Effect of phytochemical extracts on the pasting, thermal, and gelling properties of wheat starch

Abstract

Pasting, thermal and gel textural properties of wheat starch were studied in the presence of phytochemical extracts from pomegranate peel (C18), green tea (C53), Chinese hawthorn (C54), and Chinese gall (C46). All the four extracts increased the breakdown values and reduced the final viscosity. C18, C46, and C53 increased the peak viscosity. C18 and C46 reduced peak time and hot paste viscosity. All the four extracts reduced gel hardness. C46 increased gel adhesiveness. C46 facilitated the gelatinization of starch with earlier onset of To, Tp and Tc and a higher melting enthalpy whereas C18 and C54 prolonged the To, Tp and Tc and decreased the melting enthalpy. All phytochemical extracts caused earlier onset of To and Tp of amylose inclusion complex melting without altering the enthalpy. Scanning electron microscopy revealed that phytochemical extracts could cause looser gel matrices of dried wheat starch gels. Colour observation showed phytochemical extracts imparted different colours to wheat starch gels. © 2008.