Comparison of structural and physicochemical properties of potato protein and potato flour modified with tyrosinase

Abstract

The present study modified potato protein and flour with tyrosinase to promote the diversification of potato staple foods. The results indicated that tyrosinase treatment markedly altered the secondary structure of proteins. After tyrosinase treatment, the maximum decomposition temperature of potato protein and flour increased from 322.32 to 332.40°C and from 294.24 to 299.61°C, respectively. Tyrosinase treatment remarkably reduced the pasting viscosity of potato flour, that is, the peak viscosity, through reducing viscosity, breakdown, final viscosity, and setback by 32.50, 60.98, 13.04, 68.24, and 74.31%, respectively. In contrast, tyrosinase treatment increased the shear resistance and hardness of the protein and flour gels; the maximum stress values of the protein and flour gels increased from 1.48 to 10.1% and from 6.87 to 14.8%, respectively. Furthermore, tyrosinase treatment promoted viscoelastic properties and structural stability of potato protein and flour. These results may provide an important foundation for the development of novel potato staple foods.