title: Molar absorptivity (ε) and spectral characteristics of cyanidin-based anthocyanins from red cabbage.
abstract: Red cabbage extract contains mono and di-acylated cyanidin (Cy) anthocyanins and is often used as food colorants. Our objectives were to determine the molar absorptivity (ε) of different red cabbage Cy-derivatives and to evaluate their spectral behaviors in acidified methanol (MeOH) and buffers pH 1-9. Major red cabbage anthocyanins were isolated using a semi-preparatory HPLC, dried and weighed. Pigments were dissolved in MeOH and diluted with either MeOH (0.1% HCl) or buffers to obtain final concentrations between 5×10(-5) and 1×10(-3) mol/L. Spectra were recorded and ε calculated using Lambert-Beer's law. The ε in acidified MeOH and buffer pH 1 ranged between ~16,000-30,000 and ~13,000-26,000 L/mol cm, respectively. Most pigments showed higher ε in pH 8 than pH 2, and lowest ε between pH 4 and 6. There were bathochromic shifts (81-105 nm) from pH 1 to 8 and hypsochromic shifts from pH 8 to 9 (2-19 nm). Anthocyanins molecular structures and the media were important variables which greatly influenced their ε and spectral behaviors.
authors.affiliation: Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Road, Columbus, OH 43210, USA.
authors.forename: Neda
authors.initials: N
authors.lastname: Ahmadiani
authors.affiliation: Science and Discovery Group, Mars Inc., 800 High Street, Hackettstown, NJ 07840, USA.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Robbins
authors.affiliation: Science and Discovery Group, Mars Inc., 800 High Street, Hackettstown, NJ 07840, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Collins
authors.affiliation: Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Road, Columbus, OH 43210, USA. Electronic address: giusti.6@osu.edu.
authors.forename: M Monica
authors.initials: MM
authors.lastname: Giusti
mesh_terms: D000215:Acylation; D000872:Anthocyanins / Q000032:analysis*; D001937:Brassica / Q000737:chemistry*; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005505:Food Coloring Agents; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D010860:Pigments, Biological / Q000032:analysis*; D010936:Plant Extracts / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D002021:Buffers; D005505:Food Coloring Agents; D010860:Pigments, Biological; D010936:Plant Extracts; C017154:cyanidin
keywords: Cyanidin derivatives; Molar absorptivity (ε); Red cabbage; Spectral characteristics