Effect of Gellan Gum with Different Acyl Contents on the Properties of Gelatin Films and a Novel Approach to Thermal Stability Assessment of Films

Abstract

Fish gelatin (FG) and gellan gum (GG) which have good biodegradability are widely used as the food packaging material. However, there was little research to explore the effects exerted by two varieties of GG, namely low acyl gellan gum (LAGG) and high acyl gellan gum (HAGG), on the properties of FG thin films. In this study, HAGG and LAGG, were mixed with FG for preparing the fish gelatin-gellan gum composite films (FG-GG films), respectively. The results showed that adding LAGG could improve the UV resistance of FG-GG films and provide good transparency. The films prepared by adding HAGG and FG had the highest tensile strength (5.72 MPa). The water vapor permeability of the films prepared by adding 0.08% HAGG was 0.339 g·mm/(m2·h·kPa), which was the lowest compared with the groups of adding LAGG. Meanwhile, an efficient and intuitive method proceeded by a combination of a constant temperature and humidity incubator and a Texture Analyzer to evaluate the thermal stability was established in this study. The results showed that adding 0.08% LAGG resulted in the highest thermal stability of the prepared FG-GG films. And the novel approach to the thermal stability assessment could be used for other thin films.

Keywords: Fish gelatin, gellan gum, films, thermal stability assessment.