DMACA assay

The following functional group assays are used proanthocyanidin assay, vanillin assay and dimethylaminocinnamaldehyde (DMACA) assay. Details to the experimental designs are listed in Tab. (3.1) to (3.3). 

Catechin is generally used as a standard in the DMACA assay. Calibration plots are linear and therefore, calibration factors are also applied [148]. Like in all conventional methods the use of purified procyanidins as a standard will give the correctest estimates. A blank, composed of the samples without the chromogen reagent, is also... 

DMCA assay is used to quantify catechins, and it is based on the formation of a green chromophore between catechin and 4-(dimethylamino)-cinnamaldehyde (DMACA) (Polster and others 2003). 

Unfortunately, there exist a variety of different protocols. None of these protocols is generally accepted as an universal method. The assay of Delcour and Janssens de Varebeke [148] has been adopted by the European Brewery Convention Analysis Committee as an official method, but a new protocol has recently been published for the analysis of beer [31]. To our knowledge, one of the most carefully optimized DMACA protocols at this time is the one of Li et al. [67] for the analysis of forage legumes. 

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