title: Enzyme-assisted extraction enhancing the phenolic release from cauliflower (Brassica oleracea L. var. botrytis) outer leaves.
abstract: Phenolic compounds are highly present in byproducts from the cauliflower (Brassica oleracea L. var. botrytis) harvest and are thus a valuable source for valorization toward phenolic-rich extracts. In this study, we aimed to optimize and characterize the release of individual phenolic compounds from outer leaves of cauliflower, using two commercially available polysaccharide-degrading enzymes, Viscozyme L and Rapidase. As major results, the optimal conditions for the enzyme treatment were: enzyme/substrate ratio of 0.2% for Viscozyme L and 0.5% for Rapidase, temperature 35 °C, and pH 4.0. Using a UPLC-HD-TOF-MS setup, the main phenolic compounds in the extracts were identified as kaempferol glycosides and their combinations with different hydroxycinnamic acids. The most abundant components were kaempferol-3-feruloyldiglucoside and kaempferol-3-glucoside (respectively, 37.8 and 58.4 mg rutin equiv/100 g dry weight). Incubation of the cauliflower outer leaves with the enzyme mixtures resulted in a significantly higher extraction yield of kaempferol-glucosides as compared to the control treatment.
authors.affiliation: Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, and ‡Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University , Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Nguyen Thai
authors.initials: NT
authors.lastname: Huynh
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
authors.forename: Gerard Bryan
authors.initials: GB
authors.lastname: Gonzales
authors.forename: John
authors.initials: J
authors.lastname: Van Camp
authors.forename: Katleen
authors.initials: K
authors.lastname: Raes
mesh_terms: D001937:Brassica / Q000737:chemistry*; D003373:Coumaric Acids / Q000032:analysis; D044949:Kaempferols / Q000032:analysis; D010636:Phenols / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D003373:Coumaric Acids; D044949:Kaempferols; D010636:Phenols; C006552:kaempferol