Assessment of the antioxidant effect of ethanol extract of Allium sativum L., isolated and/or synergistically associated with synthetic antioxidants, applied to linseed oil

The aim of this study was to assess the antioxidant power of ethanol extract of garlic (EEGL), isolated or associated with synthetic tert-butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT) antioxidants on the thermal and oxidative stability of linseed oil. The total phenolic content (Folin–Ciocalteu) of EEGL was preliminary determined as a procedure prior to additive supplementation of linseed oil. The EEGL effect, associated or not with TBHQ or BHT, on the oxidative stability of linseed oil was evaluated using the thermogravimetry, pressurized differential scanning calorimetry (PDSC), PetroOxy, and Rancimat. The results showed that EEGL, isolated or associated to synthetic antioxidants, conferred significant increase to the oxidative stability of linseed oil, offering resistance against primary oxidation, especially for samples LOGL 150, LOGL 100, and LOGL/TBHQ (50/50). Given the antioxidant potential and synergistic effect of garlic extract, when used in isolation or associated with TBHQ or BHT, it is feasible to use EEGL for the partial or total replacement of synthetic antioxidants by the edible oils industry.