Exploring the relationship between starch structure and physicochemical properties: The impact of extrusion on highland barley flour

Fei Ge; Yue Sun; Chenxi Yang; Weiwei Cheng; Zhenjiong Wang; Xifeng Xia; Di Wu; Xiaozhi Tang

doi:10.1016/j.foodres.2024.114226

Exploring the relationship between starch structure and physicochemical properties: The impact of extrusion on highland barley flour

Food Res Int. 2024 May:183:114226. doi: 10.1016/j.foodres.2024.114226. Epub 2024 Mar 13.

Authors

Fei Ge¹, Yue Sun¹, Chenxi Yang¹, Weiwei Cheng¹, Zhenjiong Wang¹, Xifeng Xia², Di Wu³, Xiaozhi Tang¹

Affiliations

¹ College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
² Center of Analytical Facilities of Nanjing University of Science and Technology, Nanjing 210094, China.
³ College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China. Electronic address: diwu@nufe.edu.cn.

PMID: 38760145
DOI: 10.1016/j.foodres.2024.114226

Abstract

Highland barley (HB) is an intriguing plateau cereal crop with high nutrition and health benefits. However, abundant dietary fiber and deficient gluten pose challenges to the processing and taste of whole HB products. Extrusion technology has been proved to be effective in overcoming these hurdles, but the association between the structure and physicochemical properties during extrusion remains inadequately unexplored. Therefore, this study aims to comprehensively understand the impact of extrusion conditions on the physicochemical properties of HB flour (HBF) and the multi-scale structure of starch. Results indicated that the nutritional value of HBF were significantly increased (soluble dietary fiber and β-glucan increased by 24.05%, 19.85% respectively) after extrusion. Typical underlying mechanisms based on starch structure were established. High temperature facilitated starch gelatinization, resulting in double helices unwinding, amylose leaching, and starch-lipid complexes forming. These alterations enhanced the water absorption capacity, cold thickening ability, and peak viscosity of HBF. More V-type complexes impeded amylose rearrangement, thus enhancing resistance to retrogradation and thermal stability. Extrusion at high temperature and moisture exhibited similarities to hydrothermal treatment, partly promoting amylose rearrangement and enhancing HBF peak viscosity. Conversely, under low temperature and high moisture, well-swelled starch granules were easily broken into shorter branch-chains by higher shear force, which enhanced the instant solubility and retrogradation resistance of HBF as well as reduced its pasting viscosity and the capacity to form gel networks. Importantly, starch degradation products during this condition were experimentally confirmed from various aspects. This study provided some reference for profiting from extrusion for further development of HB functional food and "clean label" food additives.

Keywords: Dietary fiber; Extrusion; Highland barley; Multi-scale structure; Physicochemical properties; Starch.

MeSH terms

Amylose* / chemistry
Chemical Phenomena
Dietary Fiber / analysis
Flour* / analysis
Food Handling* / methods
Hordeum* / chemistry
Hot Temperature
Nutritive Value
Solubility
Starch* / chemistry
Viscosity
beta-Glucans / chemistry