Retrogradation Behavior and Molecular Mechanism of Starch under High Moisture Content

Abstract

For the first time, the retrogradation behavior of starch during storage under high moisture content was studied from the perspective of short-range ordering of gelled starch. The study found that under high moisture content, the formation of crystal structure was not detected in short-term (1 day) retrogradation, but the short-range ordered structure of amorphous gelled starch increased. By extending the retrogradation time to 7 days, the starch formed an obvious crystal structure. After further extending the retrogradation time, the degree of starch retrogradation increased. Low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) analysis results indicated that free water was separated from the high moisture content starch gel during the retrogradation process. From the above studies and other results, at high moisture content, gelatinized starch cannot form a crystal structure during short-term storage, but its short-range order increased. As the regeneration time increased, the crystal structure could be formed.

Keywords

• short-range order
• gelatinized wheat starch
• retrogradation
• crystal structure
• water mobility