EFFECT OF EXTRACTION CONDITIONS ON YIELD AND BIOACTIVE COMPOUNDS OF COFFEE PULP EXTRACT

Abstract

Coffee pulp is a by-product of coffee processing that contains a considerable amount of bioactive compounds. The extraction conditions have a great effect on the yield and bioactive compounds of coffee pulp extract. This study aimed to investigate the effect of extraction conditions for shaking-assisted maceration and Soxhlet extraction on the yield and bioactive compounds of coffee pulp from West Java, Indonesia. For shaking-assisted maceration, extraction time (30, 60, 90, and 120 min), shaking speed (30, 60, 90, and 120 movement/min), and concentration of citric acid (0, 3, 5, and 8 % weight per volume) were varied whereas for Soxhlet extraction, sample to solvent ratio (1:7, 1:10, 1:12, and 1:15 weight per weight), concentration of ethanol (0, 70, and 96 % volume/volume), and concentration of citric acid (0, 3, 5, and 8% weight per volume) were varied during the extraction process to determine their influence on the yield and bioactive components of the coffee pulp extract. The highest yield of coffee pulp extract (27.6% weight/weight) was obtained when the coffee pulp was extracted by Soxhlet extraction using 8% citric acid concentration in 96% ethanol with a material to solvent ratio of 1:15. Bioactive compounds in the coffee pulp extract had been determined and found to contain total phenolic compound of 20.3-21.3 mg GAE/g, anthocyanin content of 6.0-13.8 mg/L, vitamin C content of 1.5-1.7 mg/g, and flavonoid content of 3.4-3.8%. The coffee pulp extract also demonstrated an antioxidant activity with IC50 values of 277.89 - 253.57 ppm.