title: Hydrothermal treatment of water yam starch in a non-granular state: slowly digestible starch content and structural characteristics.
abstract: Gelatinized water yam starch was subjected to hydrothermal treatment (25, 30, and 35% moisture content for 1, 8, 16, and 24 h at 100 °C) and characterized by X-ray diffractometry, solid-state ¹³C cross-polarization and magic-angle spinning nuclear magnetic resonance, differential scanning calorimetry, and digestibility analysis. The slowly digestible starch (SDS) content of the starch treated at 30% moisture content for 24 h reached 49.1%, 31.9% higher than that of the control starch. The B-type pattern of native starch was re-crystallized to the A-type by hydrothermal treatment. The SDS content showed negative correlations with T(o), T(p), T(c), and T(r), but showed a positive correlation with melting enthalpy. Furthermore, SDS was positively correlated with hydrothermal reaction time, moisture content, relative crystallinity, and the double-helix proportion. The structural changes in hydrothermally treated water yam starches resulted in the enhancement of SDS.
  
  
  CONCLUSIONS
  The hydrothermally treated water yam starch could be used as a food ingredient for slow-energy supply or dietary fiber.
authors.affiliation: Dept of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National Univ Seoul 151-921, Republic of Korea.
authors.forename: Khanh Son
authors.initials: KS
authors.lastname: Trinh
authors.forename: Chang Joo
authors.initials: CJ
authors.lastname: Lee
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Choi
authors.forename: Tae Wha
authors.initials: TW
authors.lastname: Moon
mesh_terms: D002152:Calorimetry, Differential Scanning; D002236:Carbohydrate Conformation; D055598:Chemical Phenomena; D004043:Dietary Fiber / Q000032:analysis* / Q000378:metabolism; D004063:Digestion; D027742:Dioscorea / Q000737:chemistry*; D005511:Food Handling / Q000379:methods*; D005527:Food, Fortified / Q000032:analysis; D005782:Gels; D006358:Hot Temperature; D019906:Nuclear Magnetic Resonance, Biomolecular; D044367:Phase Transition; D035281:Plant Tubers / Q000737:chemistry*; D011048:Polarography; D056910:Republic of Korea; D013213:Starch / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013997:Time Factors; D014744:Vietnam; D014867:Water / Q000032:analysis*; D014961:X-Ray Diffraction
chemical_list: D004043:Dietary Fiber; D005782:Gels; D014867:Water; D013213:Starch