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Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time
Published on: October 26, 2016
The effect of solvent composition on grafting gallic acid onto chitosan via carbodiimide
Ping Guo1, John D Anderson2, Joseph J Bozell2
1Department of Food Science and Technology, University of Tennessee, 2510 River Drive, Knoxville, TN 37996, United States.
Abstract:
The primary antioxidant (AOX) activity of chitosan can be introduced by grafting of phenolic compound - gallic acid (GA) to its amino and/or hydroxyl groups. The objective of this study was to investigate the effect of ethanol (EtOH) concentration (0%, 25%, 50%, and 75% in water) on efficiency of grafting GA onto chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS). The grafting was confirmed by FTIR and the efficiency was quantified as Folin's total phenolics. When pure deionized water was used as a sole solvent (0% EtOH), GA was grafted to chitosan at the largest extent (285.9mg GA/g chitosan). As the concentration of EtOH increased, the grafting efficiency proportionally decreased. NMR studies showed that EtOH inhibited grafting of GA by prohibiting the production of the intermediate - NHS ester. The results confirm that the concentration of EtOH in grafting solution significantly affects grafting efficiency of GA on chitosan.
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