Dynamic evolution of structure and digestibility in potato starch-konjac glucomannan composites: Targeting DSC...

This study provided a targeted thermal processing strategy based on the characteristic DSC transition temperatures (To, Tp, Tc) to enhance and stabilize the interaction between potato starch-konjac glucomannan (PS-KGM). Heating at MTo, MTp, and especially MTc progressively disrupted starch granules and promoted the release of soluble starch, which interacted with KGM via hydrogen bonding and chain entanglement. This interaction stabilized the mixture and inhibited phase separation, even after 12 h of storage. Melting treatments markedly enhanced the thermal stability of the PS-KGM composite, as evidenced by significantly lower SP and WSI and by higher melting temperatures that increased from 59.10 to approximately 77 °C. Pasting properties were substantially improved, with BD significantly decreased from 5009 to approximately 400 mPa·s while FV increased from 3363 to approximately 8000 mPa·s. Furthermore, melting treatments progressively disrupted starch ordered structures (reduced relative crystallinity and lamellar disassembly), which facilitated soluble starch release and interaction with KGM. In vitro digestibility results showed a decrease in RDS and an increase in SDS and RS contents. These findings highlighted that targeted thermal processing at DSC transition temperatures was an effective strategy for structuring functional properties of starch-hydrocolloid composites with improved stability and tailored digestibility.