Using Ecoscale as a Metric to Evaluate the Extraction of Phenolic Compounds from Cashew Bagasse Using Subcritical Water

The production of bioproducts from agroindustrial residues using eco-friendly extraction techniques is a complex task that requires appropriate metrics to evaluate the sustainability of the methods employed. In this study, we turn to the Ecoscale metric, which applies penalty points based on safety in the process, solvent choice, cost, industrial availability, technical setup, and process temperature. Our objective was to evaluate the extraction of phenolic compounds from cashew apple bagasse using subcritical water extraction and compare it with other extraction methods using the Ecoscale metric. The experimental conditions included 15 MPa pressure, 120°C temperature, and a solvent-to-feed ratio of 15 mL g^-1, utilizing acidified water (pH 2 with citric acid) as the extraction solvent. Total phenolic compounds (TPC) were quantified using the Folin-Ciocalteu method. Comparative studies in the literature employed different extraction methods but followed the same TPC determination methodology. Results were normalized by the relative yield of TPC (% relative), with the highest experimental yield set at 100%. The data were then converted to a scale of 1 to 100, indicating higher values for more ecological methods. In this study, subcritical water extraction scored 95 on the Ecoscale, while the four comparative studies ranged between 36.75 and 65.39. The main penalties identified in comparative methods were organic solvents such as methanol and acetone and lower yields associated with conventional extraction methods like maceration. The Ecoscale assessment revealed that subcritical water extraction significantly outperformed other methods in terms of sustainability, emphasizing its potential to reduce environmental impact and promote eco-friendly practices in the bioproduct industry. These findings highlight the importance of the Ecoscale metric in the context of our research and stress the need for comprehensive sustainability metrics like it to guide the development and implementation of environmentally responsible extraction processes in the bioproduct industry.