The activity of antioxidants and their mechanism of action is dictated by the structural features of the molecules involved, the system in which they are present as well as processing and storage conditions, among others.
Antioxidants can be classified into five classes based in their functions:
*Primary antioxidant
- Function essentially as free radical terminators
- Primary antioxidants have high catalytic properties and are involved in the elimination of millions of free radicals.
*Oxygen scavengers
- Oxygen scavengers effectively prevent oxidative damage in a wide range of food constituents such as oils and fats to prevent rancidity.
- Oxygen scavengers include inorganic materials that can absorb oxygen, as well as organic reactive materials that can consume oxygen through chemical reaction.
*Secondary antioxidants
- Important preventive antioxidants that function by retarding chain initiation
- Quench only one free radical and are quickly exhausted with no possibility of renewal
*Enzymatic antioxidants
- The antioxidant enzymatic system directly/indirectly contributes to defense against the ROS. Catalase, superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, etc., are enzymatic antioxidants.
*Chelating agents
- Chelators should function as preventive antioxidants by obstructing the activity of catalytic metals present in the system, thus eliminating the initial oxidation step.
Antioxidant Categories
