Enhancing the nonlinear rheological property and digestibility of mung bean flour gels using controlled microwave treatments: Effect of starch debranching and protein denaturation

Yue Gu; Rong Xu; Tongxun Liu; David Julian McClements; Xiujie Zhao; Jinjin Wu; Mouming Zhao; Qiangzhong Zhao

doi:10.1016/j.ijbiomac.2024.132049

Enhancing the nonlinear rheological property and digestibility of mung bean flour gels using controlled microwave treatments: Effect of starch debranching and protein denaturation

Int J Biol Macromol. 2024 May 2:132049. doi: 10.1016/j.ijbiomac.2024.132049. Online ahead of print.

Authors

Yue Gu¹, Rong Xu¹, Tongxun Liu¹, David Julian McClements², Xiujie Zhao¹, Jinjin Wu¹, Mouming Zhao³, Qiangzhong Zhao⁴

Affiliations

¹ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
² Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA.
³ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technology Research Center, Guangzhou 510640, China.
⁴ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technology Research Center, Guangzhou 510640, China. Electronic address: qzzhao@scut.edu.cn.

PMID: 38704060
DOI: 10.1016/j.ijbiomac.2024.132049

Abstract

In this study, we examined the possibility of using industrial microwave processing to enhance the gelling properties and reduce the starch digestibility of mung bean flour (MBF). MBF (12.6 % moisture) was microwaved at a power of 6 W/g to different final temperatures (100-130 °C), and then its structural and functional properties were characterized. The microwave treatment had little impact on the crystalline structure or amylose content of the starch, but it roughened the starch granule surfaces and decreased the short-range ordered structure and degree of branching. In addition, the extent of mung bean protein denaturation caused by the microwave treatment depended on the final temperature. Slightly denaturing the proteins (100 °C) did not affect the nature of the gels (protein phase dispersed in a starch phase) but the gel network became more compact. Moderately denaturing the proteins (110-120 °C) led to more compact and homogeneous starch-protein double network gels. Excessive protein denaturation (130 °C) caused the gel structure to become more heterogeneous. As a result, the facilitated tangles between starch chains by more linear starch molecules after debranching, and the protein network produced by moderate protein denaturation led to the formation of stronger gel and the improvement of plasticity during large deformation (large amplitude oscillatory shear-LAOS). Starch recrystallization, lipid complexion, and protein network retard starch digestion in the MBF gels. In conclusion, an industrial microwave treatment improved the gelling and digestive properties of MBF, and Lissajous curve has good adaptability in characterizing the viscoelasticity of gels under large deformations.

Keywords: Digestion; LAOS; Lissajous curve; Microwave treatment; Mung bean flour.