Valorization of solid wastes from essential oil industry

Natural antioxidants have attracted attention owing to their potential good effects in health. On the other hand, valorization of residues is an opportunity to obtain profit in a sustainable way. In this work antioxidants were obtained from residues of rosemary after extraction of essential oil using steam distillation, hydrodistillation and Solvent Free Microwave Extraction (SFME). A solvent extraction with ethanol was used to obtain the antioxidants. Then a comparison of the results is made in order to know which process delivers a residue with higher concentration of antioxidants. Mass transfer rates of antioxidants from leaves are increased as a result of the previous extraction of essential oils. Higher yields and rates of extract from leaves after SFME have been observed. (C) 2010 Elsevier Ltd. All rights reserved.