Valorization of spent coffee grounds - A new approach

It is established that from well selected spent coffee grounds by water extraction and subsequent extract nanofiltration one can obtain valuable products as permeate and retentate fractions. The obtained permeate is of high caffeine concentration and is potentially applicable in soft and energy drinks production. The retentate has main characteristics (antioxidants concentration, caffeine content and browning index) suitable for its application as coffee drink or ingredient in food technologies. The conditions of the two processes allowing such separation are described and discussed: water/spent coffee grounds ratio, temperature and duration of extraction; membrane, pressure, modes of filtration and degree of feed volume reduction. The results obtained outline the elements of a new approach for valorization of spent coffee grounds avoiding the permeate treatment to powdered caffeine and extending the area of retentate applicability. The study encourages further investigations for practical realization of the approach.