IntroductionAntioxidant is a molecule presence in natural and synthetic way, that prevent consuming product (cosmetics, medicine, food, oil) from the invasion of auto-oxidation. The optimal concentration of antioxidant is essential for increase the oxidative stability of food product from the free-radicals attack and other effect that decrease shelf life product:AH2 + HROO• ? •AH + HROOHScavenge free radical by donating hydrogen through antioxidant and produce stable free-radical antioxidant with reduction potential (<500mV) (Choe and Min, 2009). The assigned properties of stable free radical antioxidant (•AH) that is: (i) it should not react with Oxygen (O2), (ii) So, it should not initiate propagation reaction of oxidation. Evanesced the free-radical antioxidant (•AH) reaction with each other (Simic 1981). In the autoxidation, intermediate conversion of lipid that subsequently converted to derived lipid (it's called rancidity) that provide off-flavour and enhanced the oxidation process. Three stages of autoxidation that explained degradation of oil:-Initiation:- Free radical react with O2 (K=109 l mol-1 s-1), and peroxy radical formed that invasion on other several lipid or remove hydrogen (H) that created hydroperoxide (intermediate condition) and another free radical produced:-RH + O2 ? R• + RO2• + OH• + H2O Hydroperoxides (ROOH) thermal dissociationROOH ? RO• + OH• Hydroperoxides of Metal catalysed decompositionROOH + M2+ ? RO• + OH• + M3+ROOH + M3+ ? ROO• + H+ + M2+Photo-oxidation catalysed by exposure of lightPropagation:- Two free radical (alkoxide and hydroxyl) formed by break of hydroperoxides or it provide peroxy radical, hydroxyl free radical and water. And free radical proliferation (branching steps) that encored propagation (it's called autocatalytic reaction) it is :- R• + O2 ? RO2•RO2• + RH ? ROOH + R•Branching:-ROOH ? RO• +OH•2ROOH ? ROO• + RO• +H2OTermination-: The interaction between two free radical species and produced non-radical species, it occured when then colliding of two high potential radical at the substantial concentration of radical species (Hamilton et al.
1997 and Pullen and Saeed 2012).Terminated at low oxygen environment2R• ? R• RTerminated at high oxygen environmentR• + RO2• ? ROOHRO2• + RO2• ? ROOH + O2 In the food oil antioxidant act as pro-oxidant that increase oxidation with the help of higher dose and presence of metal ions. The oxidized antioxidant ( act as pro-oxidant) contain polar hydroxyl and non-polar hydrocarbons. The pro-oxidant effect on the oxidized antioxidant was different depending on the type of oil. In various component systems, some antioxidants can energize each other by ancillary effects known as synergism (Frankel, 1998) it prevent lipids from degradation.
In this review provide information of antioxidants effect on different oils, pro-oxidant effect of antioxidant by different concentration, synergistic effect of antioxidant, interaction of antioxidant with auto-oxidation.