Structural and functional properties of collagen from tilapia scales pretreated by heat-assisted ionic liquids

This paper explores the structural and functional properties of collagen from tilapia scales pretreated by heat-assisted ionic liquids (ILs). Results show that the solubility of collagen was significantly influenced by the type and concentration of ILs. With the increase of IL concentration, a remarkable decrease in solubility of collagen was seen. Fluorescence spectra show that heat and IL pretreatments induced the exposure of chromophores. Changes in sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that subunits of collagen regenerated from most of the IL solvent systems were not destroyed. The functional properties of regenerated collagen were evaluated by gel strength, viscosity, water-binding capacity, and emulsifying capacity. Results show that all heat-assisted ILs pretreatments improved the gel strength and viscosity, and the highest gel strength and viscosity were both obtained in the collagen pretreated by heat-assisted [EMIM]Cl. Heat-assisted [BMIM]BF4 pretreatment exhibited the lowest water-binding capacity. Heat-assisted [BDMIM]Cl pretreatment indicated superior effect on improving emulsifying capacity than other pretreatments due to its ability to break most of the hydrogen bonds in collagen molecules, resulting in the formation of new re-aggregates with higher solubility and more hydrophobic groups.