Effects of sugar beet pectin on the pasting, rheological, thermal, and microstructural properties of wheat starch.

The effects of addition of sugar beet pectin (SBP) on the pasting, rheological, thermal, and microstructural properties of wheat starch (WS) were investigated. Results revealed that SBP addition significantly increased the peak viscosity, trough viscosity, breakdown value, final viscosity, and setback value of WS, whereas decreased the pasting temperature. SBP raised the swelling power (from 13.44 to 21.32 g/g) and endothermic enthalpy (ΔH, from 8.17 to 8.98 J/g), but decreased the transparency (from 9.70 % to 1.37 %). Regarding rheological properties, WS-SBP mixtures exhibited a pseudo-plastic behavior, and SBP enhanced the viscoelasticity, but decreased the deformability. Particle size distribution analysis confirmed that SBP promoted the swelling of WS granules. Fourier-transform infrared spectroscopy results suggested that the interactions between SBP and WS did not involve covalent bonding, and the formation of ordered structure was inhibited by SBP addition. Additionally, scanning electron microscopy observation found that the gel network of WS-SBP mixtures became more irregular, pore size gradually decreased, and the wall became thinner as the SBP concentration increased. These results indicated that SBP is a promising non-starch polysaccharide that can enhance the processing properties of WS.

Effects of the degree of substitution of octenyl succinic anhydride on the physicochemical characteristics of adlay starch.

Impact of octenyl succinic anhydride (OSA) esterification on the structural, thermal, pasting, and emulsifying characteristics of adlay starch was investigated. The degree of substitution (DS) increased significantly from 0.008 to 0.025 with increasing OSA quantity, and the bands intensity at 1724 cm-1 and 1572 cm-1 in Fourier transform infrared spectroscopy increased with increasing DS. OSA modified starch showed unaltered orthorhombic diffraction pattern and morphological structure in native adlay starch, but gelatinization temperatures and enthalpy decreased significantly. Higher DS values lowered iodine binding capacity (from 1.37 to 0.77) and a shift in the maximum absorbance wavelength toward the shortwave direction was observed (from 530 nm to 510 nm). Significant increases were observed in peak, through, breakdown and final viscosities upon OSA esterification, while the pasting temperature decreased. Furthermore, contact angles increased significantly from 27.4° to 73.4° with increasing DS, and OSA-starch exhibited superior emulsion stability. Therefore, esterification with OSA effectively modified adlay starch to meet industrial demands and enhance its functional properties.