Mechanistic studies of starch retrogradation and its effects on starch gel properties. (November 2021)

• Record Type: Journal Article
• Authors: Liu, Xia; Chao, Chen; Yu, Jinglin; Copeland, Les; Wang, Shujun
• Is Part Of: Food hydrocolloids. Volume 120(2021)
• Publication Date: 2021-11
• Subjects: The short-range molecular order -- Retrogradation -- Gel firmness -- Water mobility -- In vitro enzymic digestion; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2021.106914
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: The influence of residual short-range molecular order on the mechanism of starch retrogradation was examined by measuring functional properties of retrograding starch gels that were prepared by heating starch with different amounts of water at 100 °C. Analyses using X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and laser confocal micro-Raman (LCM-Raman) spectroscopy showed that as short-range molecular range in the gelatinized starch decreased, so did long- and short-range molecular order, gel firmness, water mobility and susceptibility to in vitro enzymic digestion of the corresponding starch as it retrograded over time periods ranging from one to 21 days. The rate and extent of these changes were controlled by the amount of residual short-range molecular order in the starch after gelatinization, which in turn, was a function of the amount of water used for gelatinization. Starch gelatinized with 50–70% water formed had residual short-range molecular order and retrograded more quickly to form stronger gels, whereas starch gelatinized with 75 and 80% retained little structural order and retrograded more slowly, forming softer gels in which the starch crystallites were better-defined. Our study provides new insights into the mechanism of starch retrogradation and its effects on functional properties of retrograded starch gels, which is likely to be of interest for starch in foods and other applications. Graphical abstract: Image 1 Highlights: Effect of residual local order on starch retrogradation was investigated. Low local order in gelatinized starch inhibited the extent of starch retrogradation. Softer gels with better-defined crystallites were formed at high water content. Digestion rate of starch gels increased with local order in gelatinized starch. Retrogradation was controlled by the residual local order in gelatinized starch.