In vitro digestion and physicochemical characteristics of corn starch mixed with amino acid modified by heat-moisture treatment

Corn starch was modified with amino acid by heat-moisture treatment (HMT) to investigate the formation of slowly digestible starch (SDS). SDS content in native corn starch and heat-moisture treated corn starch were 17.91% and 4.35% respectively, while the maximum SDS content in amino acid-heat treated starches (HMT-amino acid) reached 41.07%. HMT-Lys displayed reduced birefringence brightness at the periphery, while for HMT-Asp, a weaker birefringence region was observed but without apparent Maltese crosses. HMT-amino acid showed higher gelatinization temperature and lower gelatinization enthalpy. After HMT, relative crystallinity of amino acid-heat treated starches decreased. The lower DH and the lowest relative crystallinity had the highest SDS content (41.07%). The results indicated that structural changes of corn starch mixed with amino acid by HMT significantly affected the digestibility. (C) 2017 Elsevier Ltd. All rights reserved.