Chemical characterization and bioethanol extraction from peel of ‘Valencia’ oranges grown in Rioverde, San Luis Potosí-Mexico

Abstract

Bioethanol extraction is one of the most important challenges in the generation of environmentally friendly biofuels. The search for matrices to allow producing high levels of these fuels represents an area of study in technological innovation, where agro-industrial waste can be considered an alternative for the production of second-generation bioethanol, thus avoiding the increase of waste in landfills and providing added value to agro-industrial byproducts. In this work, we evaluated the chemical composition of oranges grown in the Rioverde, San Luis Potosí region. The values obtained per 100 g of peel were: 2.4 mg total phenols (expressed as Gallic acid equivalent, quantified by Folin-Ciocalteu); 0.038 mg of total flavonoids (expressed as quercetin equivalent, quantified by potassium acetate); 2.9 g glucose; 2.3 g fructose; 0.9 g saccharose; and 14.25 mg ascorbic acid, quantified by HPLC. Finally, the 20 mL of 90 % ethanol obtained by anaerobic fermentation of 2 kg peel using Saccharomyces cerevisiae produced enough energy to power a thermomotor. These results provide important evidence supporting the feasibility of using orange peel to produce biofuel or food additives.