Innovation enables low-cost encapsulation for timed release of bioactives

The liquid-liquid encapsulation system introduces a drop of core material through a nozzle, which impacts on a host bath, containing a floating shell layer on the surface.

The core material then interacts with the shell layer, creating a stable encapsulation that protects the core material and enables a timely release of the cargo material to a targeted area.

“Our encapsulation can be used for adding flavourants to different food products,” said Sushanta Mitra, project lead and executive director at the Waterloo Institute for Nanotechnology.

“We have used coffee as a core with food-grade alginate as the shell material and have also encapsulated omega-3 (core) with food-grade polydimethylsiloxane (PDMS) as the shell,” he added.

“We have demonstrated multicore system in one parcel, where we wrapped honey, maple syrup, and ferrofluid (a functional nanoparticle-based solution). We then used a magnet to manipulate the composite parcel.”

Example applications for the nutraceutical and beverage sectors

Mitra, who is also professor of mechanical and mechatronics engineering at the University of Waterloo, said that the use of the soft gel-filling encapsulation machine in the nutraceutical industry could reduce operating costs.

In addition, the method could expand the development and production of new products, as multiple core materials can be encapsulated and delivered in the same parcel.

Other examples could be applied to beverages, where flavoured capsules could be introduced that would provide added tastes and on-demand release of flavours inside packaged drinks.

“The key to this technology is that everything is in liquid state – the core, the shell, and finally submerged inside a liquid bath,” said Mitra. "It is ultrafast, with each encapsulation taking only 50 milliseconds.

“This technology is at least 5,000 times less energy intensive and it avoids the introduction of any microplastics in the encapsulation process.”

Addressing issues of storage, temperature, and humidity

With the encapsulation of core materials in liquid form, the issue arises of how the finished product responds to storage, particularly with changes in temperature and/or humidity.

“We can use food-grade dye, functional materials as core,” explained Mitra. “The finished product with a proper shell can be an effective barrier for moisture. We have also used a temperature-sensitive polymer, which hardens based on temperature.”

The research team have also demonstrated the release of the core material by pressing with fingers (soft nature of the shell material) and by bite of the teeth (hardening of the shell material).

Currently in the prototype phase, the machine has four injection nozzles that could produce up to 200,000 encapsulated cargo units per hour.

“We can really scale it further by increasing the number of nozzles to 20, which will allow a throughput of around one million encapsulated cargos per hour,” said Mitra.

Scaling up to a customer-ready, benchtop encapsulation machine

The researchers are now working with partners and product manufacturers in the Eindhoven region of the Netherlands to integrate the curing stage with their prototype, so the encapsulated cargo could be extracted as individual capsules on demand if needed.

Looking ahead, they are on the hunt for commercial partners to develop a fully functional minimum viable product (MVP) and scale it up to a customer-ready benchtop encapsulation machine.

“We are keen to engage with customers in the nutraceuticals and food and beverage sectors to test our technology and increase the application domains of this innovative, scalable, liquid-liquid encapsulation system,” said Mitra.