New method to reduce thickening agent for transport

Cellulose nanofibre (CNF) has applications as a thickening agent in the food industry as well as other industries; however, there have been limitations associated with the transportation of the product through the supply chain. Now researchers from Osaka University have developed a method of dehydrating CNF to a dense powder without affecting its three key properties — the findings have been published in Macromolecular Rapid Communications.

CNF can be used as a thickening agent due to its high transparency and high viscosity, which can be controlled. The amount of CNF needed in water is small, so the most efficient way of transporting it is as a dry powder.

There have been challenges in getting CNF into powder form — removing water via boiling results in the remaining fibres sticking together, producing cloudy liquids. When freeze-drying is used to remove the water, the resulting powder is fluffy and takes up a lot of space. It is also difficult to handle as it is affected by static electricity.

The researchers developed an improved method to remove water, the first step of which is to form an ‘organogel’, consisting partly of organic molecules.

“Our process involves taking a CNF paste in water and dehydrating it by stirring in ethanol. The ethanol is then removed at 30°C, which is a low and cost-effective temperature. After some processing, it can then be redispersed in water simply by stirring,” said senior author Masaya Nogi.

The redispersed product retained the three key properties of CNF thickening agents. A pump spray bottle was used to demonstrate its tuneable viscosity. It was successfully sprayed from the nozzle, which requires a low viscosity, and the ejected droplets did not run from where they landed on an upright surface, which requires high viscosity behaviour.

“The large scale of many industrial processes means that all process improvements can have a big impact on the bottom line,” Nogi said. “Our method of powder creation retains all key properties of CNFs while also enabling effective handling and cheaper transport and storage.”

Organogel-derived CNF powders are expected to have applications across the food, cosmetics and sanitation industries.

Top image caption: Evaporated CNF powders have a small volume and no handling issues related to static electricity (upper left). Their water dispersions are colourless and transparent (upper right) and dispersion droplets formed by spraying do not drip (lower). Image credit: 2023 Nogi et al., Evaporative Dry Powders Derived From Cellulose Nanofiber Organogels to Fully Recover Inherent High Viscosity and High Transparency of Water Dispersion. Macromolecular Rapid Communications.