Abstract: This bioactivity capacity of vegetable tannins, including free radical scavenging activity and protein precipitation capacity are generally recognized to be largely dependent on their structure and particularly molecular weight (degree of polymerization). So the study on structure analysis of vegetable tannins has been paid much attention in recent years. This review deals with the main issues related to the analysis of vegetable tannins in the last 10 years. Thin layer chromatography (TLC) and high performance liquid chromatograph (HPLC) are useful tools to screen samples for the different types of tannins. Nuclear magnetic resonance (NMR) and mass spectrometry (MS) are used to identify pure tannin compounds. More recently, MALDI-TOF MS techniques have been developed, which are capable of yielding molecular weights of crude tannin mixtures. MALDI-TOF MS has proved to be highly suitable for the analysis of highly polydisperse and heterogeneous proanthocyanidins.

Key words: vegetable tannins, chemical structure, analytical methods, MALDI-TOF MS