Researchers urge caution in use of protein nanostructures

Published in Trends in Food Science & Technology, ​the review uses proteins as a case study to explore current knowledge and understanding of nanostructures in foods and the extent to which novel nanostructures may introduce new properties.

“Many of the foods we have been consuming for centuries already contain nanostructures, leading many to assume that they are safe. The extent to which novel nanostructures may afford new risks has not been adequately resolved, however, leading to concern within some consumer groups,” ​the researchers from Australia and New Zealand wrote.​

However, despite the body evidence in support of nanostructures, the researchers said more thorough research is necessary to assess the ‘cytotoxicity’ ​of protein nanostructures.

Evidence has shown that even proteins not previously thought to be associated with disease can be toxic to cells and research suggests it is the intrinsic structural properties of food proteins that induce this toxicity, they said.

Nevertheless supporters of nanotechnology consider that there is plenty of evidence demonstrating the benign nature of the majority of protein nanostructures and instances where they may be harmful to humans are linked to specific protein sequences that can be managed.

Eliminating toxins​

It is possible to neutralise the toxicity of some nanoparticles using a heterogeneous mixtures of proteins, they said. For example, one study showed that the health risks associated with the homogeneous preparation of κ-casein is substantially lessened in a heterogeneous mixture containing β-casein.

“The ability of β-casein to interact with a diversity of relatively hydrophobic proteins in a chaperone manner implies that it could be used in a broader context​.”

As a result, β-casein is now being considered as a nanovehicle to improve the solubility of curcumin, for example.

“This example illustrates how the choice of protein and form of the nanostructure can determine whether a food component may be harmful or health promoting and that each case should be considered individually.”​

Far-reaching implications​

The researchers said the possible application of nanotechnology in food manufacturing and processing is far-reaching - to enhance food bioavailability and improve the colour, texture, flavour and safety properties.

For example, there are a range of new products currently on the market where ‘nanoparticles’ have been utilised to improve the release and delivery of dietary supplements and fat-soluble nutrients.

Other food proteins like lactoglobulin are being considered for their ability to alter food texture, gelling properties and digestibility, they said, and fungal proteins for their potential as surfactants; for example in the creation of air-filled emulsions in low fat ice-cream.

Source: Trends in Food Science & Technology​
DOI: 10.1016/j.tifs.2014.02.003​
“Protein nanostructures in food – Should we be worried?”​

Authors: Jared K. Raynes, John A. Carver, Sally L. Gras, Juliet A. Gerrard