title: Optimisation of antioxidant extraction from Solanum tuberosum potato peel waste by surface response methodology.
abstract: This study reports the optimised conditions (temperature, ethanol concentration and processing-time) for antioxidant extraction from potato peel (Agria variety) waste. At short extraction times (34 min), optimal yields of phenolic (TP) and flavonoid (Fv) compounds were reached at 89.9°C and ethanol concentrations of 71.2% and 38.6%, respectively. The main phenolic compounds identified in the extracts were chlorogenic (Cl) and ferulic (Fer) acids. A significant positive correlation was found between antioxidant activity and TP, Fv, Fer and Cl responses. Potato peel extracts were able to stabilize soybean oil under accelerated oxidation conditions, minimising peroxide, totox and p-anisidine indices. The production of hexanal and 2-hexenal in soybean oil samples was maximal for extracts obtained at intermediate temperatures and ethanol concentrations. Our results demonstrate potato peel waste is a good source of antioxidants able to effectively limit oil oxidation, while contributing to the revalorisation of these agrifood by-products.
authors.affiliation: Group of Recycling and Valorization of Waste Materials (REVAL), Marine Research Institute (IIM-CSIC), C/Eduardo Cabello, 6, Vigo 36208, Galicia, Spain.
authors.forename: Isabel Rodríguez
authors.initials: IR
authors.lastname: Amado
authors.affiliation: Meat Technology Center, C/Galicia 4, Parque Tecnolóxico de Galícia, San Cibrán das Viñas, Ourense 32900, Galicia, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Franco
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Campus Sur, Santiago de Compostela 15786, Galicia, Spain.
authors.forename: Marivel
authors.initials: M
authors.lastname: Sánchez
authors.affiliation: Department of Genetics, CIBUS Building, University of Santiago de Compostela, Campus Sur, Santiago de Compostela 15786, Galicia, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Zapata
authors.affiliation: Group of Recycling and Valorization of Waste Materials (REVAL), Marine Research Institute (IIM-CSIC), C/Eduardo Cabello, 6, Vigo 36208, Galicia, Spain. Electronic address: jvazquez@iim.csic.es.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Vázquez
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry*; D011198:Solanum tuberosum / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts
keywords: Antioxidant extraction; By-products upgrade; Potato peel waste; Process optimisation; Response surface methodology