Comparative evaluation of the effect of antioxidants added into peanut (arachis hypogae l.) oil biodiesel by P-DSC and rancimat

Biodiesel, a blend of long-chain fatty acid alkyl esters, undergoes oxidation due to the degradation of unsaturated esters upon the contact with atmospheric oxygen or changes in temperature and moisture. In peanut biodiesel, oleate and linoleate represent more than 80 % of the overall ester content, which are the quality-determining esters. In the present work, oxidative stability of peanut oil biodiesel obtained by the methanolic and ethanolic routes was evaluated by P-DSC and Rancimat methods. The efficiency of different concentrations of antioxidant substances, alpha-tocopherol, TBHQ (tert-butylhydroquinone), and green tea extract (Camellia sinensis L.) added into biodiesel was investigated. The results showed that alpha-tocopherol acted as pro-oxidant in the two biodiesels, for all studied concentrations. The synthetic antioxidant substance, TBHQ, corrected the stability of biodiesels with high efficiency while green tea extract showed an antioxidant additive potential for use in biodiesel.