Abstract

Background: Coffee is one of the most commonly consumed drinks around the world. During the coffee roasting process, sugars and amines undergo a violent Maillard reaction, resulting in a large number of volatile and non-volatile components. These ingredients have a huge impact on the formation of coffee flavor. In addition, many Maillard products in coffee have also been proven to exert antioxidative, anti-inflammatory effects, etc.

Objective: The objective of this research is to discover non-volatile Maillard reaction products in roasted coffee beans.

Methods: A pair of enantiomers pyrrolomorpholine spiroketal alkaloids 1a and 1b were isolated from roasted beans of Yunnan coffea Arabica. Their planar structures were elucidated by extensive spectroscopic analysis, HRESIMS spectra and X-Ray diffraction.

Results: Two pyrrolomorpholine spiroketal alkaloids were isolated from roasted Arabica coffee beans. And their formation pathway via Maillard reaction was deduced.

Conclusion: Their influence on the formation of coffee bitterness and biological functions is worthy of being further studied.

Keywords: Coffee, coffea arabica, roasted beans, pyrrolomorpholine spiroketal, alkaloid, maillard reaction.