Green coffee oil extraction: New trends and applications

Within the coffee industry, the need has arisen to generate different uses of the grain, due to the health impact generated by coffee on consumers, many studies have been carried out about its composition and its benefits thanks to antioxidants that are present in the bean. The lipid fraction of the bean is composed of fatty acids, sterols, diterpenes, tocopherols, and triglycerides, which influence the aroma and flavor of coffee. Coffee lipids are mostly distributed in the endosperm of the grain and only part is in the outer layer in the form of wax. Coffee beans contain between 7 and 17% total lipids, Arabica coffee has between 10.5 and 17.5% and Robusta coffee has between 8 and 10%. Cafestol and kahweol are diterpenes present in coffee oil, these lipids are interesting owing to their impact on human health. Cafestol is present in both species (Arabica and Robusta). However, kahweol is specifically presented in Arabica coffee. These are classified as pentacyclic diterpenes penta cyclic based on isoprene fusion (C5) to form a 20-carbon kauran skeleton. Kahweol differs from cafestol by a double link between C1 and C2. Both compounds have low light and heat stability. Evidence has been accumulated showing that cafestol, and kahweol have a relevant role as antioxidants, antitumor, chemoprotective, and anti-inflammatory effects. Green coffee oil has antioxidant compounds such as β-tocopherol (47.12 g/g), γ-tocopherol (2.63 g/g), and α-tocopherol (16.72 g/g). Therefore, the study of green coffee oil is relevant. Extraction and/ or isolation of the main functional compounds can be carried out by different methodologies such as the use of presses, solvent extraction, extraction with supercritical CO₂, microwave-assisted extraction, and extraction of pressurized liquid. There are studies in which the oil has been extracted and characterized, where these suggest that it has applications for the food industry and provides health benefits, due to its effectiveness in protecting oxidative stress through kahweol and cafestol that mainly act as antioxidants.