Effects of Naturally Occurring Phenolic Compounds in Coffee on the Formation of Maillard Aromas

Abstract

The major naturally occurring phenolic compound in coffee is chlorogenic acid, or 5-caffeoylquinic acid. During coffee roasting, chlorogenic acid undergoes different thermal reactions and has significant impacts on the sensory properties of roasted coffee. It was hypothesized that caffeic, ferulic, and chlorogenic acids as antioxidants could affect formation of nitrogen-containing and sulfur-containing heterocyclic compounds and Strecker degradation products under roasting conditions. The objective of this study was to investigate effects of naturally occurring phenolic compounds in coffee on the formation of Maillard aromas and explore the mechanisms. The results from study on the roast model systems of D-glucose with L-lysine and D-glucose with L-leucine indicated that naturally occurring phenolic compounds in coffee like caffeic, ferulic, and chlorogenic acids could inhibit alkylpyrazine formation under the coffee roast conditions. Moreover, the results suggested that the three phenolic compounds were strong inhibitors of the Strecker degradation of leucine. In addition, caffeic and chlorogenic acids greatly reduced the formation of thiazoles, thiophenes, 5,6-dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine, and 3, 5-dimethyl-1,2,4-trithiolane in the roast model systems of L-cysteine and D-glucose.