A Study On Physiochemical Properties Of Cross-Linked Maize Starch With Sodium Trimetaphosphat

Native maize starch was cross-linked in the presence of alkaline sodium trimetaphosphate (STMP) solution with different degrees of substitution (DS). The morphology, molecular structure, crystalline structure, viscosity, thermal properties antienzymatic behavior and adsorption behavior of cross-linked maize starch with STMP have been investigated by means of Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction (XRD), thermogravimetry (TG-DTG), Brabender viscograph, antienzymatic and adsorption experiments.(1) The proper method for processing the STMP cross-linked starches are:the concentration of the starch was40%, the pH=11.0and the temperature is50℃. The cross-linked starch was obtained by the control of the concentration of STMP (0.01-5.0%)and the time(1.0-24h). The DS of the cross-linked starches was from8.574E-5to6.441E-3.(2) As the native maize starch as control, the SEM suggested that the granule of the cross-linked maize starch was as smooth as the native one and the granule was larger along with the increasing DS. The-OH、P-O-C and P=O bond of FTIR suggested that the cross-linked reaction was accrued among the starch molecules. The XRD revealed that the crystal structure of native and cross-linked starch was not changed significantly by the phosphonic esterification process. The cross linking reaction was probable on the amorphous area. The Brabender parameter showed that the maximum viscosity, breakdown and setback was first larger along with the increasing DS and then reduced sharply when the DS up to1.445E-3. As the DS up to5.097E-3, the granule became none-gelatinized. The thermal decomposed behavior of the native and cross-linked starch were observed and the mass loss appeared at a higher temperature as the DS increasing. The antienzymatic experiment revealed that the antienzymatic behavior of gelatinized cross-linked starch was higher than the native with the increasing DS. The antienzymatic behavior of none-gelatinized samples was stronger as the DS increased and the starch which DS is6.441E-3is hard to be digested within5hours. The adsorption behavior of rutin was higher than the native one and the mass of adsorption was higher along with the increasing DS. The mass of adsorption of rutin was3.64mg/g while the DS was6.441E-3.