Effect of temperature during acetylation and heat moisture treatment on the structural and physicochemical properties and application of wheat starch

Some modification techniques have been developed to improve positive attributes and increase application of native starch. In this study, acetylated wheat starch was synthesized using maleic anhydride (MA) and the effect of acetylation temperature and heat moisture treatment (HMT) on the starch was examined. After acetylation modification, the thermal stability of starch decreased except that its freeze–thaw stability increased. Fourier transform infrared spectroscopy showed two new peaks at 1720 and 1570 cm−1 on acetylated starch because of CO and RCOO−, respectively. X-ray diffraction suggested the modification altered the relative crystallinity but not crystalline type. Moreover, temperature controlled the reactions types of MA, and high temperature could promote the formation of crosslinked starch which revealed by the gelatinization to begin at a higher temperature. Starch that acetylated at 30 °C exhibited the higher final viscosity (3674.5 cP) and swelling capacity (18.6 g/g) than those of native starch (871.7 cP and 13.5 g/g, respectively), and counterpart that acetylated at 65 °C or HMT showed increased resistant starch content (5.1%–7.7%) compared with the native wheat (2.8%). Additionally, the stability of the free sulfhydryl, disulfide bond of frozen dough which contained modified starch was improved. Therefore, acetylated starch could be developed as a potential candidate for foods.