Microwave Cooking Enriches the Nanoscale and Short/Long-Range Orders of the Resulting indica Rice Starch Undergoing Storage

Abstract

The chain reorganization of cooked starch during storage plays an important role in the performance of starchy products such as rice foods. Here, different analytical techniques (such as small-angle X-ray scattering) were used to reveal how microwave cooking influences the chain assembly of cooked indica rice starch undergoing storage for 0, 24, or 48 h. While stored, more short-range double helices, long-range crystallites, and nanoscale orders emerged for the microwave-cooked starch than for its conventionally cooked counterpart. For instance, after storage for 24 h, the microwave-cooked starch contained 46.8% of double helices, while its conventionally cooked counterpart possessed 34.3% of double helices. This could be related to the fact that the microwave field caused high-frequency movements of polar groups such as hydroxyls, which strengthened the interactions between starch chains and water molecules and eventually their assembly into double helices, crystallites, and nanoscale orders. This work provides further insights into the chain reassembly of microwave-cooked starch undergoing storage, which is closely related to the quality attributes of starch-based products.

Microwave Assisted Cooking Improves Edible Quality of Germ Rice: Insights of Multiscale Starch Microstructure, In Vitro Digestion, and Flavor

“…The results indicated the structure of native starch granules was adequately destroyed by the hydrothermal effects during cooking. [ 10 ] When studying the changes of morphological structures of boiled jasmine rice under different temperature conditions, it was found that the SEM of the internal endosperm of rice showed the same porous and sponge‐like texture with the increase of cooking temperature. [ 18 ] For electric rice‐cooker cooking treatment, the voids inside the cooked germ rice E2 appeared as a net‐like structure, but this structure was not found for the E1, indicating that more starch leached out during longer cooking time in the electric rice‐cooker.…”

“…The study found microwave-cooked starch showed more nanoscale orders, long-range crystallites, and short-range double helices during storage than the conventionally cooking. [10] Therefore, the influences of cooking methods (electric ricecooker and microwave) on the microstructure, rheological behavior, textural properties, aromatic characteristics, and in vitro starch digestion of the cooked germ rice were systematically evaluated in this study. In addition, the relationship between microstructures and digestion of rice starch under different cooking conditions was also discussed.…”

“…The study found microwave‐cooked starch showed more nanoscale orders, long‐range crystallites, and short‐range double helices during storage than the conventionally cooking. [ 10 ]…”

Food Hydrocolloids: Structure, Properties, and Applications

“…Zeng et al [42] found that the addition of yeast β-glucan and proteins significantly inhibited the gelatinization and retrogradation of starch in whole-wheat bread, resulting in a lower glycemic index. Similarly, Xiong et al [43] reported that microwave-cooked starches showed more shortrange double helices, long-range microcrystals, and nanoscale units than conventionally cooked starches. Notably, little is known about the role of hydrocolloids in the human gastrointestinal tract, leading to uncertainty about the exact mechanism of their prevention of diabetes.…”