical products. This work reports the results of two studies on the phenolic fraction and potential antioxidant activity of virgin olive oils and red wines produced in Apulia region. Oils were extracted from olives produced at Cerignola and Torremaggiore using a two phase continuous system. Results showed a different phenolic composition of the oils and a good linear correlation between phenolic content and antioxidant activity. Wines were produced from Primitivo grapes pickled at the so-called technological maturity in a vineyard located at Manduria (Taranto). Nine different maceration techniques were applied. Results showed that the addition of tannins from skins and seeds and the saignée allowed to obtain high phenolic concentrations in wines. Among the methods used to assess the antioxidant activity, β-carotene seems to be effective.