New phenolic compounds hydrothermally extracted from the olive oil byproduct alperujo and their antioxidative activities

The application of a novel process based on the hydrothermal treatment of olive oil waste (alperujo) led to a final liquid phase that contained a high concentration of simple phenolic compounds. This study evaluated the effects of time (15-90 min) on the composition of the phenolic compounds isolated at a fixed temperature of 160 °C. Phenolic compounds were extracted with ethyl acetate. Both qualitative and quantitative HPLC analyses of the extracts showed variation of the concentrations of phenolic compounds with time. In addition, new phenols that were not present in the untreated control have been characterized. The antioxidant activities of different phenolic extracts was measured by various assays conducted in vitro: antiradical capacity (using DPPH and ABTS radicals), ferric reducing power (P R), inhibition of primary and secondary oxidation in lipid systems, and other tests, such as inhibition of tyrosinase activity. The results show that the phenolic extracts inhibited oxidation in aqueous and lipid systems to a significantly greater extent than the untreated control, and they performed as well as or better than vitamin E in this capacity. © 2012 American Chemical Society.F.R.-S. and G.R.-G. thank the Consejo Superior de Investigaciones Científicas (CSIC) of Spain for their research contracts (JAE Pre_2010_00425 and JAE Doc_2009_00666). This work was partially financed by Ministerio de Ciencia e Innovación of Spain (Grant AGL2009-12352) and Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía (Proyecto de Excelencia P08-AGR-03751).Peer Reviewe