Instant controlled pressure drop combined to ultrasounds as innovative extraction process combination: fundamental aspects

To entirely recover and value orange peels by extracting both essential oils and antioxidant compounds, hydrodistillation and standard solvent extraction are usually used. These treatments are known as long, fastidious, and energy-consuming processes mainly because of a low diffusivity coupled with a low starting accessibility. Various innovative processes were recently proposed, studied and optimized. They could have their own advantages. By analyzing the fundamental aspects of different processes, it was possible to recognize the limiting phenomena. Therefor, combining adequate innovative processes intensified the whole operation. This will increase heat and mass transfers; both process performance and extract quality could be dramatically improved. DIC (Detente InstantaneeContro lee), instant controlled pressure-drop treatment enhances autovaporization, which results in an expansion of the sample. The autovaporization enables a direct extraction of essential oils simultaneously triggering expansion, which enhances the availability of some molecules and also increases solvent diffusivity within the plant matrix. Ultrasound extraction process is fast in comparison with standard methods, thanks to a greater contact surface area between solid and liquid phase. It was possible to compare the effect of ultrasound-assisted extraction to standard solvent extraction in terms of fundamental aspects, highlighted with a former experimental study. Fundamentals enabled the study and comprehension of the extraction modelling. As an example, orange peel extraction has been studied. In order to achieve innovative extraction, we combined and associated these two techniques. We carry outthe treatment by DIC to extract the essential oils and at the same time to obtain a textured vegetal material. Followed by ultrasound assisted solvent extraction, a great intensification of antioxidants extraction is generated. It was possible to compare the effect of ultrasound assisted extraction to standard solvent extraction both achieved on dried orange peels as raw material and DIC treated material. Combining DIC to ultrasounds enabled enhancing yields and extraction kinetics of antioxidant. (C) 2012 Published by Elsevier Ltd.