Valorization of waste lavender residue from the essential oil industry for production of rosmarinic acid - a study on the solid-liquid extraction

The possibility for valorization of the waste lavender residue from the essential oil industry via solvent extraction was studied. The plant residue of Lavandula angustifolia, from which the lavender oil is extracted through steam distillation, contains Key Biologically Active Components (KBAC) such as: rosmarinic acid, caffeic acid, luteolin. The feasibility of the solvent extraction for their isolation was assessed by comparison of the kinetics and equilibrium of extraction of KBAC from spent and raw plant material (collected from the same batch before the steam distillation) using different solvent compositions. The parameters of the extraction process were experimentally and numerically optimized. To determine the most efficient solvent, two pure and two mixed solvents were tested: pure water, 99.9 % ethanol and their mixtures - (40 % and 60 % ethanol). Using 40 % ethanol as extraction solvent resulted in maximum recovery of KBAC. A mathematical model for the solid-liquid extraction from lavender materials was developed. The values of the model parameters were determined using the Regular regime method. A four-parameter empirical model for prediction of the effective diffusivity, Deff, was also applied. The model adequacy was experimentally verified. Based on the theoretical and experimental results KBAC recovery the following extraction conditions were recommended: extraction time - 30 min, temperature - 30 °C, liquid-solid ratio - 0,01 m3 kg- and 40 % ethanol as an extraction solvent.

Subjects

essential oil

kinetics

lavender

modeling

rosmarinic acid

solid-liquid extraction

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Valorization of waste lavender residue from the essential oil industry for production of rosmarinic acid - a study on the solid-liquid extraction