No abstract

The increasing demand for high-quality products and economically and environmentally friendly technologies, as well as restrictive legislative actions, has stimulated scientific research on the extraction, purification and identification of bioactive compounds from natural sources. Pomegranate (Punica granatum L.) is commonly used in traditional medicine due to its pharmacological properties, such as its anti-inflammatory, antihepatotoxicity, anti-lipoperoxidation, antidiabetic, anti-cancer and antimicrobial activities. The use of industrial residues as sources of bioactive compounds has emerged as an economically viable solution to the problem of solid waste treatment. In this context, this work aimed to evaluate the SC-CO 2 extraction of polyphenols from pomegranate leaves, evaluating the influence of temperature (40 and 50°C) and pressure (10-30 MPa) on extraction yield (EY), total phenolic content (TPC), antioxidant activity (AA) and the cost of manufacturing (COM) of the extracts. Principal component analysis (PCA) was used to reduce the dimensionality of multivariate data, making the visualization more straightforward and manageable. A high EY and TPC and low COM were obtained at the most effective operational conditions of 50°C and 30 MPa. The lack of correlation between EY-AA and TPC-AA indicated the coextraction of non-phenolic compounds. This assumption was corroborated by GC-MS analysis, which showed high levels of eicosanol, squalene, linoleic acid and tocols. Even though SC-CO 2 extraction resulted in a high TPC (257-389 mg.g -1 ) compared to the literature data, the low EY (0.21-0.67 %) and non-phenolic presence suggest that SC-CO 2 extraction may be a good purification pretreatment for the removal of non-polyphenolic compounds prior to further polyphenol extraction.

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 CO 2 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.