The oxidative stability of omega-3 oil-in-water nanoemulsion systems suitable for functional food enrichment: A systematic review of the literature

There is growing demand for functional food products enriched with long chain omega-3 polyunsaturated
fatty acids (LCv3PUFA). Nanoemulsions, systems with extremely small droplet sizes have been shown to
increase LCv3PUFA bioavailability. However, nanoemulsion creation and processing methods may impact
on the oxidative stability of these systems. The present systematic review collates information from studies
that evaluated the oxidative stability of LCv3PUFA nanoemulsions suitable for use in functional foods. The
systematic search identified seventeen articles published during the last 10 years. Researchers used a range
of surfactants and antioxidants to create systems which were evaluated from 7 to 100 days of storage.
Nanoemulsions were created using synthetic and natural emulsifiers, with natural sources offering
equivalent or increased oxidative stability compared to synthetic sources, which is useful as consumers are
demanding natural, cleaner label food products. Equivalent vegetarian sources of LCv3PUFA found in fish
oils such as algal oils are promising as they provide direct sources without the need for conversion in the
human metabolic pathway. Quillaja saponin is a promising natural emulsifier that can produce
nanoemulsion systems with equivalent/increased oxidative stability in comparison to other emulsifiers.
Further studies to evaluate the oxidative stability of quillaja saponin nanoemulsions combined with algal
sources of LCv3PUFA are warranted.