Skip to Main content Skip to Navigation
Journal articles

Multimethod Approach for Extensive Characterization of Gallnut Tannin Extracts

Abstract : Gallotannins extracted from gallnuts are commonly added to wine to improve its properties. They consist of mixtures of galloylester derivatives of glucose. However, their composition and properties are not well-established. In this study, methods based on liquid chromatography coupled to ultraviolet–visible detection and mass spectrometry, size-exclusion chromatography, and one-dimensional (31P) and two-dimensional (1H diffusion ordered spectroscopy, 31P total correlated spectroscopy, and 1H/13C heteronuclear single-quantum correlation and heteronuclear multiple-bond correlation) nuclear magnetic resonance spectroscopies have been implemented for extensive chemical characterization of three commercial gallnut tannin extracts. Differences in the proportions of the different constituents (gallic, digallic, and trigallic acids and galloylglucose derivatives) and in the structure and molecular weight distributions of gallotannins were demonstrated between the three extracts, with chains containing 8.5, 12.2, and 12.4 galloyl groups on average for TAN A, TAN B1, and TAN B2, respectively. The antioxidant capacities of the extracts, evaluated using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) method, were similar and related mostly to their total tannin content, with only a limited impact of the tannin composition.
Document type :
Journal articles
Complete list of metadata
Contributor : Céline Poncet-legrand Connect in order to contact the contributor
Submitted on : Friday, July 3, 2020 - 2:38:05 PM
Last modification on : Friday, May 20, 2022 - 9:04:08 AM



Aude Watrelot, Christine Le Guernevé, Hélène Hallé, Emmanuelle Meudec, Pascale Williams, et al.. Multimethod Approach for Extensive Characterization of Gallnut Tannin Extracts. Journal of Agricultural and Food Chemistry, American Chemical Society, In press, 68 (47), pp.13426-13438. ⟨10.1021/acs.jafc.9b08221⟩. ⟨hal-02888982⟩



Record views