Hydrothermal modification of potato starch: Novel blanching and retrogradation impacts on structural and functional...

This study investigated the effects of five blanching techniques (high-humidity hot-air, hot water, steam, vacuum steam, and vacuum steam pulse blanching) on the functional and structural properties of potato starch before and after retrogradation. Blanching alone reduced starch purity from 95.9% to 75.4% and dropped resistant starch from 76.3% to 15.1%, confirming that gelatinization disrupts the native semicrystalline structure. Retrogradation partially reversed these losses: purity recovered to 91.6%, and resistant starch increased to 45.1% under the best conditions. However, peak viscosity continued to fall after retrogradation (from ∼7700 to ∼259 mPa·s), suggesting improved thermal stability despite only partial structural recovery. High-humidity hot-air blanching consistently outperformed other methods, achieving the highest retrogradation degree (16.0%) and best crystallinity restoration (17.7%), with vacuum steam-pulse blanching showing comparable performance. These gentle methods provide a clean-label approach to producing potato starch with enhanced resistant starch content and improved thermal stability during subsequent retrogradation.