Effects of pulsed electric field treatments on some properties of tapioca starch.

Tapioca starch-water dispersions (8.0%, w/w) were subject to pulsed electric fields (PEF) at 30, 40 and 50 kV cm(-1), respectively. The effect of the intense energy input (Q) of PEF treatment (over 28.85 J g(-1)) on the functionality of tapioca starch was investigated. Scanning electron microscopy analysis revealed the dissociation and damage of PEF treated tapioca starch granules. X-ray diffraction analysis demonstrated that tapioca starch tended to transform from crystalline to amorphous structure after PEF treatments. It was found that higher energy input (>49.36 J g(-1)) could destroy the crystal region of tapioca starch. Meanwhile, with increasing electric field strengths, the gelatinization temperature, the gelatinization enthalpy, the peak viscosity and the breakdown viscosity of PEF-treated samples showed a remarkable decrease. These results suggest that PEF treatments would be a promising physical method to modify the properties of starch in order to obtain desired products in food industry.