Determination of the antioxidant capacity of “Pistache amargo” using a biosensor based on Laccase Trametes Versicolor J. Juárez-Gómez a , M. T. Ramírez-Silva a , M. Palomar-Pardavé b , M. Romero-Romo b , P. Salinas-Hernádez c and F. Morales-Anzures c a Departamento de Química, Área de Química Analítica, Universidad Autónoma Metropolitana-Iztapalapa, México DF. México. b Departamento de Materiales, Área Ingeniería de Materiales, Universidad Autónoma Metropolitana-Azcapotzalco, México DF. México. c Departamento de Ingeniería Química, Universidad del Itsmo campus Tehuantepec, Oaxaca, México. In the region of the Itsmo of Tehuantepec, Oaxaca, México grows a variety of Pistache of the Anacardiaceae family. The fruit is composed of about 68% oil by weight and is rich in polyphenolic compounds. These are antioxidant molecules of great interest today for their beneficial effects to human health, and there is a strong interest in finding natural sources of antioxidants. For this reason, the present work shows the spectrophotometric studies using the DPPH radical method for the determination of the antioxidant capacity equivalent to caffeic acid in different extracts of the "Pistache Amargo" residual pulp. The spectrophotometric method is contrasted with an electrochemical method using a biosensor based on the enzyme Laccase Trameters Versicolor immobilized on a polyvinyl alcohol polymeric membrane. Introduction Presently there is a great interest in the experimental capacity to estimate the efficiency of diverse sustances acting as antioxydants; therefore, several methods have been developed to evaluate this property, which have been employed to assess their antioxydant activity when present in foodstuffs. Such methods depend on the specificity of the free radicals used as reactants that are limited to soluble compounds in a chosen solvent. The antioxydant compounds can be soluble in water or in lipids, insoluble or be adsorbed on cellular walls; hence they are not necessarily availables to react with the free radicals. That’s why they react in different percents and with varied kinetics. The phenolic and polyphenolic compounds comprise the main natural antioxydants class present in plants, foodstuffs and beverages that can be quantitavely determined using various methods. In general, the analytic methods mostly used for the determination of flavonoids are: UV, electrochemical, fluorescence and chemioluminiscence. Lately, enzyme-modified solid sensors have been used to determine simple phenols through amperometry. The lacasse enzyme catalyzes the oxidation of three isomers, 10.1149/06401.0077ecst ©The Electrochemical Society ECS Transactions, 64 (1) 77-81 (2014) 77 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 148.206.73.119 Downloaded on 2014-10-03 to IP