Pressurized Organic Solvent Extraction with On-line Particle Formation by Supercritical Anti Solvent Processes

Abstract

In this work, anovel on-line process for pressurised hot organic solvent extraction of antio xidants from plantsas well as precip itation of the extract with or without a carrier material in one step was developed. This process has been called OEPO,Organic solvent Ext raction and On-line particle formation. With this process, different products with a very low residual organic solvent concentration (< 50 ppm) can be obtained by the use of supercritical CO2 as anti solvent for solvent elimination.OEPO process consists of hyphenated Pressurized Liquid Extraction (PLE)-Supercritical Anti So lvent (SAS) precipitation, PLE-SAS co-p recipitat ion and PLE-Supercritical Fluid Ext raction of Emulsions (SFEE). OEPO process was successfully developed using Brazilian g inseng roots (Pfa ffiaglomerata)as a model case using ethyl acetate as extracting solvent. Results were co mpared, in terms of antio xidant activity o r mo rphology, with the ones obtained by each process separately.In addition, an optimizat ion study for antio xidants recovery was performed using ethyl acetate as extracting solvent during PLE process. Optimu m PLE extracts were produced under moderate extraction temperature (373 K) and high static extraction t ime (15 min). Under this condition an ext raction yield o f 1% (d ry basis, d.b.) and an antioxidant activity of 53% are obtained, wh ich was appro ximately 14% higherthan that observed after PLE-SAS p recipitation and after SAS precipitation performed in two steps (step one - PLE ext raction; step two - SAS precipitation by the use of the ext ract solution produced by step one stored).Similar behavior (hyphenated process producing similar p roducts than the two step process done separately) was observed for PLE-SAS co-precip itation and PLE-SFEE indicating that the OEPO process developed in this work can be considered as a suitable and p ro mising process to obtain, in only one step, different products (precipitated extract, co-precipitated extract or encapsulated extract in suspension), direct ly fro m plant materials.