Comparison of fish and mammalian gelatin film properties: A meta-analysis

Edible films (EF) are continuously developed as food packaging alternatives due to their biodegradable properties. EF can be made from polysaccharides, proteins, lipids, and composite components. The use of raw materials certainly affects the properties of EF. Some studies reported that mammalian gelatin films were significantly different from fish gelatin films. However, there have been different results among individual studies. Therefore, the present study would like to obtain a valid conclusion across different studies using a meta-analysis approach. Study selection was performed with the PRISMA guideline. There were six relevant studies and 28 data used for meta-analysis. The statistical analysis was calculated by using Hedges*d. The results show that fish gelatin films had significantly lower (p < 0.05) tensile strength, elastic modulus, water vapor permeability, and transparency compared to mammalian gelatin films. Besides, there were two additional factors that are also discussed such as different film fabrication methods and gelatin concentration. Those seasonal factors were conducted by using subgroup analysis and meta-regression, respectively. The results described that the film production method, i.e., casting and compression molding significantly effect (p < 0.05) the tensile strength and elongation at break. Slightly different from the method, gelatin concentration was significantly affected (p < 0.05) the tensile strength, elongation at break, and water vapor permeability.