Analysis of commercial proanthocyanidins. Part 3: The chemical composition of wattle (Acacia mearnsii) bark extract

► Mass spectrometry investigation of the composition of wattle bark proanthocyanidins. ► Wattle bark proanthocyanidins consist predominantly of dimers and trimers. ► The starter units are angularly bonded catechin or gallocatechin. ► The extender units are the 5-deoxy flavan-3-ols, fisetinidol and robinetinidol. ► A rapid method to distinguish commercial quebracho and wattle tannin extracts.