Application of a screening design to recover phytochemicals from spent coffee grounds

This study investigates the recovery of phytochemicals from SCG. The aim is to estimate the effect of a wide number of variables on the amount of caffeine and phytochemicals recovered with a green method for water-soluble compounds that do not require the use of organic solvents. In the first part, we use a Plackett–Burman design to estimate which extraction parameters have most influence on phytochemical recovery. In the second part, we test only the significant factors and caffeine and chlorogenic acids were quantified using HPLC-DAD. The first part of the study showed that the temperature and the type of SCG can significantly affect phytochemical recovery. In the second part, four temperatures and two types of SCG were tested and thehigher concentrations of caffeine and chlorogenic acids were found at 110 °C. Furthermore, a significant effect was found for type of SCG with significantly higher phytochemical recovery for the French Press compared to the Espresso method. The mild temperature, combined with the use of water as a solvent makes the recovery system both green and low-cost.