An immobilized fungal chlorogenase rapidly degrades chlorogenic acid in a coffee beverage without altering its sensory properties

Abstract

Chlorogenic acids are among other compounds suggested to cause stomach discomfort after coffee consumption. Following up a study on coffee powder treated with buffered solution of the p-coumaroyl esterase from Rhizoctonia solani, freshly brewed coffee was treated to explore, if this enzyme would likewise work well in the complex beverage containing possible inhibitors. Using 40 mU of esterase/mL regular coffee brew, an 89% decrease of the 5-O-chlorogenic acid concentration (30 min, ambient temperature) with a concurrent increase of caffeic acid concentration was observed. Aroma dilution analysis and sensory studies showed that the treatment did not alter the aroma and taste profiles significantly (p < 0.05). Immobilization experiments using spin columns filled with mesoporous silica or aldehyde-activated agarose as carrier materials showed that the latter degraded chlorogenic acid at an initial reaction rate of 98% and still > 80% after thirty hours. After this time, 500 mL of coffee beverage, equivalent to around 5000 bed volumes, had passed through the column. The high activity of the enzyme, which allowed processing at ambient temperature, and the high specificity, which together resulted in an unchanged flavor profile of the beverage, provide a promising basis for applying the enzyme immobilisate on larger scales.