How SCFE Retains the Nutritional Benefits of Oleoresins

A mixture of spices and resins that occurs naturally in plants, oleoresins are sensitive to heat, light, and oxidation. In other words, their chemical composition changes when exposed to these three elements. Methods used for oleoresin extraction as well as oleoresin oil extraction, therefore, must take care not to expose the raw material to such elements.

Supercritical fluid extraction (SCFE) uses a supercritical fluid (SCF) which:

@ Selectively dissolves the oleoresin from raw material at high pressure; and

@ Throws it out of solution at low pressure.

When carbon dioxide (CO2) is used as the SCF, the process temperature is low because the critical temperature of CO2 is 31.1 deg-Celsius which is around the room temperature. This prevents the oleoresin from getting exposed to heat and oxidation.

Oleoresins can provide their immense health benefits only if available in their pure form. By preventing their heat-related distortion, CO2 SCFE retains their health benefits. Producers, therefore, prefer CO2 SCFE for oleoresin extraction and oleoresin oil extraction.

Speaking of medicinal value of oleoresins, these are anti-inflammatory and antioxidant which makes them capable to:

@ Reduce the possibility of developing cancer.

@ Counter flatulence.

@ Ward off infections in the urinary tract.

@ Fight rheumatism.

@ Resist muscle and joint ache.

@ Lower digestive issues.

@ Minimize the possibility of diarrea.

An SCF is a fluid that has its:

@ Pressure above its critical pressure; and

@ Temperature above its critical temperature.

In this state, its properties can be:

@ Similar to that of its liquid state;

@ Resemble that of its gaseous state; or

@ Somewhere in between.

For example, the:

@ Density of the SCF is high, similar to that of its liquid state; and

@ Viscosity and surface tension are low, as that of its gaseous state.

Higher density enables it to dissolve more of the required compound (called target molecule which is oleoresin in this case). Increasing pressure increases its density whereby its dissolution power also increases. By carefully controlling pressure, the SCF can be made to dissolve only the required oleoresin. Very little of other compounds from the raw material get dissolved. This maintains the purity of the separated product and is another reason why producers prefer SCFE for oleoresin extraction and oleoresin oil extraction. At low pressure, the dissolved oleoresin precipitates out from the SCF and is collected.

Low viscosity and surface tension enable the SCF to penetrate deeper into the raw material and achieve greater mass transfer rates. Both these factors improve the yield of extraction and is another factor promoting the use of SCFE.