Impact of ultrasound pretreatment on enzymatically prepared porous corn starch: A comparative study with cold plasma

Porous starch was prepared by enzymatic hydrolysis following pretreatment using a probe ultrasound system with a tip diameter of 6 mm, an applied power of 450 W and a frequency of 20 kHz. In comparison, cold plasma (200 Hz, 60 W) was performed as another independent pretreatment method. Both pretreatments enhanced the efficiency of enzymatic hydrolysis, and the resulting porous starch featured larger and deeper pores. Ultrasound pretreatment produced porous starch (UES) with the largest specific surface area (1.89 m 2 /g), highest total pore volume (4.29 × 10 -3 cm 3 /g), and maximum swelling capacity (42.33 g/g) and solubility (98.01 %). Characterization via XRD and FTIR results confirmed that cold plasma and ultrasound pretreatment greatly lowered the crystallinity and ordered structures of starch, thereby enhancing enzymatic efficiency. The water/oil absorption capacities and methylene blue adsorption kinetics of porous starch were investigated. UES achieved the optimal performance in water/oil absorption capacities and methylene blue adsorption. This study provides theoretical technical support for porous starch production using non-thermal processing and verifies ultrasound’s superiority in efficiently constructing these porous structures.