Chemical Modification of Gelatin by a Natural Phenolic Cross-linker, Tannic Acid

• Published in: Journal of agricultural and food chemistry Vol. 58; no. 11; pp. 6809 - 6815
• Main Authors: Zhang, Xiaoqing, Do, My Dieu, Casey, Philip, Sulistio, Adrian, Qiao, Greg G, Lundin, Leif, Lillford, Peter, Kosaraju, Shantha
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.06.2010
• Subjects: Biological and medical sciences; Chemical Changes Induced by Processing/Storage; Chemical Phenomena; chemical reactions; chemical structure; Cross-Linking Reagents - chemistry; crosslinking; Food industries; food matrix; food processing; food processing quality; Fundamental and applied biological sciences. Psychology; gelatin; Gelatin - chemistry; Hydrogen Bonding; Hydrogen-Ion Concentration; hydrophobicity; mechanical properties; molecular weight; Phenol - chemistry; physicochemical properties; protein structure; swelling (materials); tannins; Tannins - chemistry; thermal stability; tannic acid; natural phenolic cross-linking; Gelatin; mechanical properties; Chemical modification; Phenolic acid; Phenols; Mechanical properties; Natural
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf1004226

Chemical modification of gelatin by a natural phenolic compound tannic acid (TA) at pH 8 was studied, and the properties of the modified gelatin materials were examined. The cross-linking effect was predominant when the TA content was lower, resulting in the formation of a partially insoluble cross-link network. The cross-linking structure was stable even under boiling, and the protein matrix became rigid, whereas the mechanical properties were enhanced. An effective cross-linking effect on gelatin matrix was achieved when the amount of TA was around 3 wt %. Further increase in the TA content enhanced the grafting and branching reactions between gelatin and TA in conjunction with the hydrogen bonding between gelatin and TA molecules. These effects produced an increase in molecular mobility of gelatin matrix, and the materials displayed a behavior similar to that of plasticized protein materials.