Collagen films with improved wet state mechanical properties by mineralization

Authors: LIU, FEI - Jiangnan University; ZHU, KAIDI - Jiangnan University; MA, YUXIN - Jiangnan University; YU, ZHE - Jiangnan University; Chiou, Bor-Sen; JIA, MENGWEI - Jiangnan University; CHEN, MAOSHEN - Jiangnan University; ZHONG, FANG - Jiangnan University

Submitted to: Food Hydrocolloids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2023
Publication Date: 2/13/2023
Citation: Liu, F., Zhu, K., Ma, Y., Yu, Z., Chiou, B., Jia, M., Chen, M., Zhong, F. 2023. Collagen films with improved wet state mechanical properties by mineralization. Food Hydrocolloids. 139. Article 108579. https://doi.org/10.1016/j.foodhyd.2023.108579.
DOI: https://doi.org/10.1016/j.foodhyd.2023.108579

Interpretive Summary: Collagen films have been widely used as casings for sausages. However, their mechanical and water resistance properties need to be improved for wider use as packaging materials. In this study, we used two techniques to incorporate minerals into collagen films to improve their properties. The first technique involved soaking the films in calcium phosphate nanoparticles blended with carboxymethyl chitosan. The second technique involved sequential dipping of films in calcium chloride and disodium phosphate. The films produced using the first technique had stronger mechanical properties and lower heat shrinkage compared to the films without mineral incorporation and those prepared using the second technique. This was due to the films containing the nanoparticle/chitosan blend (first technique) showing intact collagen structures, whereas the the films from sequential dipping (second technique) had damaged collagen structures. These results indicated that incorporating mineral nanoparticles can be used to improve the properties of collagen films for packaging applications.

Technical Abstract: Collagen films have weak mechanical properties and poor water resistance. Herein, two mineralization processes were designed to improve the mechanical properties of collagen fibers under wet conditions for use as packaging materials. One scheme (S1) involved preparing carboxymethyl chitosan amorphous calcium orthophosphate (CMCS-ACP) nanoparticles, dispersing them in an aqueous solution and then immersing the collagen film in the dispersion to introduce the inorganic phase. Another scheme (S2) introduced the inorganic phase by alternately soaking in a CaCl2 and a Na2HPO4 solution. S1 introduced an amorphous inorganic phase and enhanced the wet tensile strength of collagen films. S2 introduced a large number of inorganic phases, but did not significantly enhance the wet tensile strength of the film. The amorphous inorganic phase from S1 did not destroy the triple helix structure of the collagen film, whereas the direct calcium phosphate deposition from S2 greatly damaged the original structure of the collagen membrane, resulting in poorer mechanical properties.