2Structural characterization and physicochemical properties of arrowhead resistant starch prepared by different methods

Resistant starch (RS) served as a novel functional ingredient has attracted much attention. In this paper, the structure and physicochemical properties of arrowhead resistant starch (ARS) prepared by subcritical water (SW-ARS), ultrasound-subcritical water (USW-ARS), autoclaving (AM-ARS) and ultrasound-autoclaving (UAM-ARS) were investigated. The results showed that the structure of starch granules was completely disrupted and the size of starch granules was obviously increased. SW-ARS, USW-ARS, AM-ARS and UAM-ARS exhibited a B-type crystallinity pattern with different degree of crystallinity. UAM-ARS displayed the highest molecular order with the highest degree of double helixes while SW-ARS, USW-ARS and AM-ARS showed a lower degree of molecular order than that of arrowhead native starch (ANS).The ANS and ARS prepared by four methods possessed high gelation enthalpy in which UAM-ARS had the highest gelation enthalpy, indicating that they had excellent thermostability.Therefore, ANS and the resulting ARS may be a promising starch-based material. All these results are expected to provide information on the preparation and application of ANS and ARS. (C) 2020 Elsevier B.V. All rights reserved.