title: Extraction of Honey Polyphenols: Method Development and Evidence of Cis Isomerization.
abstract: Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant's nectar, which are collected by bees, which convert the nectar into honey. Consequently, polyphenols constitute minor components of honey. The development of a solid-phase extraction method for honey polyphenols is presented in this study. The technique employs Amberlite XAD-2 adsorbent and was tested on monofloral honeys from six different plants: acacia, chestnut, eucalyptus, thyme, sunflower, and wild carrot. Analyses were performed using high-performance liquid chromatography coupled with UV detection and mass spectrometry. Several phenolic acids and flavonoids were identified: caffeic and p-coumaric acids, quercetin, kaempferol, naringenin, chrysin, and pinocembrin. Generally, the quantity of a given polyphenol in the honey was around 0.2 mg/100 g of honey, except for chestnut honey, which contained around 3.0 mg of p-coumaric acid/100 g of honey. Analyses highlighted significant formation of cis isomers for phenolic acids during the extraction despite protection from light.
authors.affiliation: Laboratory of Biological and Industrial Chemistry, University of Liege-Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Istasse
authors.affiliation: Laboratory of Biological and Industrial Chemistry, University of Liege-Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jacquet
authors.affiliation: Laboratory of Biological and Industrial Chemistry, University of Liege-Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berchem
authors.affiliation: Laboratory of Biological and Industrial Chemistry, University of Liege-Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Haubruge
authors.affiliation: Laboratory of Biological and Industrial Chemistry, University of Liege-Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Bach Kim
authors.initials: BK
authors.lastname: Nguyen
authors.affiliation: Laboratory of Biological and Industrial Chemistry, University of Liege-Gembloux Agro-Bio Tech, Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Aurore
authors.initials: A
authors.lastname: Richel
keywords: chromatography; honey; isomerization; polyphenols; solid-phase extraction