Rosemary is one of the most appreciated natural sources for bioactive compounds with different activities such as antioxidant, antimicrobial or anticarcinogenic. Antioxidant activity has been associated to some of its components, among them, phenolic diterpenes such as carnosic acid, carnosol and rosmarinic acid. A careful selection of the extraction process together with the optimization of the extraction conditions, are of high importance to obtain rosemary extracts with high bioactivity. Among the different extraction processes, supercritical fluid extraction (SFE) and pressurized hot water extraction (PHWE) have demonstrated to be the most selective and environmental friendly techniques. However, extracts obtained by these processes usually require a drying step (freeze or hot drying step) which is both energy and time consuming. In this work, a new process combining PHWE and powder formation on-line (water extraction and particle formation on-line process, WEPO®) has been developed to obtain dry antioxidant powder from rosemary leaves in one step. In this process, parameters related to the extraction efficiency and selectivity (water flow rate and temperature) as well as parameters involving spray stability and powder formation have been considered at the same time. The obtained extracts have been evaluated in terms of their antioxidant activity using the DPPH method. Finally, in order to assess the viability and environmental impact of the new process, a comparison with other green processes used for antioxidant extraction from rosemary leaves such as SFE and PHWE (both followed by a freeze drying step) has been performed in terms of Life Cycle Assessment (LCA). Moreover, a sensitivity analysis of the LCA has been carried out to study the different environmental impact between the processes whether they are employed in different countries.

This work was supported by AGL2008-05108-C03-01 (Ministerio de Educación y Ciencia), CSD2007-00063 FUN-CFOOD (Programa CONSOLIDER-INGENIO 2010), and S-0505/AGR/000153 (Comunidad Autónoma de Madrid) projects. C.T. acknowledges the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS, 2006-1346); the Swedish Research Council (VR, 2006-4084); and the Swedish Foundation for Strategic Research (SSF, 2005:0073/13, RMA08-0044). M.C-P. thanks MICINN for her “Juan de la Cierva” contract.

Trabajo presentado al 10th International Symposium on Supercritical Fluids celebrado en San Francisco (US) del 13 al 16 de mayo de 2012.

Peer Reviewed