Effect of Deproteinization or Defatting on Gelatinization and in Vitro Digestion Properties of Coix Starch

The effect of the removal of starch granule-associated proteins (SGAPs) and/or lipids on pasting and in vitro digestion properties of adlay starch was investigated. The results showed that the removal of both SGAPs and lipids increased the swelling power, solubility, and rapidly digestible starch (RDS) and slowly digestible starch (SDS) contents and decreased the ratio of peak intensities at 1045/1022 cm^-1, peak viscosity, trough viscosity, breakdown viscosity and resistant starch (RS) content. The removal of SGAPs significantly increased the gelatinization transition temperature and the gelatinization enthalpy and significantly decreased the onset gelatinization temperature. The effect of the removal of SGAPs on the short-range ordered structure and digestibility of adlay starch was more pronounced than that of the removal of lipids. The thermal properties of adlay starch were not significantly affected by the removal of lipids, and the crystal type was not significantly affected by the removal of SGAPs and lipids. The results have potential value for understanding the starch characteristics of adlay and for the application of adlay starch in food processing.