Effects of Extrusion‐Assisted Wet‐milling Isolation on Physicochemical Properties of Corn Starch

Abstract

The yield, physicochemical properties, and digestibility of corn starch isolated by conventional wet‐milling (CS), extrusion‐assisted H2SO3 wet‐milling (EHS), and extrusion‐assisted l‐cysteine wet‐milling (ELS) are investigated. The yield of EHS is significantly higher than that of CS and ELS (p < 0.05). There are no significant differences (p > 0.05) in purity among isolated starches. The results of scanning electron microscopy, polarized light microscopy, X‐ray diffraction, Fourier‐transform infrared spectroscopy, and differential scanning calorimeter reveal that extrusion induced unobvious changes in morphology, surface, crystalline pattern, ordered structures, and thermal properties of isolated starch (p > 0.05). However, the swelling power, solubility, L∗ value, and peak viscosity of EHS are higher than those of ELS and CS. Extrusion‐assisted treatment effectively improves the freeze‐thaw stability and digestibility of isolated starch. The results of this study suggest that the extrusion‐assisted wet‐milling method can be used as an ideal alternative to conventional wet‐milling in the isolation of corn starch.