Assessing of the most appropriate biotechnological strategy on the recovery of antioxidants from beet wastes by applying the life cycle assessment (LCA) methodology

The valorization of agro-industrial waste streams and residues for the production of antioxidant compounds is a good strategy for circular economy approaches. However, to demonstrate its suitability and operational feasibility, it is necessary to develop environmental assessments to ensure the effectiveness of the production strategy. In this sense, a large-scale simulation has been developed, obtaining ten different scenarios in which both leaves and steam residues are used as process inputs, and five different extraction techniques are applied, both conventional: Soxhlet and maceration, and emerging technologies: ultrasonic assisted extraction (UAE), supercritical fluid extraction (SFE) and pressurized liquid extraction, (PLE). Environmental results have shown that SFE and PLE technologies have the lowest environmental burdens, while UAE has the worst profile due to high energy demand. Electricity could be considered as the main hotspot with the highest impact, followed by steam requirements and the use of extraction solvent. To improve the environmental profile, sensitivity analyses were performed, considering the use of renewable resources for the production of the energy requirements and the selection of the extraction solvent. Although significant improvements were obtained when electricity and steam production is based on hydropower and waste incineration, the environmental profile did not improve when considering ethanol: water mixture or hexane for extraction. Future research should focus on reducing energy requirements and optimizing the solvent dosage for the extraction process.