Chemical Composition and Antioxidant Capacities of Four Mediterranean Industrial Essential Oils and Their Resultant Distilled Solid By-Products

The aim of this work is to chemically characterize and evaluate the antioxidant capacities of the essential oils and their resulting solid residues of four aromatic plants from the industrial distillation, including hyssop (Hyssopus officinalis L.), lavandin (Lavandula x intermedia var. Super), cotton lavender (Santolina chamaecyparissus L.), and winter savory (Satureja montana L.). In general, the different in vitro antioxidant assays showed that both the oil and the industrial residue extract of S. montana followed by the residue of S. chamaecyparissus are the best antioxidants, whereas the solid residue extracts of S. chamaecyparissus and H. officinalis show the highest copper and iron chelating capacities, respectively. Therefore, distilled solid residues might well constitute a viable and profitable source of natural antioxidants with a potential application in food and non-food products. Practical Applications: Solid residues from the industrial steam distillation of aromatic plants constitute an available and affordable source of phenolic compounds that can be used as natural and safe antioxidants, among others, in foodstuffs. Moreover, the exploitation of distilled plants constitutes a sustainable approach to reduce the residues generated every year from this industry, which results in environmental issues when they are not correctly managed.