LITTLE ROCK, Ark.—A study published in the Journal of the Science of Food and Agriculture attempted to validate an improved 4-dimethylaminocinnamaldehyde (DMAC) colorimetric method to quantify proanthocyanidins (PACs) in cranberry powders, in order to establish dosage guidelines for the uropathogenic bacterial anti-adhesion effect of cranberry (published on line April 21, 2010). Commercially available cranberry samples were obtained for PAC quantification in five different analytical laboratories. For comparative purposes, the cranberry samples were alternatively quantified using weights of extracted PACs. The correlation coefficient between the two methods was 0.989.
Researchers concluded, “The improved DMAC method provided a simple, robust and relatively specific spectrophotometric assay for total PACs in cranberry samples using commercially available procyanidin A2 dimer as a standard. DMAC is most useful within a given type of food such as cranberries, but may not be appropriate for comparing concentrations across different food types, particularly in those cases where large differences exist among the relative amounts of each oligomer and polymer.”
