A REVIEW OF ULTRASOUND-ASSISTED EXTRACTION OF BIOACTIVE COMPOUNDS FROM COFFEE WASTE

Abstract

The objective of this paper is to review the effectiveness of ultrasound-assisted extraction, particularly targeting phenolic and flavonoid compounds from coffee waste. The mechanism, advantages, disadvantages and some of the important factors affecting ultrasound-assisted extraction are discussed. Previous studies and current applications of ultrasound-assisted extraction on the extraction of phenolics and flavonoids from various coffee wastes are reviewed. Ultrasound-assisted extraction is easier to use, can be done at the room temperature, increases efficiency, utilizes less solvent and energy, reduces operating costs, and better preserves of the bioactivity of thermosensitive compounds. This review shows that key parameters affecting the extraction of bioactive compounds using ultrasound technology are temperature, contact time, type of solvent, solid to solvent ratio, ultrasonic power and ultrasonic frequency. In conclusion, all the reported applications reveal that ultrasound-assisted extraction stands out as an emerging and green extraction technique to extract phenolic and flavonoid compounds from coffee waste.