(744d) Sustainable Soluble Coffee Production Using Dynamic Membrane Processes

A study, in partnership with Nestlé Beverage USA, and U.S. Environmental Protection Agency, is underway to improve the sustainability profile for the manufacture of instant (soluble) coffee products. In this study, the application of membrane processes in the pre-concentration of coffee extract prior to spray/freeze drying has been found to be a promising alternative to energy-intensive separation methods such as evaporation. Such approach opens opportunities in the intensification of soluble coffee production in terms of energy-efficiency, water recovery, and waste reduction, thereby reducing the carbon footprint of the overall operations. In addition, the use of a novel dynamic vibratory separation process to address the limitations of traditional crossflow filtration, by imparting shear at the membrane surface, reducing gel formation and fouling, and improving flux was investigated. In this study, we highlight the benefits and limitations of the technology, and how laboratory investigations help guide industrial use and scale-up considerations; and the overall assessment of environmental impacts. Using reconstituted coffee extract solutions, we tested and screened various types of membranes to determine their performance in concentrating the samples. Parametric studies were also conducted in order to determine the effects of varying feed concentrations, transmembrane pressure, and surface shear (vibrational displacement) on permeate flux, and selectivity of filtration in terms of organic/inorganic rejection efficiencies. Scale-up trials from laboratory scale system were correlated to estimate design parameters for a commercial membrane filtration unit. Different cases involving the integration of membrane processes are compared with the conventional evaporative pre-concentration of coffee extract. As criteria for sustainability, the potential energy savings, operating costs reduction, economic feasibility, and resulting life cycle emissions profiles of the scaled-up operation are also presented. As a promising area for further investigation, our research shows opportunities in making soluble coffee and similar powdered beverage manufacturing operations greener.