What are Antioxidants?
Antioxidants may be defined as substances that when present in food, delay, control or inhibit oxidation and deterioration of food quality. Antioxidants are compounds that inhibit oxidation.
An antioxidant is a substance which when present at low concentrations compared to those of oxidisable substrates, significantly delays or inhibits oxidation of that substrate. Use of antioxidants in food was unintentionally practiced since antiquity, when populations living in hot climates in countries like India.
Antioxidant herbal medicines protect against oxidation and free radical damage. The term ‘antioxidant’ is derived from the Greek anti, meaning ‘against’, and the English oxidant, meaning ‘a substance that can cause oxidation or is oxidising in action.
Synthetic antioxidants are of potential use in chemistry, the food industry and medicine. Some of these compounds retain a functional group chemistry analogous to that of “natural” antioxidants and introduce new chemical groups that enhance their range of cellular action or make them available to cell sites hitherto restricted. Alternatively some synthetic antioxidants bear no structural analogy with natural antioxidants and exhibit a high reactivity toward reactive oxygen species and display selective protection in certain tissues.
A large number of synthetic antioxidants are available for the stabilisation of nonfood materials such as plastics, rubber and polymers. However, the use of synthetic antioxidants in foods requires that different aspects be taken into consideration including technological necessity, the toxicology of lipid oxidation products and the toxicology of antioxidants.
Plants are persistently the generous source to supply man with valuable bioactive substances and thus different plant products are being evaluated as natural antioxidants to improve the overall quality of meat and meat products. The focus for using natural antioxidants for the effective preservation of meat or meat products has almost exclusively been on the use of plant phenolics or phenolic containing extracts.
Phenolic compounds are plant secondary metabolites commonly found in herbs and fruits, vegetables, grains and cereals, tea, coffee and red and white wines. Phenolic acids are phenols that possess carboxylic acid functionality. Phenolic compounds can be broadly divided into two categories. Among phenolic compounds found in plants, flavonoids are the most widely studied class of polyphenols with respect to their antioxidant and biological activities.
Antioxidant – Mechanism of Action
Antioxidants are substances that at low concentrations retard the oxidation of easily oxidizable bio-molecules, such as lipids and proteins in meat products, thus improving shelf life of products by protecting them against deterioration caused by oxidation.
According to their mechanism,
- Antioxidants that act as radical scavengers. Examples of antioxidants which scavenge free radicals are phenolic compounds, ligands, flavonoids and phenolic acids.
- Antioxidants that react with transition metals to form complexes and thus avoid the catalytic effect of the metals in the oxidation process.
- Antioxidants that decompose peroxides and produce stable substances which are unable to produce radicals such as selenium containing glutathione peroxidase an antioxidative enzyme which inactivate free radicals and other oxidants, particularly hydrogen peroxide.
- Antioxidants which inactivate the singlet form of oxygen, In the presence of photosensitizers such as chlorophyll and pheophy-tins, singlet oxygen may be formed from ordinary triplet oxygen by the action of light.
- Antioxidants which prevent the enzymatic activity required for auto oxidation. Examples are flavonoids, phenolic acids and gallates which deactivates the lipoxygenase.
Antioxidants Health Hazards
Humans are impacted by many free radicals both from inside our body and surrounding environment, particularly reactive oxygen species generated in living organisms during metabolism. Antioxidants may have a positive effect on human health since they can protect the human body against deterioration by free radicals.
However, the use of synthetic antioxidants must be strictly controlled due to potential health hazards. Hence, the search for natural antioxidants as safe alternatives to synthetic products is important in the food industry. Therefore the use of natural antioxidants available in food and other biological substances has attracted significant interest due to their presumed safety and nutritional and therapeutic values.
Frequently Asked Questions on Examples of Antioxidants
How do antioxidants work?
Antioxidants are molecules in your body which fight free radicals. Free radicals are molecules that can cause damage if the body has too high levels of them. Antioxidants are molecules that neutralize free radicals, molecules that are unstable and can damage the cells.
Do antioxidants detox your body?
Antioxidants, and benefits from them. Your body has a natural way to “detoxify” or remove the contaminants it is exposed to everyday. Antioxidants function inside the body like clean-up and protective agents, fighting the free radicals which cause unwell symptoms and diseases.
What does an antioxidant do for the human body?
Scientists assume that molecules that are called free radicals may lead to ageing. These may also play a role in illnesses such as cancer, diabetes and heart disease. Antioxidants are chemicals that enable the free radicals to stop or restrict damage. The body uses antioxidants to put free radicals into balance.
Is Zinc an antioxidant?
Zinc plays a major role in cell-mediated immunity in humans, and is also an antioxidant and anti-inflammatory agent. Studies of zinc supplementation in elderly people have shown decreased infection incidence, decreased oxidative stress and decreased inflammatory cytokine production.
Which fruit is high in antioxidants?
Most fruits are rich in antioxidants, filled with vitamins, and have a variety of benefits. These include cranberries, red grapes, peaches, raisins, strawberries, red currants, figs, cherries, pears, guava, oranges, apricots, mango, red grapes, cantaloupe, watermelon, papaya, and tomatoes.
Is coffee an antioxidant?
Coffee is a rich source of antioxidants which fight disease. And studies have shown it can minimize cavities, enhance athletic performance, improve moods, and avoid headaches not to mention lower the risk of type 2 diabetes, colon cancer, liver cancer, gallstones, liver cirrhosis, and Parkinson’s disease.
What are the main antioxidants?
Vitamins C and E, selenium, and carotenoids such as beta-carotene, lycopene, lutein, and zeaxanthin are examples of antioxidants. This fact sheet offers basic antioxidant statistics, summarizes what research is saying about antioxidants and safety, and recommends sources for further details.