Obtenção de extrato de alecrim (Rosmarinus officinalis) por extração supercritica : determinação do rendimento global, de parametros cineticos e de equilibrio e outras variaveis do processo. / Recovery of the extract from rosemary (Rosmarinus officinalis) by supercritical extraction : determination of the global yield, kinetic and equilibrium parameters and other process variables.

AUTOR(ES)

Raul Nunes de Carvalho Junior

DATA DE PUBLICAÇÃO

2004

RESUMO

In this work the supercritical extraction from rosemary (Rosmarinus officinalis) using CO2 as solvent was studied, for the determination of the global yield isotherms, overall extraction curves and antioxidant activity. The phase equilibrium for the system rosemary + CO2 was studied. For the global yield isotherms the parameters studied were: pressure and temperature, from 100 to 300 bar and 30 and 40 °C, respectively. Particles from 24 to 48 mesh were used. The amount of raw material used in each assay was of 10 grams. Solvent flow rate was of 8,3 × 10-5 kg/s. For each experimental condition the assays were performed in duplicates. The experiments for the determination of the overall extraction curves were performed at 300 bar pressure and 40 °C temperature, in two supercritical extraction units with different ratios between bed height/diameter: 0.67; 1.35; 2.8; 5.6 and 8.4. The compounds of the extracts were quantified by gas chromatography, using the external standard method. The quantification of the phenolic diterpenes (carnosoic acid and rosmarinic acid) was done by UV/Visible spectrophotometer. The antioxidant activity was determined through a coupled reaction of beta-carotene and linoleic acid. The maximum global yield was of 5% (in dry basis), obtained at 40 °C temperature and 300 bar pressure. The main detected compounds were camphor and 1,8-cineol. The results were compared to those of organic solvent extraction (ethanol and hexane) and hydrodistillation. The antioxidant activity varied from 80% for the extracts obtained at 150 bar and 30 °C to 95% for the extracts obtained at 300 bar and 40 °C. The mathematical models of Crank, Sovová, Goto et al., Empiric, Tan &Liou and Martínez et al. were applied to experimental data in order to study the influence of process parameters on the extraction kinetics. The phase equilibrium experimental measures at high pressure were performed in a high pressure cell with variable volume, using the synthetic static method. The experiments were done for the isotherm of 313,15 K. The phase transitions were visually identified as bubble and cloud points.

ASSUNTO(S)

rosmarinus officinalis process extração com fluido supercritico phase equilibria antioxidant activity parameters supercritical extraction global yield

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