Characteristics of Arabica and Robusta Spent Coffee Grounds Oil Extract with Different Solvents

Abstract

High coffee consumption contributes to waste, such as spent coffee grounds (SCG). SCG contains up to 20 % oil, with the main oil content being linoleic and palmitic fatty acids. So, SCG has the potential to be used in valuable products. This study aims to characterise Arabica and Robusta SCG oil using maceration methods with different solvents (hexane, ethanol, and petroleum benzene) to obtain maximum coffee oil as an alternative. Arabica and Robusta SCG characterisation comprises the composition content, oil yield, fatty acid profile, and viscosity. The results showed that Arabica SCG oil yield was higher than Robusta, with hexane becoming the most efficient solvent to extract the oil, with 28,87% and 25,57%, respectively. The lowest free fatty acid (FFA) found in Arabica SCG oil extract using hexane is 1,95%, which consists of palmitic acid (9.41%), linoleic acid (5.37%), and stearic acid (4.7%). The highest viscosity is Arabica SCG oil extract using hexane, which is caused by the large amount of long-chain fatty acids extracted by the solvent, such as palmitic acid and linoleic acid. The FFA content of Arabica SCG oil extract using hexane has the potential to be edible oil (cooking oil) and biodiesel.