Effect of CaCl₂-Induced Surface Gelatinization on Enzymatic Porous Starch

Porous starch (PS) is widely used in food, pharmaceutical, and environmental industries for its high adsorption capacity and controlled release properties. To explore how surface gelatinization affected enzymatically prepared PS, corn starch was first modified via surface gelatinization using a CaCl₂ solution and then treated with α-amylase and amyloglucosidase to synthesize PS. Its structural and functional characteristics were subsequently analyzed. The findings demonstrated that the CaCl₂ solution facilitated the surface gelatinization and enhanced the enzymatic hydrolysis of natural starch. The yield, specific volume, water solubility, swelling power, and oil absorption capacity of PS pretreated with CaCl₂ solution were improved. After 40 min of processing, the yield, specific volume, and oil absorption capacity of PS reached the optimal state, increasing by 19.90%, 91.19%, and 32.84%, respectively. Consequently, its fisetin encapsulation efficiency (93.67%) and loading capacity (8.03%) were also higher than those of non-pretreated PS, attributed to the reduced short-range structure and crystallinity in the CaCl₂-pretreated PS. The DPPH and ABTS radical scavenging activities of CaCl₂-pretreated PS/fisetin (PS/FIT) exceeded those of the non-pretreated PS/FIT and free fisetin. These findings highlight the potential of CaCl₂ pretreatment as an effective strategy to enhance the functional properties of enzymatic PS.