Supercritical Carbon Dioxide

A faint herbal aroma wafts among the gargantuan metal tanks and clanking machinery. The scent comes from an Indian seed, neem, whose extracts are used as a biocide. And Altex, S.A., a company near Valencia, Spain, is using supercritical carbon dioxide to extract the oil from the seed.

Extracting compounds from agricultural products is common practice; decaffeinated coffee and cocoa butter from cocoa powder are two of the most familiar examples. But many solvents used to catalyze these separations contain harsh chemicals and may taint part of the original product, preventing its future use in food applications.

One promising solution to this problem is the use of supercritical carbon dioxide, which has been subjected to high pressure and temperatures such that its density becomes that of a liquid, while it retains the mobility of a gas. That flow, tweaked by temperature, pressure, and the addition of small amounts of other materials such as water, can be directed to latch onto specific types of molecules, pull them away from the rest of the material, and then deposit them elsewhere following a decrease in pressure. The use of supercritical carbon dioxide can, for instance, separate out cocoa butter and leave behind a pure cocoa powder residue. The carbon dioxide is then recovered and reused.

Engineers at the research center Ainia developed a system for optimizing supercritical carbon dioxide for food and developed methods for specific food products. The center has also spun this technology off and created the company (Altex, S.A.), which operates one of the largest facilities for supercritical carbon dioxide extraction in the world. Altex works with customers around the world, including France, the UK, and Australia, to develop systems to extract plant-based compounds, including cocoa powder, valerian root extract, and neem. One project involved developing a proprietary technique for a company interested in eliminating a chemical component in cork, to prevent cork from contaminating wine.

“Our flexibility means that we can offer these services to food and beverage companies, and also for cosmetics and pharmaceuticals,” says Antonio Tornero, Altex general manager. “There is nothing we can do to damage the original materials.”.

Extract from an article published in the magazine Technology Review

www.technologyreview.com/microsites/spain

Supercritical Carbon Dioxide

A faint herbal aroma wafts among the gargantuan metal tanks and clanking machinery. The scent comes from an Indian seed, neem, whose extracts are used as a biocide. And Altex, S.A., a company near Valencia, Spain, is using supercritical carbon dioxide to extract the oil from the seed.

Extracting compounds from agricultural products is common practice; decaffeinated coffee and cocoa butter from cocoa powder are two of the most familiar examples. But many solvents used to catalyze these separations contain harsh chemicals and may taint part of the original product, preventing its future use in food applications.

One promising solution to this problem is the use of supercritical carbon dioxide, which has been subjected to high pressure and temperatures such that its density becomes that of a liquid, while it retains the mobility of a gas. That flow, tweaked by temperature, pressure, and the addition of small amounts of other materials such as water, can be directed to latch onto specific types of molecules, pull them away from the rest of the material, and then deposit them elsewhere following a decrease in pressure. The use of supercritical carbon dioxide can, for instance, separate out cocoa butter and leave behind a pure cocoa powder residue. The carbon dioxide is then recovered and reused.

Engineers at the research center Ainia developed a system for optimizing supercritical carbon dioxide for food and developed methods for specific food products. The center has also spun this technology off and created the company (Altex, S.A.), which operates one of the largest facilities for supercritical carbon dioxide extraction in the world. Altex works with customers around the world, including France, the UK, and Australia, to develop systems to extract plant-based compounds, including cocoa powder, valerian root extract, and neem. One project involved developing a proprietary technique for a company interested in eliminating a chemical component in cork, to prevent cork from contaminating wine.

“Our flexibility means that we can offer these services to food and beverage companies, and also for cosmetics and pharmaceuticals,” says Antonio Tornero, Altex general manager. “There is nothing we can do to damage the original materials.”.

Extract from an article published in the magazine Technology Review

www.technologyreview.com/microsites/spain