Regulating the physicochemical and structural properties of different starches by complexation with tea polyphenols

The effects of tea polyphenols (TPs) on the physicochemical and structural properties of wheat starch (WS), potato starch (PS) and pea starch (PAS) were investigated. Rapid viscosity analysis showed that the pasting viscosity parameters of WS and PAS increased but the above pasting properties corresponding to PS decreased after complexing with TPs, which reflected TPs had different effects on pasting behavior of different starches. Dynamic rheological results manifested TPs could decline the G′ and G″ of starch-TPs complexes in a concentration-dependent manner, indicating that the addition of TPs weakened the viscoelasticity of different starch gels. The decrease in thermal stability of the complex according to thermogravimetric data verified that TPs could interfere with the gel structure of different starches. Fourier infrared spectroscopy and X-ray diffraction results revealed that TPs mainly altered the short-range ordered structure of starches through non-covalent interaction while showing little effect on long-range ordered structure. Scanning electron microscopy micrographs showed that the starch-TPs complexes had looser and more porous microstructures, further verifying the interaction between starch and TPs. The results in this study reveal that blending with TPs shows different regulation effects on physicochemical and structural properties of different starches effectively.