Oil recovery from defective coffee beans using pressurized fluid extraction followed by pyrolysis of the residual biomass: Sustainable process with zero waste

Abstract

In this study, oil was extracted from various types of defective coffee beans using pressurized fluids. After extraction using solvents, the residual biomass was used as a raw material in a pyrolysis process to obtain bio-oil. Palmitic and linoleic fatty acids were the predominant components of the obtained oils. When n-propane was used for pressurized extraction, the yield of coffee bean oil and the phytosterols and tocopherol content increased. The highest levels were found in oil extracted from green coffee. Increasing the solvent flow rates improved the yield of the extracted oil, while increasing the temperature had the opposite effect. Higher temperatures and pressure resulted in higher levels of phytosterols. Low extraction temperatures resulted in an oil with a higher tocopherol content. The main product of biomass pyrolysis was a bio-oil rich in caffeine and phenolic compounds. This is an effective strategy for the clean and sustainable production of bio-oil.