Polyphenol extraction from olive leaves to show Chemical Engineering students the importance of revaluating residues while improving their hands-on experience

Abstract

The aim of this work was to try to implement a new laboratory class for Chemical Engineering students in which they could analyze how it is possible to revalue some organic residues. Concretely, the objective was to show them how to revalue olive leaves by extracting their polyphenols, since these leaves, being an abundant organic waste in Spain, were well-known by the students to whom this study was addressed. With the aim of improving student understanding of the basic Chemical Engineering concepts, two extraction techniques (solvent extraction process and ultrasound-assisted extraction) as well as their combination were investigated during the class. In addition, the effect that different pre-treatments had on polyphenol extraction efficiency was also studied to show students how important research is before fine-tuning an industrial process. To do this, students were divided into working groups to carry out polyphenol extraction under different experimental conditions. Ultimately, student groups compared and discussed the efficiency of the different employed extraction techniques. Likewise, students were surveyed to evaluate the suitability and training-usefulness of the proposed class. Obtained assignments revealed that it could be an interesting option to improve students’ hands-on experience while strengthening some theoretical concepts explained in the degree lectures.