Multi-objective optimization tool for ultrasound-assisted extraction including environmental impacts

Abstract

Enhancing the environmental performance of production processes is currently a major issue. To propose efficient processes both in terms of productivity and environmental impacts, it is necessary to develop multi-objective optimization tools. Such an approach was developed in this study for an ultrasound-assisted extraction process, aiming at valorizing antioxidant polyphenols from downgraded beetroot seeds (agri-food by-product). Environmental impacts of the process (assessed using LCA), as well as classical productivity indicators (extraction yield, antioxidant activity of the extract, energy consumption) were all predicted in function of the varied process parameters (extraction time, solvent composition, solvent/beetroot seeds ratio, ultrasound power density). The proposed multi-criteria optimization tool allowed to predict optimal operating conditions in function of specific constraints, such as maximization of extraction yield and/or minimization of extraction time, energy consumption and/or environmental impacts. Maximal polyphenols concentration (2.8g.L-1 GAE) and antioxidant activity (16.6mM TEAC) were obtained after 120min with 65% ethanol in the solvent, ultrasound power density of 667W.L-1, and ratio of 5mL.g-1. Ultrasounds assistance allowed extraction yield enhancement (up to 60%) of and process duration decrease (8 times), without degrading environmental performance. The original proposed methodology could easily be adapted for multi-criteria optimization of other processes.