title: Intermolecular binding of blueberry pectin-rich fractions and anthocyanin.
abstract: Pectin was extracted from blueberry powder into three fractions of water soluble (WSF), chelator soluble (CSF) and sodium carbonate soluble (NSF). The fractions were incubated with cyanidin-3-glucoside (C3G), a mixture of five anthocyanidins (cyanidin, pelargonidin, malvidin, petunidin and delphinidin) or blueberry juice at pH 2.0-4.5. Free anthocyanins and bound anthocyanin-pectin mixtures were separated by ultrafiltration. WSF bound the least amount of anthocyanin at all pH values. CSF had stronger anthocyanin binding ability at pH 2.0-3.6, while NSF had stronger anthocyanin binding ability at pH 3.6-4.5. The pectin and anthocyanin binding was lowest at pH 4.5 and higher at pH 2.0-3.6. Nearly doubling C3G pigment content increased bound anthocyanin percentage by 16-23% at pH 3.6, which favored anthocyanin aromatic stacking, compared to 3-9% increase at pH 2.0. Ionic interaction between anthocyanin flavylium cations and free pectic carboxyl groups, and anthocyanin stacking may be two major mechanisms for pectin and anthocyanin binding.
authors.affiliation: Department of Food Science, University Massachusetts, Amherst, MA, USA(1); University of Georgia, Department of Food Science and Technology, Athens, GA, USA(2).
authors.forename: Z
authors.initials: Z
authors.lastname: Lin
authors.affiliation: University of Georgia, Department of Foods and Nutrition, Athens, GA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Fischer
authors.affiliation: University of Georgia, Department of Food Science and Technology, Athens, GA, USA(2); Department of Home Economics Education, College of Education, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-701, Republic of Korea; School of Nutrition and Food Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, USA. Electronic address: lwicker@agcenter.lsu.edu.
authors.forename: L
authors.initials: L
authors.lastname: Wicker
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D029798:Blueberry Plants / Q000737:chemistry*; D005960:Glucosides / Q000737:chemistry*; D010368:Pectins / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D005960:Glucosides; C462279:cyanidin-3-O-beta-glucopyranoside; D010368:Pectins
keywords: Anthocyanin; Blueberry; Cyanidin-3-glucoside; Intermolecular binding; Pectin