Phosphorylation of Maize Starch Enhanced with High-Voltage Electrical Discharge (HVED) Instead of Thermal Treatment.

The aim of this research was to explore the use of a high-voltage electrical treatment (HVED) as a substitute for heating during the phosphorylation of maize starch. Starch was treated with HVED, phosphorylated with Na ₂ HPO ₄ or Na ₅ P ₃ O ₁₀ with and without thermal treatment and phosphorylated in combination with HVED prior to and after the chemical modification. When starch was phosphorylated with Na ₂ HPO ₄ , HVED was more efficient in catalyzing reaction (3.89 mg P/kg for 30 min HVED in relation to 0.43 mg P/kg for thermal treatment), whereas with Na ₅ P ₃ O ₁₀ similar P content was achieved as with thermal treatment (0.76 P/kg for 30 min HVED in relation to 0.86 mg P/kg). The order of HVED and chemical reactions did not have a marked effect on phosphorous content. In combination with Na ₂ HPO ₄ , HVED pre-treatment had a more pronounced effect on the solubility and water absorption, whereas post-treatment was favoured with Na ₅ P ₃ O ₁₀ . Mean diameter was increased by all treatments, where HVED had a marked effect. Enthalpy of gelatinization ranged from 11.76 J/g for starch treated with Na ₅ P ₃ O ₁₀ and 10 min-HVED to 13.58 J/g for Na ₅ P ₃ O ₁₀ treated sample. G' and G″ increased after both thermally and HVED enhanced phosphorylations, with a slightly more pronounced effect of the HVED.