Microwave treatment alters the fine molecular structure of waxy hull-less barley starch

Xiaojing Chen; Mengting Ma; Xingxun Liu; Zekun Xu; Chuangchuang Zhang; Zhongquan Sui; Harold Corke

doi:10.1016/j.ijbiomac.2021.11.007

Microwave treatment alters the fine molecular structure of waxy hull-less barley starch

Int J Biol Macromol. 2021 Dec 15;193(Pt B):1086-1092. doi: 10.1016/j.ijbiomac.2021.11.007. Epub 2021 Nov 4.

Authors

Xiaojing Chen¹, Mengting Ma¹, Xingxun Liu², Zekun Xu¹, Chuangchuang Zhang¹, Zhongquan Sui³, Harold Corke⁴

Affiliations

¹ Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
² Lab of Food Soft Matter Structure and Advanced Manufacturing, College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China.
³ Department of Food Science & Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: zsui@sjtu.edu.cn.
⁴ Biotechnology and Food Engineering Program, Guangdong Technion-Israel Institute of Technology, Shantou 515063, China; Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel. Electronic address: harold.corke@gtiit.edu.cn.

PMID: 34742840
DOI: 10.1016/j.ijbiomac.2021.11.007

Abstract

Waxy hull-less barley kernels and their isolated starches were exposed to different microwave conditions (power 640, 720, and 800 W, time 60, 120 and 180 s) and changes in morphology, particle size, digestibility, rheological properties, and molecular structure were measured and analyzed. Microwave treatment caused roughness and deformation of granular surfaces, and an increase in granule size. After treatment, the in vitro digestibility of starch was increased, i.e., the RDS increased, but the RS decreased. Microwave treatment decreased the K values of the in-kernel MWI WHBS. Dynamic rheological results showed that the in-kernel MWI WHBS pastes had lower T_G'max, and higher G'_max, G'₉₀_°C, G'₂₅_°C, G'_0.1Hz and G'_20Hz after treatment. The chain-length distribution did not significantly change after microwave treatment. However, the results for molecular size distributions showed that the peaks of amylopectin (R_h = ~100 nm) shifted left and right, indicating that the molecular volume might become smaller or larger under different processing conditions. The primary effects of microwave treatment may be loosening the molecular structure and cutting main chains of amylopectin.

Keywords: Functional properties; Molecular size distribution; Waxy hull-less barley.

MeSH terms

Hordeum / chemistry*
Microwaves*
Molecular Structure
Starch / chemistry*

Substances

Starch