Concentration of coffee extract using nanofiltration membranes

• Concentration coffee extract to a high total solid was conducted by nanofiltration.
• The maximum concentration and solid loss was evaluated.
• The capability of using nanofiltration for coffee concentration is demonstrated.

The potential of using nanofiltration (NF) membranes to concentrate coffee extract was investigated in this study. Six commercial NF membranes were screened using pure water and coffee extract tests. Ultimately NF-2 NF membrane from SEPRO was selected to evaluate the concentration of coffee extracts due to its better performance. A commercial spiral wound NF-2 membrane element was used to evaluate membrane performance at 40 °C and 28 and 40 bar. The theoretical maximum concentrations that can be achieved at 28 and 40 bar were 35% and 39%, respectively, based on model regression. Mass balances were calculated to estimate solid loss during the concentration process. At the two operation conditions, the solid losses are 2.8% and 3.3% over the processes. Overall, it is concluded that NF membranes are capable to concentrate coffee extract to a certain level and have a potential to partially replace conventionally evaporation process.