Pectin self-assembly and its disruption by water: insights into plant cell wall mechanics. Issue 37 (15th September 2022)

• Record Type: Journal Article
• Authors: John, Jacob; Ray, Debes; Aswal, Vinod K.; Deshpande, Abhijit P.; Varughese, Susy
• Is Part Of: Physical chemistry chemical physics. Volume 24:Issue 37(2022)
• Page Start: 22691
• Page End: 22698
• Publication Date: 2022-09-15
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d2cp01479c
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Changes in microstructure and rheology of pectin–Ca gels during dehydration and rehydration are studied. Depending on the rate of dehydration, reversible or irreversible changes in aggregation of egg-box bundles and strain-stiffening behavior occur. Abstract : Plant cell walls undergo multiple cycles of dehydration and rehydration during their life. Calcium crosslinked low methoxy pectin is a major constituent of plant cell walls. Understanding the dehydration–rehydration behavior of pectin gels may shed light on the water transport and mechanics of plant cells. In this work, we report the contributions of the microstructure to the mechanics of pectin–Ca gels subjected to different extents of dehydration and subsequent rehydration. This is investigated using a pectin gel composition that forms 'egg-box bundles', a characteristic feature of the microstructure of low methoxy pectin–Ca gels. Large amplitude oscillatory shear (LAOS) rheology along with small angle neutron scattering and near infrared (NIR) spectroscopy on pectin gels is used to elucidate the mechanical and microstructural changes during dehydration–rehydration cycles. As the extent of dehydration increases, the reswelling ability, strain-stiffening behavior and yield strain decrease. These effects are more prominent at faster rates of dehydration and are not completely reversible upon rehydration to the initial undried state. Microstructural changes due to the aggregation of egg-box bundles and single chains and the associated changes in the water configurations lead to these irreversible changes.