Nanostructure, morphology and functionality of cassava starch after pulsed electric fields assisted acetylation

• Published in: Food hydrocolloids Vol. 54; pp. 139 - 150
• Main Authors: Hong, Jing, Zeng, Xin-An, Buckow, Roman, Han, Zhong, Wang, Man-sheng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2016
• Subjects: Acetylation; Cassava starch; Fractal; Nanostructure; Pulsed electric fields; Cassava starch; Pulsed electric fields; Nanostructure; Fractal; Acetylation
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2015.09.025

Pulsed electric fields (PEF) assisted acetylation of cassava starch with a higher degree of substitution (DS) of 0.131 was obtained in the presence of 10% (w/w) acetic anhydride after PEF treatment at 2 kV/cm for 51.0 ms. Fourier-transformed infrared spectroscopy showed a characteristic peak of the acetyl group in modified starch at 1730 cm−1. The crystalline region of acetylated starch was destroyed and rearranged as confirmed by X-ray diffraction. Small-angle X-ray scattering indicated that the fractal structure was changed from a surface fractal structure to a mass fractal structure with increasing DS probed. Atomic force microscopy showed that PEF assisted acetylation of starch markedly increased the surface roughness. The prominent freeze-thaw stability of PEF-assisted, acetylated starch demonstrated its potential and superior application in frozen food products. [Display omitted] •A brand-new dual modification method for starch acetylation is proposed.•The highest DS value (0.131) and fitted quadratic mode are proposed upon RSM.•Nanostructure is changed from surface fractal structure to mass fractal structure.•PEF-assisted acetylated starch shows superior application in frozen food products.