Bio-based molecular imprinted polymers for separation and purification of chlorogenic acid extracted from food waste

Abstract

Food waste is a profound challenge as 17% of global food production (i.e., 931 million tons) ends up as waste yearly. A cost-effective strategy is the extraction of high-value phenolic acids from food waste, but their downstream purification is challenging owing to their similar chemical nature, high boiling points, and low concentrations in complex mixtures. Herein, we propose separating target phenolics using molecular imprinted polymers. The stability of the monomer-template complex during the synthesis is critical in optimizing the polymer selectivity and performance. COnductor like Screening MOdel for Real Solvents (COSMO-RS) and Hansen Solubility Parameters in Practice (HSPiP) computations were used to screen the interaction of 28 monomers and 13 porogenic solvents with chlorogenic acid as the target molecule. Experiments revealed that itaconic acid, the functional monomer, and tetrahydrofuran (THF), the synthesis solvent, provide the highest reported separation factor. The polymer exhibits superior selectivity towards chlorogenic acid in concentrated solutions of up to 1 mg/mL, and its high sensitivity to various functionalities enables the effective separation of all target phenolic acids. The polymer's performance was evaluated in different extraction solvents, and Fourier transform infrared (FTIR) studies revealed polymer–solvent interaction as the critical factor influencing its performance. The application of the polymer in purifying up to 92% chlorogenic acid from coffee beans and potato peel waste extractives is demonstrated, and its reusability is evaluated. In contrast to the current industrial purification methodology that produces mixtures, the proposed technology provides at least eleven times higher economic value and 95% less carbon emissions based on lab-scale techno-economic analysis.