The phase transformations in starch during gelatinisation: a liquid crystalline approach

Area of Science:

• Food science and technology
• Polymer science
• Biophysics

Background:

• Starch gelatinization is a complex process involving structural changes in amylopectin.
• Amylopectin's molecular behavior can be analogized to chiral side-chain polymeric liquid crystals.
• Understanding these behaviors is crucial for controlling starch-based product properties.

Purpose of the Study:

• To examine the molecular phase behavior of amylopectin during gelatinization.
• To investigate the influence of water content and temperature on amylopectin structure.
• To establish a theoretical framework for starch granule phase transitions.

Main Methods:

• Small-angle X-ray scattering (SAXS)
• Wide-angle X-ray scattering (WAXS)
• 13C cross-polarization magic-angle spinning (CP/MAS) Nuclear Magnetic Resonance (NMR) spectroscopy

Main Results:

• Three key parameters characterize amylopectin phase behavior: lamellar order (psi), double helix orientation (phi), and helicity (h).
• Water content significantly affects the coupling between double helices and the backbone, influencing phase transitions.
• Temperature acts as a critical factor in dictating the phase adopted by amylopectin within starch granules.

Conclusions:

• Water content is the primary determinant of amylopectin phase behavior during gelatinization.
• The study provides a new theoretical framework for understanding starch granule structure and transitions.
• This research offers insights into controlling starch properties through molecular-level manipulation.