Recent Status of Deep Eutectic Solvents as Alternate Solvents in Processing of Coffee, Coffee by Products and Coffee Spent for Bioactive Constituents and Their Analysis

Coffee is one of the largest consumed beverage throughout the globe and manufactured methodically in the plantation industry. This review discusses the results of research studies using deep eutectic solvents (DES), as alternate green solvents in the processing of bioactive phytochemicals from coffee, coffee by products, spent coffee spent grounds (SCG). DESs are formed as uniform liquids by mixing hydrogen bond donor and hydrogen bond acceptor. These are also called as NADES, when these are produced from the primary metabolites. These are considered as green solvents for the last one decade, as these are safe, biodegradable and eco-friendly, when compared to conventional organic solvents. Their versatility is good, as these are useful in different processing techniques. Analyses of the composition of the constituents in DES extracts are reported. This review describes the effect of different parameters of extraction. Periods of processing are reduced. Solvent usage is decreased. Selected modern techniques are reported for exclusive separation of phytochemicals owing to the adaptable nature of DES/NADES. DES/NADES are being used during the valorization of coffee, coffee by-products, and SCG as alternate green solvents for different purposes. The NADES extracts are useful in food, biomedical, pharmaceutical and cosmetic industries.