This paper reports experimental data on the pressurized liquid extraction of caffeine from green coffee beans and green tea leaves using ethyl lactate (ethyl 2-hydroxy-propanoate). This solvent is a new bio-renewable agrochemical solvent, naturally produced by fermentation from corn derived feedstock, which has been recently considered as a very suitable and environmental benign solvent for food industrial applications. Static extraction assays (one step during 10 min) were carried out in an Accelerated solvent extraction (ASE) system at three different extraction temperatures, namely 100, 150 and 200 C. Extraction yield and caffeine recovery were determined and compared with those obtained when using other liquid solvents, such as ethyl acetate or ethanol. High recovery of caffeine (≈60%) was found in the extracts produced using ethyl lactate, which demonstrates the potential use of this green solvent for the extraction of caffeine from different vegetable sources.

The authors gratefully acknowledge the financial support from the Ministerio de Ciencia e Innovación of Spain (joined project Spain-Portugal, PT2009-0010) and the financial support from the Conselho de Reitores das Universidades Portuguesas (CRUP) – Integrated project Portugal – Spain, N◦ E-95/10. P. Luna and D. Villanueva acknowledges, respectively, the postdoctoral and predoctoral contract (JAE) given by the Consejo Superior de Investigaciones Científicas (CSIC) of Spain. M. S. Manic is thankful to Fundação para a Ciência e Tecnologia – Portugal for a doctoral fellowship (SFRH/BD/45323/2008).