Nervonic Acid-enriched Structured Lipids: Preparation, Encapsulation, Digestion and Storage Stability

Nervonic acid (NA) is a vital nutrient that plays a significant role in human brain development and maintenance. However, NA has very poor bioavailability in its free fatty acid (FFA) form. By incorporating NA into the phospholipid (PL) structure, the functionality of NA can be enhanced due to the superior bioavailability of PLs compared to triacylglycerol (TAG) or free fatty acids. This thesis elucidated the preparation and encapsulation of NA-enriched structured phospholipid (SPL), followed by the in vitro digestion and storage stability of encapsulated NA-enriched SPL. A preparation method was established to extract pure NA crystals of up to 97.37% from Malania oleifera oil, followed by synthesising NA-enriched structured triacylglycerol (STAG) and PL. Lipases were screened, and the most effective lipase was selected to produce NA-enriched STAG and SPL. Results showed that both NA-enriched STAG and PL have a NA content of 65.57% and 48% incorporated, respectively. NA-enriched SPL was selected for further encapsulation due to its superior bioavailability and less laborious purification method. NA-enriched SPL was encapsulated in freeze-dried nanostructured lipid carrier (NLC-FD), NLC suspension (NLC-S), freeze-dried microcapsule (MC-FD) and conventional emulsion (CV-E). Wall materials were screened, and the parameters were optimised for each formulation based on their physical stability. The encapsulated samples underwent in vitro digestion, and the results show that MC-FD had the highest digestibility (79.54%), followed by CV-E (72.1%), NLC-S (70.32%), NLC-FD (58.49%), and NA-enriched SPL (29.82%). Storage stability was investigated by evaluating the primary and secondary lipid oxidative stability during storage from day 0 to day 90 at 4°C, 25°C and 45°C. The results showed freeze-dried samples (NLC-FD, MC-FD) were more stable with no significant change in physical appearance than suspension or emulsion samples (NLC-S, CV-E). However, NLC-S had the most stable average particle size of approximately 200 nm, while CV-E displayed the lowest physical stability with a significant change in physical appearance and a significant increase in particle size from 200 nm to over 10000 nm on day 14 when stored at 25°C and 45°C. Overall, the current work filled the gaps in the preparation of a NA-enriched SPL and the physicochemical changes during storage and in vitro digestion after encapsulation.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Food Science

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2025

Author dc:creator

• Ang, Geoff

Advisor dc:contributor.advisor

• Young Quek, Siew

• Nervonic acid
• phospholipid
• acidolysis
• transesterification
• structured lipid

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/72938

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/72938