Relationship between starch fine structure and simulated oral processing of cooked japonica rice

Guodong Liu; Ruizhi Wang; Shaoqiang Liu; Man Xu; Lunan Guo; Hongcheng Zhang; Haiyan Wei

doi:10.3389/fnut.2022.1046061

Relationship between starch fine structure and simulated oral processing of cooked japonica rice

Front Nutr. 2022 Nov 3:9:1046061. doi: 10.3389/fnut.2022.1046061. eCollection 2022.

Authors

Guodong Liu^{1

2

3}, Ruizhi Wang^{1

2

3}, Shaoqiang Liu^{1

2

3}, Man Xu^{1

2

3}, Lunan Guo⁴, Hongcheng Zhang^{1

2

3}, Haiyan Wei^{1

2

3}

Affiliations

¹ Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China.
² Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou, China.
³ Research Institute of Rice Industrial Engineering Technology of Yangzhou University, Yangzhou, China.
⁴ School of Food Science and Engineering, Yangzhou University, Yangzhou, China.

Abstract

Background: Simulated oral processing can be used to evaluate the palatability of cooked rice. Previously, we established a simulated oral processing method using a texture analyzer equipped with a multiple extrusion cell probe (TA/MEC). However, the relationship between oral processing and starch fine structure remains unknown.

Methods: In this study, we analyzed the oral processing properties using TA/MEC and characterized the starch fine structure of japonica rice by size-exclusion chromatography (SEC) and fluorophore-assisted capillary electrophoresis (FACE). The relationship between starch fine structure and oral processing of cooked japonica rice was further investigated.

Results: Cooked rice structure contains fast-breakdown (Type I structure), slow-breakdown (Type II structure) and unbreakable structures (Type III structure). Fast-breakdown and slow-breakdown structure were positively correlated with the content of amylose and shorter amylopectin branches. The content of longer amylopectin branches was positively correlated with the contribution of unbreakable structure.

Conclusion: The results indicated that cooked japonica rice varieties with more amylose and shorter amylopectin branches tend to form a harder texture and need more work to break down the fast and slow breakdown structures related to rice kernel fragmentation. Meanwhile, cooked japonica rice varieties possess stronger molecular entanglements due to their longer amylopectin branches and contribute more to the breakdown of unbreakable structures. These results can guide breeders to select rice varieties with desirable eating qualities for cultivation.

Keywords: eating quality; japonica rice; oral processing; palatability; starch fine structure.