Analysis of Proanthocyanidins in Food Ingredients by the 4‐(Dimethylamino)cinnamaldehyde Reaction

Proanthocyanidins (PACs) are oligomeric flavan-3-ols found in fruits and botanicals that are used as ingredients in dietary supplements due to their putative health benefits. In the United States, consumers spend over $9.6 billion on dietary supplements annually. PAC-containing dietary supplements lack standardization, may not be authentic and lack research on efficacy. The 4-(dimethylamino)cinnamaldehyde (DMAC) method for quantifying PACs, is preferred over the vanillin-HCl and butanol-HCl due to greater sensitivity, repeatability, and precision. However, the DMAC method has several problems related to accuracy. In this chapter, we discuss our research on the DMAC reaction with PACs in order to illustrate the importance of the choice of standards. We also discuss the DMAC reaction mechanism in relation to the absorbance and fluorescent spectra of the reaction products.