title: Removal of 4-Ethylphenol and 4-Ethylguaiacol with Polyaniline-Based Compounds in Wine-Like Model Solutions and Red Wine.
abstract: Volatile phenols, such as 4-ethyphenol (4-EP) and 4-ethylguaiacol (4-EG), are responsible for the "Brett character" found in wines contaminated with Brettanomyces yeast (i.e., barnyard, animal, spicy and smoky aromas). In these trials, we explore the effectiveness of polyaniline-based compounds (polyaniline emeraldin salt (PANI-ES) and polyanaline emeraldin base (PANI-EB)), for the removal of 4-EP and 4-EG from acidic model solutions and red wine. First, a screening study, performed in an acidified 12% ethanol solution, was used to optimize parameters such as contact time and the amount of polymers required to remove 4-EP and 4-EG. Then, the trapping ability of PANI agents towards 4-EP and 4-EG was evaluated in a model solution containing other wine phenolics that could potentially be trapped by PANI (i.e., gallic acid and 4-methylcatechol). The results of this trial showed that both PANI compounds were capable of removing 4-EP, 4-EG, regardless of the presence of other phenolic compounds present at a much higher concentration. Finally, the capturing ability of PANI was evaluated in a red wine sample containing 5 mg·L-1 of 4-EP, 5 mg·L-1 of 4-EG and 2.03 ± 0.02 g·L-1 of total phenolics. The results showed that PANI-EB removed significantly more 4-EP and 4-EG than PANI-ES. For instance, a treatment with 10 mg·mL-1 of PANI-EB produced a 67.8% reduction of 4-EP, 50% reduction of 4-EG and 41.38% decrease in total phenols.
authors.affiliation: School of Agricultural Sciences, Universidad de Talca, Talca 3460000, Chile. vecarrasco@utalca.cl.
authors.forename: Verónica
authors.initials: V
authors.lastname: Carrasco-Sánchez
authors.affiliation: Laboratory of Asymmetric Synthesis, Chemistry Institute of Natural Resources, Universidad de Talca, Talca 3460000, Chile. johnamalraj@gmail.com.
authors.forename: Amalraj
authors.initials: A
authors.lastname: John
authors.affiliation: Laboratory of Asymmetric Synthesis, Chemistry Institute of Natural Resources, Universidad de Talca, Talca 3460000, Chile. amarican@utalca.cl.|Nanobiotechnology Division at Universidad de Talca, Fraunhofer Chile Research Foundation-Center for Systems Biotechnology, FCR-CSB, Talca 3460000, Chile. amarican@utalca.cl.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Marican
authors.affiliation: Laboratory of Asymmetric Synthesis, Chemistry Institute of Natural Resources, Universidad de Talca, Talca 3460000, Chile. lssantos@utalca.cl.|Nanobiotechnology Division at Universidad de Talca, Fraunhofer Chile Research Foundation-Center for Systems Biotechnology, FCR-CSB, Talca 3460000, Chile. lssantos@utalca.cl.
authors.forename: Leonardo S
authors.initials: LS
authors.lastname: Santos
authors.affiliation: School of Agricultural Sciences, Universidad de Talca, Talca 3460000, Chile. flaurie@utalca.cl.|Nanobiotechnology Division at Universidad de Talca, Fraunhofer Chile Research Foundation-Center for Systems Biotechnology, FCR-CSB, Talca 3460000, Chile. flaurie@utalca.cl.
authors.forename: V Felipe
authors.initials: VF
authors.lastname: Laurie
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D002396:Catechols / Q000032:analysis; D005707:Gallic Acid / Q000032:analysis; D006139:Guaiacol / Q000031:analogs & derivatives* / Q000302:isolation & purification; D010636:Phenols / Q000302:isolation & purification*; D012015:Reference Standards; D012996:Solutions; D014920:Wine / Q000032:analysis*
chemical_list: D000814:Aniline Compounds; D002396:Catechols; D010636:Phenols; D012996:Solutions; C416807:polyaniline; C018599:4-methylcatechol; D005707:Gallic Acid; D006139:Guaiacol; C042291:4-ethylphenol; C084991:4-ethylguaiacol
keywords: 4-EG; 4-EP; QuEChERS; conjugated polymers; polyaniline; wine