title: Determination of total monomeric anthocyanin pigment content of fruit juices, beverages, natural colorants, and wines by the pH differential method: collaborative study.
abstract: This collaborative study was conducted to determine the total monomeric anthocyanin concentration by the pH differential method, which is a rapid and simple spectrophotometric method based on the anthocyanin structural transformation that occurs with a change in pH (colored at pH 1.0 and colorless at pH 4.5). Eleven collaborators representing commercial laboratories, academic institutions, and government laboratories participated. Seven Youden pair materials representing fruit juices, beverages, natural colorants, and wines were tested. The repeatability relative standard deviation (RSDr) varied from 1.06 to 4.16%. The reproducibility relative standard deviation (RSDR) ranged from 2.69 to 10.12%. The HorRat values were < or = 1.33 for all materials. The Study Director recommends that the method be adopted Official First Action.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Pacific West Area, Horticultural Crops Research Laboratory Worksite, 29603 University of Idaho Ln, Parma, ID 83660, USA. jlee@uidaho.edu
authors.forename: Jungmin
authors.initials: J
authors.lastname: Lee
authors.forename: Robert W
authors.initials: RW
authors.lastname: Durst
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Wrolstad
mesh_terms: D000872:Anthocyanins / Q000032:analysis* / Q000737:chemistry; D001628:Beverages / Q000032:analysis*; D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003299:Cooperative Behavior; D005505:Food Coloring Agents / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D005960:Glucosides / Q000032:analysis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012015:Reference Standards; D015203:Reproducibility of Results; D013696:Temperature; D014920:Wine / Q000032:analysis
chemical_list: D000872:Anthocyanins; D005505:Food Coloring Agents; D005960:Glucosides