Supercritical gas fluids (highly condensed gases) have been used for over a century. Recently, they have been used to produce standardized botanical extracts.
In March 2002, U.S. Nutraceuticals LLC completed a new supercritical fluid extraction facility at the company's headquarters in Eustis, Fla.
Every gas has its own Critical Pressure (Pc) and Critical Temperature (Tc). When a gas is compressed above its Pc and Tc, it becomes a dense gas rather than a liquid. It is in a supercritical state and is called a supercritical fluid. For example, carbon dioxide gas has a Pc of some 73 bar (about 73 atmospheres or 1059 psi) and a Tc of 31°C (about 88°F.). It becomes supercritical carbon dioxide when compressed above 73 bar while the temperature is kept above 31°C.
Supercritical fluids have very desirable and unique properties when used as solvents. They possess the diffusivity properties of gases, which allow them to easily permeate finely ground solids. However, as dense gases, they achieve the densities of fluids, which enhances their use as extraction solvents. Supercritical carbon dioxide often is used at densities around 0.8 to 0.9 wgt/vol similar to that of common vegetable cooking oils.
As a supercritical fluid passes through ground raw material in a high-pressure vessel (extractor), it penetrates and dissolves selective compounds. The gas fluid is then passed to a second vessel (separator) where the pressure and temperature are reduced, causing the dissolved compounds to be released in absolutely pure condition. By passing the loaded gas fluid through a series of separators at successively lower pressures and temperatures, different extract fractions are precipitated.
Pure, Powerful, Pioneering
U.S. Nutraceuticals' proprietary process, called SuPure CO2®, maximizes supercritical fluid extraction parameters to optimize the efficient recovery of specific active ingredients from a specific botanical. Heavy molecular weight compounds, such as phytosterols, can be extracted and recovered concurrently with lighter, more delicate volatile oils. According to Tony Evans, Ph.D., vice president of product development, this ability to manipulate various botanicals is unparalleled. â€œThe core beauty of the SuPure CO2 process is that we can target a specific phyto-nutrient or a full spectrum of the botanical without the use of undesirable organic solvents.â€? Two of the company's latest breakthroughs include St. John's wort extract (standardized to a 30% total hyperforin content), and valerian root extract containing over 8% valerenic acids. Other company ingredients include antioxidant-rich coffee oils, fractionated ginger oleoresins, high-sterol saw palmetto extracts and astaxanthin and lutein recoveries.
U.S. Nutraceuticals founder and CEO, Fred Gregg Jr., puts forth a clear and aggressive vision. "Supercritical fluid extraction technology is wonderfully diverse in its applications and delivery of exceptionally pure finished ingredients. Our new supercritical facility is an integral part of our initiative to be the premiere manufacturer of botanically derived nutraceutical extracts in the world."