title: Effect of the drying process on the intensification of phenolic compounds recovery from grape pomace using accelerated solvent extraction.
abstract: In light of their environmental and economic interests, food byproducts have been increasingly exploited and valorized for their richness in dietary fibers and antioxidants. Phenolic compounds are antioxidant bioactive molecules highly present in grape byproducts. Herein, the accelerated solvent extraction (ASE) of phenolic compounds from wet and dried grape pomace, at 45 °C, was conducted and the highest phenolic compounds yield (PCY) for wet (16.2 g GAE/100 g DM) and dry (7.28 g GAE/100 g DM) grape pomace extracts were obtained with 70% ethanol/water solvent at 140 °C. The PCY obtained from wet pomace was up to two times better compared to the dry byproduct and up to 15 times better compared to the same food matrices treated with conventional methods. With regard to Resveratrol, the corresponding dry pomace extract had a better free radical scavenging activity (49.12%) than the wet extract (39.8%). The drying pretreatment process seems to ameliorate the antiradical activity, especially when the extraction by ASE is performed at temperatures above 100 °C. HPLC-DAD analysis showed that the diversity of the flavonoid and the non-flavonoid compounds found in the extracts was seriously affected by the extraction temperature and the pretreatment of the raw material. This diversity seems to play a key role in the scavenging activity demonstrated by the extracts. Our results emphasize on ASE usage as a promising method for the preparation of highly concentrated and bioactive phenolic extracts that could be used in several industrial applications.
authors.affiliation: Centre d'Analyses et de Recherche, UR TVA, Faculté des Sciences, Université Saint-Joseph, B.P. 11-514 Riad El Solh, Beirut 1107 2050, Lebanon. eugene.vorobiev@utc.fr.
authors.forename: Hiba N
authors.initials: HN
authors.lastname: Rajha
authors.affiliation: Institute of Chemistry, Karl-Franzens University of Graz, A-8010 Graz, Austria. walter.ziegler@uni-graz.at.
authors.forename: Walter
authors.initials: W
authors.lastname: Ziegler
authors.affiliation: Centre d'Analyses et de Recherche, UR TVA, Faculté des Sciences, Université Saint-Joseph, B.P. 11-514 Riad El Solh, Beirut 1107 2050, Lebanon. nicolas.louka@usj.edu.lb.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Louka
authors.affiliation: Centre d'Analyses et de Recherche, UR TVA, Faculté des Sciences, Université Saint-Joseph, B.P. 11-514 Riad El Solh, Beirut 1107 2050, Lebanon. zeina.hobaika@usj.edu.lb.
authors.forename: Zeina
authors.initials: Z
authors.lastname: Hobaika
authors.affiliation: UTC/ESCOM, EA 4297 TIMR, Département de Génie des Procédés Industriels, Laboratoire Transformations Intégrées de la Matière Renouvelable, Université de Technologie de Compiègne, Centre de Recherche de Royallieu, Compiègne Cedex, BP 20529 - 60205, France. eugene.vorobiev@utc.fr.
authors.forename: Eugene
authors.initials: E
authors.lastname: Vorobiev
authors.affiliation: Institute of Chemistry, Karl-Franzens University of Graz, A-8010 Graz, Austria. herbert.boechzelt@joanneum.at.
authors.forename: Herbert G
authors.initials: HG
authors.lastname: Boechzelt
authors.affiliation: Centre d'Analyses et de Recherche, UR TVA, Faculté des Sciences, Université Saint-Joseph, B.P. 11-514 Riad El Solh, Beirut 1107 2050, Lebanon. richard.maroun@usj.edu.lb.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Maroun
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000302:isolation & purification*; D003890:Desiccation; D005419:Flavonoids / Q000032:analysis / Q000302:isolation & purification; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification*; D010936:Plant Extracts / Q000032:analysis / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D027843:Vitis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D012997:Solvents