2017 ASHS Annual Conference

The lipid fraction of coffee is a very complex mixture composed mainly of triacylglycerols, diacylglycerols, free fatty acids and phospholipids. In contrast to other vegetable oils, coffee oil has also a remarkably high content of unsaponifiable fraction, which consists mainly by terpenes and sterols. Although the lipid fraction accounts of around 15% of the mass of an Arabica coffee bean and contains a high concentration of several potentially bioactive compounds, which also affect the organoleptic properties of the coffee beverage, only a small number of studies have been published in this area. In this study we employed multinuclear and multidimensional NMR spectroscopy as a rapid and reliable tool for the quantitative analysis and the evaluation of the non-polar part of Coffea Arabica. A number of gradient-selected two-dimensional NMR techniques were applied for a systematic two-dimensional analysis of the various components in coffee oil. Quantification was achieved by integration of the appropriate diagnostic signals in the NMR spectra and using an internal standard as well as the ERETIC method. Our results indicate that multinuclear (¹H, ¹³C, ³¹P) NMR spectroscopy can be a valuable tool for the determination of several bioactive compounds in coffee oil and can be used for quantifying the impact of typical processes such as roasting or storage under different conditions. The influence of factors such as the water activity and the geographical origin of the coffee seed can be also determined.