Effects of physical crosslinking methods on digestibility in vitro and safety of edible packaging: A primary study on collagen films

Abstract

Crosslinking is often used to improve the mechanical strength and barrier properties of edible films. However, the effects on films’ digestibility and edible safety are still unknown. Herein, four crosslinking methods were utilized to crosslink collagen films, including UV irradiation, dehydrothermal treatment (DHT), tannin and glutaraldehyde. The crosslinked samples were then researched via in vitro digestion and cell culture model. With the INFOGEST method, the results of dry matter loss, degree of hydrolysis and absorbed collagen content have significantly correlated relations and showed excellent digestive ability of UV treated and DHT films. The results of the FTIR suggest that the crosslinking affects the structure of digestion and absorption. The toxicity and nutrition of the hydrolytes of collagen films were measured in Caco-2 and HepG-2 cells, and the collagen films, especially UV treated and tannin treated films, can promote cell growth while the glutaraldehyde treated one reduced cell viability presumably due to its residual in the films.