May Wee

Doctor of Philosophy, (Food Technology)
Study Completed: 2015
College of Health


Thesis Title
Physico-Chemical Characterisation and Functionality of the Polysaccharide Extracted from the New Zealand Black Tree Fern, Cyathea medullaris (Mamaku)

Read article at Massey Research Online: MRO icon

The New Zealand black tree fern, Cyathea medullaris exudes a mucilage from its stipe when subjected to external stresses.  This mucilage possesses unique physico-chemical properties, being slimy, ropy, and viscoelastic at the same time. Rheological and structural properties were characterised, in order to investigate the events taking place at molecular level which gives rise to these physical manifestations at bulk level. It was hypothesised that the rheological properties (such as shear-thickening) were a result of shear-induced intra- to intermolecular hydrogen bonding between polysaccharide chains. The polysaccharide was also identified to be a glucuronomannan, with glucuronic acid and mannose units being the major components. In vivostudies in rats showed that ingestion of the polysaccharide was able to delay gastric emptying. These findings provide the foundation for developing applications tailored to the properties of the polysaccharide. The polysaccharide therefore has great potential for use in food and non-food applications.  

Associate Professor Lara Matia-Merino
Professor Kelvin Goh