Structural characteristics of low-digestible sweet potato starch prepared by heat-moisture treatment

• Published in: International journal of biological macromolecules Vol. 151; pp. 1049 - 1057
• Main Authors: Na, Jong Hee, Kim, Ha Ram, Kim, Yang, Lee, Joon Seol, Park, Hyun Jin, Moon, Tae Wha, Lee, Chang Joo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.05.2020
• Subjects: Heat-moisture treatment; Hot Temperature; Humidity; Ipomoea batatas - chemistry; Molecular Structure; Polymerization; Slowly digestible starch; Spectrum Analysis; Starch - chemistry; Starch - ultrastructure; Sweet potato starch; Sweet potato starch; Slowly digestible starch; Heat-moisture treatment
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2019.10.146

•Sweet potato starch was subjected to heat moisture treatment.•Optimal conditions for HMT were established using response surface methodology.•Structural characteristics of SDS + RS and RS fractions were examined.•Significant differences were indicated in structural characteristics of SDS and RS. The objectives of this study were to optimize the conditions for the preparation of sweet potato starch containing a high proportion of slowly digestible starch (SDS) by heat-moisture treatment (HMT), and to investigate the structural properties of SDS and resistant starch (RS) fractions isolated from this modified starch. Response surface methodology evaluation of considering temperature, time, and moisture content was conducted to determine the HMT condition for maximizing SDS yield. Maximum SDS content (50.9%) was obtained after 8.6 h at 113 °C with 22.8% moisture level. Scanning electron micrographs of RS fractions displayed growth ring structure and hollow regions. X-ray diffraction patterns of SDS + RS and RS fractions were not changed by HMT. Gelatinization enthalpy of the SDS + RS fraction was decreased more than that of the RS fraction. The results indicated that the SDS fraction consisted of less perfect crystallites and amorphous regions, whereas the RS fraction was composed mostly of crystalline regions.