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  • Extraction and bioprocessing with supercritical fluids
    Publication . Coelho, Jose; Trucillo, Paolo; Nobre, Beatriz; Palavra, António; Campardelli, Roberta; Reverchon, Ernesto
    Supercritical fluid (SCF) technologies have emerged as a real alternative to various natural product extraction processes and pharmaceutical production to obtain micronized particles, coprecipitates, nanocomposite polymer structures and liposomes, in addition to other increasingly larger applications described in literature. In the present work, a brief literature review of the application of supercritical fluid extraction (SFE) is presented. This is evidenced by several publications and patents, contributions from several countries and the increase of industries around the world dedicated to this technique. Next, we aim to focus the analysis of SFE on a review of the literature applied to microalgae as a substitute primitive feedstock due to its high growth rate, valuable biologically active lipophilic substances, and photosynthetic efficiency without competition with food sources or needs of arable lands. We finally discussing an SCF bioprocess with a very new perspective for liposome production focalized on its potential at industrial scale.
  • Supercritical CO2 extracts and volatile oil of basil (Ocimum basilicum L.) comparison with conventional methods
    Publication . Coelho, Jose; Veiga, Jerson; Karmali, Amin; Nicolai, Marisa; Reis, Catarina; P. Nobre, B.; Palavra, António
    Interest in new products from aromatic plants as medical and nutritional compounds is increasing. The aim of this work was to apply different extraction methods, including the use of supercritical carbon dioxide extraction, and to test the antioxidant activity of basil (Ocimum basilicum L.) extracts. In vitro efficacy assessments were performed using enzymatic assays. Essential oil obtained by hydrodistillation and volatile oil obtained from supercritical fluid extraction were analyzed by gas chromatography to quantify components. The total phenolic content in the extracts ranged from 35.5 +/- 2.9 to 85.3 +/- 8.6 mg of gallic acid equivalents and the total flavonoid content ranged from 35.5 +/- 2.9 to 93.3 +/- 3.9 micromole catechin equivalents per gram of dry weight of extract. All the extracts showed an antioxidant activity with 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), and the reducing power test. Extracts obtained from methanol had a higher antioxidant capacity per the DPPH test results (IC50 = 3.05 +/- 0.36 mg/mL) and the reducing power test assay 306.8 +/- 21.8 mol of trolox equivalents per gram of extract (TE/g) compared with ethanolic or supercritical fluid extracts. However, using the ABTS assay, the extract obtained by supercritical fluid extraction had a higher antioxidant capacity with an IC50 of 1.74 +/- 0.05 mg/mL. Finally, the examined extracts showed practically no acetylcholinesterase (AChE) inhibitory capacity and a slight inhibitory activity against tyrosinase.