Polymer structure of commercial hydrolyzable tannins by matrix‐assisted laser desorption/ionization‐time‐of‐flight mass spectrometry

Abstract

The structures of six commercial hydrolyzable tannins, chestnut, oak, tara, sumach, chinese gall, and turkey gall tannins have been examined by matrixassisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry. Their oligomeric structures and structure distributions have been defined. Degradation products of rather different structure than what previously reported were present. Different galloyl glucose monomers were observed for chestnut and oak tannin extracts and in chinese gall gallotannin extract. Combination of positive-and negative-mode MALDI-TOF showed that most galloyl residues of the galloyl glucose chains were stripped from a skeletal glucose chain. Oligomers, in some cases up to 16 or 17 glucose units long, almost totally stripped of galloyl residues were observed. This indicated that a wide distribution up to very long gaIloylglucose chains exist in most commercial hydrolyzable tannin extracts. This indicated that these commercial tannin extracts are mainly composed of long galloyl glucose chains of mixed di-, tri-, and pentagalloyl glucose repeating units being present in the same chain. The presence of long glucose chains where most of the galloyl residues have been stripped indicates that their linkage may be sugar residue to sugar residue. Commercial tara and turkey gall tannins have been shown to be mainly polygallic oligomers of up to eight gallic acid residues linked to each other in a chain. Commercial sumach extract revealed itself a more complex mixture of glucose oligomers up to 13 repeating units.

Synthesis, structure, and characterization of glyoxal‐urea‐formaldehyde cocondensed resins

“…In recent years, MALDI‐TOF‐MS has been widely used to analyze the structure of biological macromolecules and polymers owing to its advantages such as rapidity, accuracy, high sensitivity, high resolution, and wide mass range measurement capability. In comparison with the commonly used method of gel permeation chromatography, MALDI‐TOF‐MS can provide such information as polymers/oligomers molecular weight and their mass distribution range, copolymer composition, and to deduce the most probable reaction mechanism from the species obtained …”

“…In comparison with the commonly used method of gel permeation chromatography, MALDI-TOF-MS can provide such information as polymers/oligomers molecular weight and their mass distribution range, copolymer composition, and to deduce the most probable reaction mechanism from the species obtained. [51][52][53] To further study the molecular weight and oligomers distribution of the GUF resin and to deduce the reaction mechanism of MMU with G, the MALDI-TOF-MS spectra of the GUF resins with MMU/G molar ratio of 1.0 is shown in Figure 8.…”

Effects of chestnut tannins on intestinal morphology, barrier function, pro‐inflammatory cytokine expression, microflora and antioxidant capacity in heat‐stressed broilers

“…The hydrolysable tannin content was analysed with the rhodanine method and expressed as gallotannin equivalents (Makkar, ). Matrix‐assisted laser desorption/ionisation time of flight mass spectrometry (MALDI‐TOF MS) was used to characterise the structure of hydrolysable tannin (Pizzi, Pasch, Rode, & Giovando, ), and results showed that the CT contained (DM basis) 78 g/kg digalloyl glucose, 51 g/kg trigalloyl glucose, 164 g/kg pentagalloyl glucose and 707 g/kg oligomers of digalloyl glucose, trigalloyl glucose and pentagalloyl glucose.…”

Tannin Fingerprinting in Vegetable Tanned Leather by Solid State NMR Spectroscopy and Comparison with Leathers Tanned by Other Processes

“…Hydrolyzable tannins are complex mixtures of sugar monomers or polymers esterified with polyphenols such as gallic acid and its derivatives and closely related compounds [29][30][31]; typical constituent structures are exemplified in the figure.…”