Does harvesting age matter? Changes in structure and rheology of a shear-thickening polysaccharide from Cyathea medullaris as a function of age.
Carbohydr Polym
; 329: 121757, 2024 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-38286538
ABSTRACT
A shear-thickening polysaccharide from the New Zealand Black tree fern (Cyathea medullaris, commonly known as mamaku) extracted from different age fronds (stage 1 young, stage 2 fully grown and stage 3 old) was characterised in terms of structure and rheological properties. Constituent sugar analysis and 1H and 13C NMR revealed a repeating backbone of -4)-ß-D-GlcpA-(1 â 2)-α-D-Manp-(1â, for all mamaku polysaccharide (MP) samples from different age fronds without any alterations in molecular structure. However, the molecular weight (Mw) was reduced with increasing age, from ~4.1 × 106 to ~2.1 × 106 Da from stage 1 to stage 3, respectively. This decrease in Mw (and size) consequently reduced the shear viscosity (ηs-Stage 1 > ηs-Stage 2 > ηs-Stage 3). However, the extent of shear-thickening and uniaxial extensional viscosity of MP stage 2 was greater than MP stage 1, which was attributed to a greater intermolecular interaction occurring in the former. Shear-thickening behaviour was not observed in MP stage 3.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Carbohydr Polym
Ano de publicação:
2024
Tipo de documento:
Article