What is Oxidation?
L ‘ oxidation is the chemical process in which a substance loses electrons (oxidizes) in favor of another nearby substance that buys them (is reduced), in the context of a combined process known as oxidation-reduction or redox .
The oxidation process is one of the most common and frequent causes of alterations, even substantial ones, in the color, aroma, texture, taste and nutritional content of foods during the processes of production, distribution and preparation of the same.
Role of Antioxidants
The antioxidants have the function to prevent or interrupt the oxidation process , significantly prolonging the shelf-life (expiry date) of foods and acting accordingly as preservatives .
Antioxidants: Chemical Classification
Antioxidants can be chemically classified into:
- Primary and secondary.
Primary antioxidants are reducing compounds that oxidize in place of food, reacting themselves with free radicals and converting them into more stable compounds (an example is given by vitamin E ).
Secondary antioxidants, on the other hand, are compounds capable of reducing primary antioxidants after they have reacted with free radicals, restoring them and making sure that they continue to perform their function (an example is given by vitamin C against E) .
- Enzymatic (endogenous) and non-enzymatic ( exogenous).
Enzymatic antioxidants are compounds produced by the body to defend itself against the attack of free radicals; these include catalases, glutathione peroxidase and superoxide dismutase (SOD).
Non-enzymatic antioxidants, on the other hand, are compounds introduced into the body through food; these include vitamins A, C, E, polyphenols (in turn divided into phenolic and flavonoid acids ), carotenoids,
Antioxidants: Classification based on Origin
Antioxidants can also be distinguished on the basis of their origin; thus three groups derive:
- The natural antioxidants.
Vitamins C and E (respectively ascorbic acid and tocopherol ) belong to this category . When possible, we try to favor this type of antioxidants, because in addition to being considered safe in food, they also have anticancer effects and inhibit oxidative reactions which, in excess, are harmful to the body.
- The antioxidants nature-identical.
These antioxidants are obtained by chemical synthesis by copying the formula of the natural ones. They are economically less expensive compounds. An example is the chemical synthesis of ascorbic acid .
- The synthetic antioxidants.
They are antioxidants that do not exist in nature, and are the most contested and discussed, despite being approved at European level. An example p given by BHA and BHT .