Effect of Vacuum Treatment on the Characteristics of Oxidized Starches Prepared Using a Green Method

Abstract

Vacuum‐assisted oxidized corn, cassava, and canna starches are prepared using a green method (based on hydrogen peroxide with microwave heating) under optimized conditions. The objective of this study is to evaluate the effect of vacuum treatment on the oxidation of starch. The physicochemical, pasting, thermal, and structural characteristics of vacuum oxidized starches are investigated, and native and non‐vacuum oxidized starches are used for comparison. Physicochemical properties are confirmed by solubility, light transmittance, and freeze–thaw stability; pasting properties are observed using a rapid visco analyzer (RAV); thermal properties are measured via differential scanning calorimetry (DSC); and structures are described using Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), and scanning electron microscopy (SEM). Vacuum oxidized starches show greater solubility and light transmittance, but lower viscosity and swelling power than native and non‐vacuum oxidized starches, and they are more effective in decreasing peak, breakdown, setback, and final viscosities than non‐vacuum oxidized starches. Gelatinization enthalpies of the oxidized starches are reduced, especially for the vacuum‐assisted starches. The results of structural work suggest that the oxidation reaction for both the vacuum and non‐vacuum oxidation occurs in the amorphous starch regions. This green method of vacuum‐assisted oxidation of starch is concluded to be feasible.