(20e) Solvent Optimization for Extraction of High Commercial Value Chemicals from Food Waste

The global challenge of food waste (FW) is evidenced by the fact that approximately a third of global food production (i.e., 1.3 billion tons) ends up as waste. Traditional FW treatment methods, such as disposal into landfills and composting, are environmentally unfriendly. Intensive exploration of other methods that selectively utilize the diverse composition of FW to high commercial value chemicals is a key to alleviating this challenge. Extraction of antioxidant and antimicrobial activity providing chemicals (flavonoids, phenolic acids, etc.) from FW feedstocks is one such economically lucrative option to valorize FW. The choice of the solvent has been identified as a critical parameter affecting the efficiency of extraction. However, there is an insufficient fundamental understanding of the solvent selection process for FW extraction applications, with ethanol and methanol being a common choice. This study directly addresses this issue by focusing on solvent selection for enhancing the extraction efficiency of various phenolic compounds from FW. In silico screening using ADF-COSMO-RS is conducted to identify solvents providing high solubilities for the target compounds. These predictions reveal more than 150 possible solvents provide higher solubilities than ethanol and methanol, with up to 15-fold enhancements. Analysis of sigma profiles reveals the underlying physicochemical interactions behind the enhanced solubility. Nine promising environmentally “green” solvents are then shortlisted. Experimental investigations of the solubility of representative phenolics in the selected solvents via HPLC show reasonable agreement with model predictions. Further, we also propose the replacement of high solubility, toxic solvents with green solvents. This comprehensive study provides a general methodology for solvent selection and generates new insights into FW extraction.