Determination of D-malic acid in apple juice by liquid chromatography: collaborative study

• Published in: Journal of AOAC International Vol. 79; no. 1; p. 50
• Main Author: Eisele, T.A. (Tree Top, Inc., Selah, WA.)
• Format: Journal Article
• Language: English
• Published: England 01.01.1996
• Subjects: ACIDE MALIQUE; ACIDO MALICO; ADULTERACION; ADULTERATION; ANALISIS CUANTITATIVO; ANALYSE QUANTITATIVE; Beverages - analysis; CALIDAD; CHROMATOGRAPHIE; Chromatography, High Pressure Liquid - methods; CROMATOGRAFIA; ESTRUCTURA QUIMICA; Food Additives - analysis; Fruit; JUS DE POMME; Malates - analysis; MEDICION; MESURE; QUALITE; Sensitivity and Specificity; Stereoisomerism; STRUCTURE CHIMIQUE; ZUMO DE MANZANA
• ISSN: 1060-3271; 1944-7922
• DOI: 10.1093/jaoac/79.1.50

Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of 16 mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collaborative study results demonstrated that the method could quantitate the economic adulteration of apple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice has been adopted first action by AOAC International