Effects of wet processing on coffee quality

Abstract

Objective: This study aimed to optimize the wet processing of coffee. Methods: The effects of pectinase concentration, temperature and drying method on the contents of flavor precursors and flavor substances in coffee beans were investigated. The quality ranking was obtained by grey correlation analysis and the volatile substances were analyzed. Results: There were significant differences in the contents of protein, crude fat, caffeic acid, caffeine, chlorogenic acid and volatile compounds among different pectinase concentration, temperature, sun drying and heat pump drying. Grey correlation analysis showed that the quality ranking of coffee in the 2% pectinase + 27 ℃+ sun-drying treatment group was the first. The protein content in green coffee beans was 14.04%, the crude fat content was 9.05%, the caffeic acid content in roasted coffee beans was 1.05 mg/g, the caffeine content was 1.41%, and the chlorogenic acid content was 13.89 mg/g. The relative contents of the main volatile substances esters and acids were 40.87 μg/g and 7.62 μg/g, respectively. Conclusion: The comprehensive quality of coffee obtained by 2% pectinase + 27 ℃ + sun-drying was the best.

Keywords

• coffee
• wet processing
• enzymatic degumming
• drying method
• grey correlation degree