title: A new extraction approach to correct the effect of apparent increase in the secoiridoid content after filtration of virgin olive oil.
abstract: In the current study, a new approach has been developed for correcting the effect that moisture reduction after virgin olive oil (VOO) filtration exerts on the apparent increase of the secoiridoid content by using an internal standard during extraction. Firstly, two main Spanish varieties (Picual and Hojiblanca) were submitted to industrial filtration of VOOs. Afterwards, the moisture content was determined in unfiltered and filtered VOOs, and liquid-liquid extraction of phenolic compounds was performed using different internal standards. The resulting extracts were analyzed by HPLC-ESI-TOF/MS, in order to gain maximum information concerning the phenolic profiles of the samples under study. The reduction effect of filtration on the moisture content, phenolic alcohols, and flavones was confirmed at the industrial scale. Oleuropein was chosen as internal standard and, for the first time, the apparent increase of secoiridoids in filtered VOO was corrected, using a correction coefficient (Cc) calculated from the variation of internal standard area in filtered and unfiltered VOO during extraction. This approach gave the real concentration of secoiridoids in filtered VOO, and clarified the effect of the filtration step on the phenolic fraction. This finding is of great importance for future studies that seek to quantify phenolic compounds in VOOs.
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Fuentenueva s/n, E- 18071 Granada, Spain; Functional Food Research and Development Center, Health Science Technological Park, Avenida del Conocimiento s/n, E-18016 Granada, Spain.
authors.forename: Abdelhakim
authors.initials: A
authors.lastname: Bakhouche
authors.affiliation: Functional Food Research and Development Center, Health Science Technological Park, Avenida del Conocimiento s/n, E-18016 Granada, Spain; Research and Development of Functional Olive Oil Department, Aceites Maeva S. L. Avda. Incar, S/N 18130 Escúzar Granada, Spain. Electronic address: jesusls@ugr.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Lozano-Sánchez
authors.affiliation: Department of Food Science, Faculty of Food Engineering, University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, 13083-862, Campinas, SP, Brazil.
authors.forename: Cristiano Augusto
authors.initials: CA
authors.lastname: Ballus
authors.affiliation: Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, piazza Goidanich, 60, I-47521 Cesena (FC), Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bendini
authors.affiliation: Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, piazza Goidanich, 60, I-47521 Cesena (FC), Italy.
authors.forename: Tullia
authors.initials: T
authors.lastname: Gallina-Toschi
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Fuentenueva s/n, E- 18071 Granada, Spain; Functional Food Research and Development Center, Health Science Technological Park, Avenida del Conocimiento s/n, E-18016 Granada, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernández-Gutiérrez
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Fuentenueva s/n, E- 18071 Granada, Spain; Functional Food Research and Development Center, Health Science Technological Park, Avenida del Conocimiento s/n, E-18016 Granada, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Segura-Carretero
keywords: Filtration; HPLC-ESI-TOF/MS; Internal standard; Moisture; Phenolic compounds; VOO