Interaction Mechanism Of Corn Starch-Fatty Acid-Hairtail Myosin

In this study,the effects of single or combined effects of corn starch with different amylose content and fatty acids with different unsaturation on the degree of protein aggregation,gel characteristics,rheological properties,intermolecular forces,infrared spectrum and SDS-PAGE of myosin from Hairtail(Trichiurus lepturus)were analysised.The purpose of this work was to provide a theoretical reference for the application of starch-fatty acid complex in surimi products.Main results of this study were as following:1.With the increase of amylose content and added amount of corn starch,the particle size,turbidity,surface hydrophobicity and total SH content of myosin increased significantly.The maximum fluorescence intensity of the endogenous fluorescence spectrum was reduced to 2545,2254,and 2200,respectively,and fluorescence quenching occurred.The addition of starch did not significantly influence the peak shape of FTIR for myosin before and after heating.The secondary structure of myosin was changed from α-helix toβ-sheet after heating.Laser confocal microscopy and SDS-PAGE results showed that starch molecules existed in myosin network structure as a filler.The gel strength of myosin increased to 54.17 g·mm,60.65 g·mm,and 73.25g·mm with the increase of the amylose content and the added amount of starch,respectively.The highest water holding capacity was 38.03% when 3%high amylose corn starch was added into mysion.The intermolecular forces of starch-myosin gel are mainly hydrophobic interactions.The addition of starch did not significantly change the functional group and secondary structure content of the myosin gel.2.The strength and water holding capacity of myosin gel tended to increase firstly and then decrease with the increase of fatty acid unsaturation.When linoleic acid was added,the maximal gel strength and water holding capacity of myosin were 334.09 g·mm and 22.13%,respectively.The results of rheology and electrophoresis showed that fatty acids were encapsulated in the gel network structure in the form of oil droplets.The intermolecular forces of protein gels are mainly hydrophobic interactions.FTIR showed that fatty acids have no significant effect on the protein molecular backbone.3.The gel strength and water holding capacity of the ternary composite gel are higher than those of the starch or fatty acid added alone.The G′ of the ternary composite system is significantly higher than that of the binary composite system.The intermolecular forces of the ternary composite system are mainly hydrophobic interactions.Due to the effect of fatty acids on starch gelatinization,the ionic bond content was changed.The results of infrared spectrum and electrophoresis spectrum suggested that the combined form of the ternary composite system might be that the oil droplets are wrapped with gelatinized starch and are embedded in the gel network structure together.