title: Assessment of total (free and bound) phenolic compounds in spent coffee extracts.
abstract: Spent coffee is the main byproduct of the brewing process and a potential source of bioactive compounds, mainly phenolic acids easily extracted with water. Free and bound caffeoylquinic (3-CQA, 4-CQA, 5-CQA), dicaffeoylquinic (3,4-diCQA, 3,5-diCQA, 4,5-diCQA), caffeic, ferulic, p-coumaric, sinapic, and 4-hydroxybenzoic acids were measured by HPLC, after the application of three treatments (alkaline, acid, saline) to spent coffee extracts. Around 2-fold higher content of total phenolics has been estimated in comparison to free compounds. Phenolic compounds with one or more caffeic acid molecules were approximately 54% linked to macromolecules such as melanoidins, mainly by noncovalent interactions (up to 81% of bound phenolic compounds). The rest of the quantitated phenolic acids were mainly attached to other structures by covalent bonds (62-97% of total bound compounds). Alkaline hydrolysis and saline treatment were suitable to estimate total bound and ionically bound phenolic acids, respectively, whereas acid hydrolysis is an inadequate method to quantitate coffee phenolic acids.
authors.affiliation: †Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, IdiSNA, Navarra Institute for Health Research, E-31008 Pamplona, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Monente
authors.affiliation: †Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, IdiSNA, Navarra Institute for Health Research, E-31008 Pamplona, Spain.
authors.forename: Iziar A
authors.initials: IA
authors.lastname: Ludwig
authors.affiliation: ‡Department of Organic and Pharmaceutical Chemistry, School of Pharmacy, C.I.F.A., University of Navarra, E-31008 Pamplona, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Irigoyen
authors.affiliation: †Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, IdiSNA, Navarra Institute for Health Research, E-31008 Pamplona, Spain.
authors.forename: María-Paz
authors.initials: MP
authors.lastname: De Peña
authors.affiliation: †Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, IdiSNA, Navarra Institute for Health Research, E-31008 Pamplona, Spain.
authors.forename: Concepción
authors.initials: C
authors.lastname: Cid
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification; D002109:Caffeic Acids / Q000737:chemistry / Q000302:isolation & purification; D002726:Chlorogenic Acid / Q000737:chemistry / Q000302:isolation & purification; D040503:Coffea / Q000737:chemistry*; D062385:Hydroxybenzoates / Q000737:chemistry / Q000302:isolation & purification; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D012639:Seeds / Q000737:chemistry*; D014866:Waste Products / Q000032:analysis*
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D062385:Hydroxybenzoates; D010636:Phenols; D010936:Plant Extracts; D014866:Waste Products; D002726:Chlorogenic Acid; C017616:phenolic acid; C040048:caffeic acid
keywords: byproducts; coffee; hydrolysis; melanoidins; phenolics