Effects of two types of gellan gum on the properties of fish gelatin films and their application in fish meat preservation

Fish gelatin-gellan gum (FG-GG) composite films were prepared by blending 6% (w/v) FG with 0.02–0.08% (w/v) low-acyl (LAGG) or high-acyl gellan gum (HAGG), respectively. Results showed that 0.06% LAGG and 0.06% HAGG increased the tensile strength of the composite films by 68.5% and 65.7%, respectively. When their addition amounts were increased to 0.08%, the moisture content (15.66% for LAGG, 14.63% for HAGG) and water vapor permeability (WVP, 0.38 for LAGG, 0.34 for HAGG, g·mm/(m 2 ·h·kPa)) of the composite films reached the minimum values, and the oxygen transmission rate (OTR) decreased by 41.6% and 44.3%, respectively, compared with pure FG films. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed that LAGG and HAGG improved the film properties by regulating the microstructure. In the fish meat preservation experiment, the values of thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N), and total viable count (TVC) in the 0.08% HAGG group were 12.95%, 8.12% and 9.88% lower than those in the pure FG film group, respectively, showing the best preservation effect. In conclusion, FG-GG films exhibit excellent comprehensive performance and have the potential to be a new alternative to conventional food preservation films. • The effects of high and low acyl gellan gums on the properties of FG film were evaluated. • Film thermal stability was evaluated using a combination of texture analysis and an incubator. • A method that enables intuitive and rapid evaluation of film thermal stability was developed. • Both kinds of gellan gums significantly improved the thermal stability of FG films. • Adding gellan gum helps to delay the spoilage of fish meat.