Smuggling medicines in food

US scientists have encapsulated a nutraceutical - a dietary supplement with medicinal benefits - inside hydrocolloids to deliver it intact into the human body in food.

Currently, nutraceuticals’ applications in food are ’limited by poor water solubility and instability under normal processing and storage conditions’, says Srinivas Janaswamy from Purdue University. To address this problem, Janaswamy and his team encapsulated curcumin molecules (a plant phenol found in turmeric with anti-cancer, anti-inflammatory and anti-obese properties) inside water pockets in crystalline hydrocolloid fibres. 

Hydrocolloids - in which the colloid particles are dispersed in water - are already used as thickeners and gelling agents in food. The hydrocolloid Janaswamy’s team used was a sodium salt of iota-carrageenan, which is cheap and holds a generally recognised as safe (GRAS) status. It belongs to a family of polysaccharides extracted from marine algae for use in food and pharmaceutical applications.

As hydrocolloids are mostly amorphous, the group faced a challenge in preparing crystalline, well-oriented fibres containing water pockets to allow the curcumin to be embedded within. 

’This arrangement will certainly aid in serving as a stable platform, as well as providing 

protection for nutraceuticals during the delivery process,’ says Janaswamy.

The team prepared the fibres by dissolving iota-carrageenan in deionised distilled water, then heating the solution to 90?C with intermediate vortexing. They cooled the mixture to room temperature and placed a droplet in a fibre puller between two glass rods. When the droplet was partially dry, they stretched it to 2-3mm in length. They immersed the fibres in a solution of curcumin dissolved in isopropanol and water (curcumin is not water soluble) for three days. When they added water, they found that the fibres released the curcumin rapidly.

Peter Wilde, an expert in food materials, particularly colloids and interfacial systems, at the Institute of Food Research in Norwich, UK, is concerned that the release rate is rapid. ’This means that the fibres will have to be stored in a dry state, so will not be suitable for foods or nutraceuticals with any significant water activity,’ he says. If the release could be delayed, he says the system could potentially deliver active forms of curcumin to the duodenum and enhance bioavailability.

Tamsin Phillips