title: Effect of pressurized hot water extraction on antioxidants from grape pomace before and after enological fermentation.
abstract: Grape pomace was extracted with pressurized hot water at laboratory scale before and after fermentation to explore the effects of fermentation and extraction temperature (50-200 °C) and time (5 and 30 min) on total extracted antioxidant levels and activity and to determine the content and recovery efficiency of main grape polyphenols, anthocyanins, and tannins. Fermented pomace yielded more total antioxidants (TAs), antioxidant activity, and tannins, than unfermented pomace but fewer anthocyanins. Elevating the extraction temperature increased TA extraction and antioxidant activity. Maximum anthocyanin extraction yields were achieved at 100 °C and at 150 °C for tannins and tannin-anthocyanin adducts. Using higher temperatures and longer extraction times resulted in a sharp decrease of polyphenol extraction yield. Relevant proanthocyanidin amounts were extracted only at 50 and 100 °C. Finally, TA recovery and activity were not directly related to the main polyphenol content when performing pressurized hot water grape pomace extraction.
authors.affiliation: Pontificia Universidad Católica de Chile, Department of Chemical and Bioprocesses Engineering, Santiago, Chile.
authors.forename: José R
authors.initials: JR
authors.lastname: Vergara-Salinas
authors.forename: Pedro
authors.initials: P
authors.lastname: Bulnes
authors.forename: María Carolina
authors.initials: MC
authors.lastname: Zúñiga
authors.forename: Jara
authors.initials: J
authors.lastname: Pérez-Jiménez
authors.forename: Josep Lluís
authors.initials: JL
authors.lastname: Torres
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Mateos-Martín
authors.forename: Eduardo
authors.initials: E
authors.lastname: Agosin
authors.forename: José R
authors.initials: JR
authors.lastname: Pérez-Correa
mesh_terms: D000872:Anthocyanins / Q000032:analysis; D000975:Antioxidants / Q000032:analysis*; D005285:Fermentation; D005511:Food Handling / Q000379:methods*; D005638:Fruit / Q000737:chemistry; D006358:Hot Temperature; D010936:Plant Extracts / Q000737:chemistry*; D059808:Polyphenols / Q000032:analysis; D011312:Pressure; D044945:Proanthocyanidins / Q000032:analysis; D013634:Tannins / Q000032:analysis; D013997:Time Factors; D027843:Vitis / Q000737:chemistry*; D014920:Wine / Q000032:analysis*
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D010936:Plant Extracts; D059808:Polyphenols; D044945:Proanthocyanidins; D013634:Tannins