Enhanced Starch-Hydrocolloid Synergism Through Critical Melting and Freeze-Thawing: Mechanism of Structural Weakening and Chain Reassociation

The study aimed to enhance the interchain entanglement between tapioca starch (TS) and hydrocolloids by partially weakening starch structure and promoting chain reassociation, using critical melting combined with freeze-thawing treatment (CMFT). Compared to simple blends (SBL), CMFT induced partial structural disruption and facilitated soluble starch release, likely promoting chain entanglement with hydrocolloids to form large reorganized clusters with a rough granular surface. The observed structural and functional changes support this interpretation. CMFT reduced relative crystallinity from 25.88% (TS) to ~20%, while preserving granular integrity, and increased gelatinization temperatures by ~3 °C. The CMFT-prepared composite showed significantly improved pasting properties, with PV and FV rising from 2526.50 and 2087.00 (TS) to ~2700 and ~2400 mPa·s, respectively. CMFT transformed the weak, elongated TS paste into a cohesive, structurally integrated network with ~3-fold higher gel hardness and substantially reduced digestibility (RS content increased from 43.3% to approximately 60%). The study provides an effective strategy to enhance TS-hydrocolloid interaction by partially weakening starch structure and chain reassociation for designing starch-based ingredients with tailored functional properties.