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pp.660-665
The effects of ultrasound-assisted extraction (UAE) on the physicochemical and sensory characteristics of coffee beverage were investigated. Coffee powder (4 g) was soaked into 80 mL distilled water and extracted for 15, 30, 60, 120, 180, 240, or 300 sec at 60℃ in an ultrasonic bath (40 kHz, 300 W). Hot-water extraction (HE) at 80℃ for 300 sec was used as a control. Content of soluble solids in coffee beverage prepared by UAE (60~300 sec) was same or higher than those of HE, however, no significant differences were observed among the four beverages extracted for more than 120 sec. Clarity and browning index of beverage prepared by UAE (15 sec) and by HE were significantly higher and lower, respectively, compared to those of the other. Content of phenolic compounds was lower and higher respectively, in beverage prepared by UAE (15 sec, 30 sec) and UAE (60~300 sec) than by HE. DPPH radical scavenging activity was highest in beverage prepared by UAE (15 sec) and HE. Sensory evaluation showed that color, aroma, taste, and overall acceptability were rated with the best score for beverage prepared by UAE (15 sec) and the worst score for beverage prepared UAE (120~300 sec). Therefore, ultrasound-assisted extraction can be used for improving quality of coffee beverage.
