Gelatinization behavior of starch: Reflecting beyond the endotherm measured by differential scanning calorimetry

• Published in: Food chemistry 2019-06, Vol.284, p.53-59
• Main Authors: Liu, Yi, Yu, Jinglin, Copeland, Les, Wang, Shuo, Wang, Shujun
• Format: Article
• Language: English
• Subjects: Calorimetry, Differential Scanning; Gelatin - chemistry; Gelatinization; Heating time; Hot Temperature; Starch - chemistry; Temperature; Thermodynamics; Water - chemistry; Water content; Wheat starch; X-Ray Diffraction
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2019.01.095

•New insights into starch gelatinization were provided in this study.•Gelatinization initiated earlier than onset temperature of DSC endotherm.•Longer heating caused greater structural disruption at high water content.•DSC endotherm does not represent fully behavior of starch gelatinization. In this study, the gelatinization behavior of wheat starch was investigated using starch-water mixtures that were heated under different conditions. Heating starch-water mixtures at 50 °C, a temperature below onset temperature (To) of starch gelatinization, resulted in disruption of long- and short-range ordered structure, as measured by differential scanning calorimetry, X-ray diffraction and laser confocal micro-Raman spectroscopy, and the extent of disruption was greater when starch was heated at higher water content. At low water content (23–44%), heating duration had little effect on gelatinization behavior of starch, whereas at higher water content (54–75%), longer duration of heating resulted in greater disruption of multiscale structure of starch. From this study, we concluded that the gelatinization endotherm of starch does not represent the complete gelatinization behavior, and starch gelatinization initiates earlier than To. Longer duration of heating caused a greater disruption of starch structure at high water content than at low water content.