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

Abstract

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.

Modification of collagen with a natural cross-linker, procyanidin

“…Further increasing the content of procyanidin (above 4%) leads WCA to decrease instead, as shown in the inset, which is likely due to the incomplete reactivity of excessive procyanidin in the films and the hydrophilic nature of procyanidin. Note that the WCA for the pure collagen film (≈92 • ) is about 10 • higher than the gelatin film in the literature [11], indicating the structural integrity of the collagen used in the present study. Fig.…”

“…Therefore, they are often modified for practical uses by various methods, such as UV-light irradiation, multivalent metal ions, and synthetic aldehyde-based cross-linkers [6,7]. However, the treatment by UV only modifies the surface instead of the bulk of the collagen [8], and the toxic nature of aldehyde compounds reflected in the process of manufacturing and application prohibits their utilization in food and biomaterials [9][10][11]. Thus, some natural polymers with favorable biocompatibility have been exploited as protein cross-linkers, such as genipin, oxidized alginate and dialdehyde starch [7,12,13].…”

Cutaneous biocompatible rutin-loaded gelatin-based nanoparticles increase the SPF of the association of UVA and UVB filters

“…More specifically, rutin incorporation into the networks can potentially alter the helical structure of gelatin and disrupt the hydrogen bonds. Chemical reactions are created between phenolic reactive sites and the amino groups in gelatin to form covalent bonds as the crosslinking linkages in gelatin (Peña et al, 2010;Zhang et al, 2010b).…”

The effects of sugars on moisture sorption isotherm and functional properties of cold water fish gelatin films

“…The skin, bone, cartilage, and tendon of animals such as cows, pigs, and fish are some of the sources of gelatin extraction [3,[7][8][9]. For reasons such as biodegradability, renewability [10,11], high productivity with low cost [12], and improvement of elasticity, consistency, and stability [9,13,14], gelatin has wide applications in the pharmaceutical and food industries [12].…”