Premium
DETERMINATION OF VITAMIN C (L‐ASCORBIC ACID AND DEHYDROASCORBIC ACID) IN FOOD BY MANUAL AND AUTOMATED PHOTOMETRIC METHODS
Author(s) -
PELLETIER OMER,
BRASSARD RENE
Publication year - 1977
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1977.tb08402.x
Subject(s) - dehydroascorbic acid , ascorbic acid , fructose , chemistry , vitamin c , vitamin , sucrose , chromatography , food science , biochemistry
L‐ascorbic acid (AA) plus dehydroascorbic acid (DHAA) in foods were determined manually and with an automated sample processor according to the principles of the 2,4‐dinitrophenylhydrazine method of Pelletier [J. Lab. & Clin. Med. (1968), 72: 674] for biological materials but with modifications that rendered the methods simpler and applicable to foods. These methods eliminated interference from reductones (arising from sugars during food processing) and of diketogulonic acid (a product of the oxidation of DHAA). Sucrose in a concentration 30,000 times that of AA did not affect the vitamin C assay values. Fructose and glucose, in concentrations respectively 417 and 1668 times that of AA, increased the vitamin C values by only 2–3%. Since a higher range of concentrations of fructose and glucose together gave rather constant increase (8%) in vitamin C values, possible interference from the sugars in noncitrus fruits was eliminated by incorporating a mixture of these sugars in the solutions of standards and samples. Comparisons of vitamin C values in food between the proposed procedures and a modification of the widely used method of Roe [J. Biol. Chem. (1961b) 236: 1611] showed agreement (±5%) for 70% of the foods analyzed. Values were approximately 10% lower by the proposed procedures in the remaining samples. These differences were attributed to the greater specificity of the new methods. Precision of the new procedures was generally within a coefficient of variation of 6% and values (mean of 4 assays on different days) obtained with an automatic sample processor and with manual analyses agreed within 3%.