Effects of high temperature, high pressure, and high shear during extrusion on maize starch-fish protein extrudates: Based on physical properties and multiscale structure

This study explored the effects of high temperature, high pressure and high shear during extrusion on maize starch-fish protein extrudates and elucidated the interaction between starch and protein. The results showed that high temperatures promoted an increase in the beta-sheets content of the extrudates and contributed to the fusion of starch and protein. High pressure disrupted the starch's agglomerate structure and protein gel network. With the increase of extrusion strength, the pasting properties of the extrudates were reduced, and the Delta H decreased from 5.87 J/g to 2.70 J/g. Moreover, high shear reduced the short-range orderliness of starch through shear-generated water migration, while promoting the mixing of starch and protein. Interestingly, the synergistic effect of high temperature, high pressure and high shear promoted new hydrogen bonding and hydrophobic interactions between starch and protein. This study provides a scientific basis for considering the unique properties and structure of maize starch-fish protein extrudates.