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Lipid peroxidation, or lipid oxidation, is a complex chemical process that leads to oxidative degradation of lipids, [1] resulting in the formation of peroxide and hydroperoxide derivatives. [2] It occurs when free radicals , specifically reactive oxygen species (ROS), interact with lipids within cell membranes , typically polyunsaturated fatty ...
Many common phenomena can be attributed to autoxidation, such as food going rancid, [2] the 'drying' of varnishes and paints, and the perishing of rubber. [3] It is also an important concept in both industrial chemistry and biology. [4] Autoxidation is therefore a fairly broad term and can encompass examples of photooxygenation and catalytic ...
Alpha-tocopherol is a fat-soluble antioxidant functioning within the glutathione peroxidase pathway, [15] and protecting cell membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. [3] [16] This removes the free radical intermediates and prevents the oxidation reaction from continuing.
It has been claimed [by whom?] that the α-tocopherol form is the most important lipid-soluble antioxidant, and that it protects membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. [82] [85] This removes the free radical intermediates and prevents the propagation reaction from continuing.
Oxidative stress mechanisms in tissue injury. Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination).. Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. [1]
The termination phase involves the interaction of a radical with an antioxidant molecule, such as α-tocopherol (vitamin E), which inhibits the propagation of chain reactions, thus terminating peroxidation. Another method of termination is the reaction between a lipid radical and a lipid peroxide, or the combination of two lipid peroxide ...
The natural antioxidants tend to be short-lived, [13] so synthetic antioxidants are used when a longer shelf-life is preferred. The effectiveness of water-soluble antioxidants is limited in preventing direct oxidation within fats, but is valuable in intercepting free radicals that travel through the aqueous parts of foods.
This is a list of antioxidants naturally occurring in food. Vitamin C and vitamin E – which are ubiquitous among raw plant foods – are confirmed as dietary antioxidants, whereas vitamin A becomes an antioxidant following metabolism of provitamin A beta-carotene and cryptoxanthin.