Covalent and Ionic Bonding between Tannin and Collagen in Leather Making and Shrinking: A MALDI-ToF Study

Collagen powder hydrolysates were reacted with a solution of commercial mimosa bark tannin extract. The mixture was prepared at ambient temperature and 80°C to determine what reactions, if any, did occur between the collagen protein through its amino acids polyphenolic condensed tannin. reaction products obtained analyzed by matrix assisted laser desorption ionization time-of-flight (MALDI ToF) mass spectrometry. Reactions two materials appear occur, formation relatively small proportion covalent ionic linkages but considerable tannin-protein disappearance bonds. appeared be amination phenolic –OHs groups non-skeletal side chains arginine, esterification –COOH glutamic aspartic acid aliphatic alcohol-OH on C3 site flavonoid units heterocycle increases markedly predominate increasing temperatures. This tightening network formed may an additional contributing factor both leather wear resistance performance as well shrinking when this is subjected excessive